Purpose: Black women in the United States face poor outcomes across reproductive health measures—from pregnancy outcomes to gynecologic cancers. Racial health inequities are attributable to systemic racism, but few population studies of reproductive health outcomes integrate upstream measures of systemic racism, and those who do are limited to maternal and infant health outcomes. Advances in understanding and intervening on the pathway from racism to reproductive health outcomes are limited by a paucity of methodological guidance toward this end. We aim to fill this gap by identifying quantitative measures of systemic racism that are salient across reproductive health outcomes.Methods: We conducted a review of literature from 2000 to 2019 to identify studies that use quantitative measures of exposure to systemic racism in population reproductive health studies. We analyzed the catalog of literature to identify cohesive domains and measures that integrate data across domains. For each domain, we contextualize its use within population health research, describe metrics currently in use, and present opportunities for their application to reproductive health research.Results: We identified four domains of systemic racism that may affect reproductive health outcomes: (1) civil rights laws and legal racial discrimination, (2) residential segregation and housing discrimination, (3) police violence, and (4) mass incarceration. Multiple quantitative measures are available for each domain. In addition, a multidimensional measure exists and additional domains of systemic racism are salient for future development into distinct measures.Conclusion: There are quantitative measures of systemic racism available for incorporation into population studies of reproductive health that investigate hypotheses, including and beyond those related to maternal and infant health. There are also promising areas for future measure development, such as the child welfare system and intersectionality. Incorporating such measures is critical for appropriate assessment of and intervention in racial inequities in reproductive health outcomes. Emerging research in maternal and infant health incorporates some measures of structural racism.17–19 While these are significant contributions, there is a need for population reproductive health studies—beyond perinatal outcomes—to include measures of systemic racism to identify underlying mechanisms of outcomes among Black women, and to provide the evidence base for effective intervention.Yet, few public health studies incorporate measures of systemic racism.4 describe approaches to conceptualizing structural racism. Groos et al.20 operationalize selected concepts for general health research, yet call for further elucidation of these measures specific to subdisciplines. To our knowledge, efforts in reproductive health have been limited to conceptual frameworks focusing on maternal health, infant health, and HIV/sexually transmitted diseases (STDs).21 The goal of this narrative review is to fill this gap by describing quantitative measures of exposure to systemic racism that can be applied in population-based studies of reproductive health.There is limited methodological guidance toward this goal. Gee and Ford11 Accordingly, we place reproductive health within the sociopolitical context of interlocking systems of power and oppression and recognize that freedom from these systems is critical for realizing reproductive justice.We consider reproductive health to comprise all clinical, quality of life, and health service outcomes related to fertility management and childbearing, menstruation and menopause, benign and malignant gynecologic conditions, and sexual functioning. Our approach to reproductive health is indebted to the Reproductive Justice movement, a grassroots movement for the rights and health of women of color, which was founded in the mid-1990s.22 Fundamental Cause Theory guides selection of measures that give rise to differential access to “flexible resources” that operate along “replaceable pathways” from racism to health.23 Public Health Critical Race Praxis is the methodological approach to our work.24 Its tenets provide the framework by which we critically review the literature.Three conceptual frameworks guide our review. The Ecosocial Theory guides us toward literature that considers disease process as the embodiment of socioecological context—including social inequity, resource deprivation, and societal-level and historical trauma.Using these frameworks, we conducted a review of literature from 2000 to 2019 to identify studies that use quantitative measures of exposure to systemic racism in population reproductive health studies. We first examined reproductive health literature and then broadened to general population health research. We excluded any study that did not include measures at the structural or systemic level. We cataloged each measure, its application, and available data sources. We then analyzed the catalog of literature to identify cohesive domains and measures that integrate data across domains. For each domain, we contextualize its use within population health research. We then describe metrics currently in use and opportunities for their application to reproductive health research. Given limited evidence on the topic, we make conceptually founded bridges between bodies of evidence. Finally, we discuss potential measures for future development.We identified four prominent domains of systemic racism that may affect reproductive health outcomes: (1) civil rights laws and legal racial discrimination, (2) residential segregation and housing discrimination, (3) police violence, and (4) mass incarceration. 25 The 1964 U.S. Civil Rights Act (CRA) and other civil rights laws have changed the context in which racism operates, including by increasing access to resources .26 Yet legal racial discrimination persists, as do the lingering effects of overturned laws. For example, any U.S.-born Black person 56 years of age and older in 2020 lived with Jim Crow laws, which mandated segregation of health care facilities, restricted access to health care, and provided federal funding of eugenics programs, which included coercive reproductive health procedures . Immigration policy is another form of legal racial discrimination that carries out systemic racism by prohibiting access to citizenship and associated rewards to groups considered non-White. Such practices have appeared in the United States since the Naturalization Act of 1790.4 For any individual Black person living in the United States of any age, legalized racial discrimination and the remnants of overturned laws persist.21Legal racial discrimination has shaped access to resources, including mobility, income, employment, wealth, family and reproductive self-determination, and education since the founding documents of the United States.27 and that Black women born in the late 1960s had a 70% decrease in adult health risk factors and improved birth outcomes compared with Black women born earlier that decade.28 Turning to geographic variation, estrogen receptor-negative breast cancer is significantly higher among Black women born in counties with active Jim Crow Laws, compared with peers born in counties without Jim Crow laws.29There is no single established measure of exposure to legal discrimination or its abolition. Time periods spanning the passage of civil rights laws and their enforcement mechanisms, or spanning the adoption or repeal of relevant immigration policies, along with meaningful geographic units, can be used to construct cohorts that serve as proxies. Research using age-period-cohort models shows improvement in life expectancy and premature mortality among Black populations born in the decade following passage of the CRA compared with the decade before28 Infant health improvements during that time may have also been driven by implementation of maternal and child health funding under 1963 and 1965 mandates for health care provision to poor and Black populations.31The impact of variation in laws' implementation or enforcement can also be assessed using temporal or geographic cohorts. Hospitals' compliance with the 1965 Medicaid Act—which enforced Title VI of the CRA by tying funding to measures of integration—may have driven decreases in infant mortality.32 and earned mistrust of the medical system, which may inhibit care-seeking behaviors, and embodiment of historical societal-level trauma. County-level associations between hysterectomy rate and race, independent of health care access, illustrate continued relevance of Jim Crow laws for gynecologic health.33 Black women—especially those in the U.S. South—remain at higher risk of premenopausal hysterectomy.34 Higher rates of hysterectomy is concerning in its own right, and may also limit community knowledge necessary to self-assess symptoms of gynecologic cancer, such as bleeding after menopause.35 The imprint of legalized discrimination as chronic stress may increase the burden of fibroids and endometriosis.36 Intergenerational effects may occur through cultural and institutional ideologies and practices, epigenetic37 and biological embodiment of trauma and stress,38 and durable maladaptive community beliefs and attitudes.39 Given these conceptual links, measures of legal racial discrimination—using age-period-birth cohorts and geography relative to the passage and enforcement of civil rights laws—can be incorporated into population reproductive health studies.Measures of legal racial discrimination can be incorporated into a wide range of reproductive health research. Compulsory sterilization programs, for example, are salient to current reproductive health outcomes, including quality of contraceptive care delivery, mismatch between community preferences and current contraceptive offerings,40–43 Mechanisms of segregation's impact on health include isolation, resource deprivation, and concentrating exposures to poverty, community violence, and environmental toxins.43 In addition, social network disruption can reduce the economic and social stability required to access health care and other health-promoting resources.8 Social networks may be disrupted due to constrained choice in housing due to displacement related to rising housing costs, housing discrimination, and the eradication of place-based subsidized housing toward “urban renewal” projects.44Racial residential segregation is the geographic separation of groups based on race. Segregation is a well-established determinant of adverse outcomes among Black populations in the United States.45 increased odds of hypertension,46 diabetes, obesity,47 premature mortality,48 and racial disparities cancer.41 Experiences of residential segregation early in life can have adverse consequences across the life course.49 Some studies illustrate a potential protective effect of living in racially homogenous areas, perhaps due to increased social cohesion where there is racial concordance between neighbors.50Living in geographic areas characterized by racial and economic polarization is associated with higher rates of less treatable breast cancer subtypes,50 Race-based housing discrimination was outlawed with the Fair Housing Act in 1968,50–52 but housing discrimination and its health effects persist.43 Living in a neighborhood characterized by high racial bias in mortgage lending has been associated with increased all-cause mortality among Black women diagnosed with breast cancer53 and colorectal cancer.53 Residing in neighborhoods with a history of redlining increases vulnerability to declines in self-rated health.51Housing discrimination—including mortgage loan discrimination and redlining—has been used as measures of structural precedents of segregation.49 and these stressors persist across generations.37Experiences of residential segregation early in life have adverse health consequences across the life course, even after relocation,50 The mortgage lending bias index represents the adjusted odds of home mortgage application denial for a Black compared to a White applicant within a geographic area. The redlining index represents the odds of denial of a mortgage application in particular areas compared with other areas.50 Both measures use data from the Home Mortgage Disclosure Act database.Racial bias in mortgage lending and redlining is captured with indices using spatially continuous estimates.54 Although not explicitly a measure of racism-related variables, the ADI comprises indicators of conditions that can be conceptualized as downstream effects of systemic racism. Datasets at the state- and census-block levels using American Community Survey data for two timeframes in the 2000s are publicly available.55 The ICE quantifies the spatial feature of inequitable group relationships within an area and can be constructed using census data to describe racial or economic spatial inequity, or both in combination.56 The combined race and economic ICE outperforms measures using only race, income, or simple poverty rates in estimating the risk of health outcomes such as maternal health,56 and toxic environmental exposure.57 ICE is adaptable to different scales,56 which is useful for disentangling effects across geographic units.4Two summary metrics of the conditions created by segregation are prominent in the literature: The Area Deprivation Index (ADI) and the Index of Concentration at the Extremes (ICE). The ADI, which comprises 17 household-level socioeconomic indicators, describes the socioeconomic disadvantage of an area with high reliability and validity across census tracts.59; this pathway has been included in only a single study of gynecologic cancers and in no studies of benign gynecologic conditions of which we are aware. Promisingly, an association was found between higher scores on the ADI and cervical cancer incidence, late-stage diagnosis, and mortality rates, with a greater association for Black than White women.61 Using ADI and ICE in studies of gynecologic cancers62 and conditions such as fibroids63 would be a novel contribution to the literature. Including both measures would help to differentiate the roles of resource deprivation and inequity. Further upstream, mortgage loan bias and redlining could be used to examine the role of systematic disinvestment and segregation in these same outcomes within the life course and across generations.Multiple opportunities exist to investigate the role of residential segregation and housing discrimination in reproductive health outcomes. For example, while it is well documented that Black women residing in areas with higher disadvantage in the context of racialized and economic-based spatial inequity experience greater odds of infant mortality and preterm birthFinally, qualitative research could supplement these quantitative measures to better understand the rich and complex role of social network formation and disruption in stress, gynecologic care delay, other mechanisms of harm, and coping responses.65 Today's institution of policing originated with slave patrols in the South, efforts to control immigrant populations in the North, and brutalization of Indigenous people across the continent. Its entrenchment has been bolstered by laws and policies that encourage overpolicing of Black neighborhood, reflect xenophobic and White supremacist ideologies, and criminalize behaviors more effectively addressed through public health intervention.64 Policing is enacted by policies and actions of police departments, federal law enforcement, and immigration enforcement (including immigration policies and enforcement practices). Physical and psychological violence occur through use of force, psychological intimidation, and community-level surveillance.65–68 Pathways to adverse health outcomes include direct injury and psychological harm, acute and chronic trauma and stress, and behavior change to limit exposure to policing, which inhibit access to health-promoting resources.65–68 Exposure to police violence also causes economic hardship due to costs of injury and judicial processes, or elimination of a household or community adult.65 Black people are at higher risk of death and nonfatal injury compared with White people.65 The adverse effects of police violence on Black people extend beyond direct encounters. In states with higher rates of police-involved deaths of unarmed Black people, Black people experience more days of mental health distress.69 Prevalence of asthma, diabetes, and high blood pressure is higher in neighborhoods where pedestrian stops are more likely to escalate into frisking, and where the frequency of such stops is higher among people of color.70Police violence is a mechanism of structural racism that is of pressing public health concern.72 Databases that combine reports from official sources, crowd-sourcing, news, and public records request account for the largest possible proportion of actual cases.72 For example, the Fatal Encounters database has been used to estimate county-level racial inequity in risk of homicide by police among males.73 State-level mental health effects have been investigated using the Mapping Police Violence database, linked to Behavioral Risk Factor Surveillance System data.69 Studies of health effects of immigration enforcement often use population surveys or administrative data from a timeframe before and after an immigration raid or policy change.75Efforts to incorporate measures of police violence into population health studies are made more difficult by limitations of official administrative databases: the Centers for Disease Control and Prevention's National Violent Death Reporting System, the U.S. National Vital Statistics System, and the Federal Bureau of Investigation's Uniform Crime Reporting System.76 Finally, the Jackson, Hogue, Philips contextualized stress measure assesses contextual and intersectional racial and gendered stress and includes two indicators of exposure to police violence.77 Using this measure, a positive association was found between antenatal depressive symptoms and anticipated negative youth encounters with police.78The Survey of Police-Public Encounters captures self-reported police violence using a 27-item scale and has been conducted among a representative sample in four urban areas in the United States.79 and for Latina, Middle Eastern/North African, and Arab women following changes in the social and political environment toward anti-immigrant sentiments.81 Anxiety related to constrained resources following an immigration raid has contributed to decisions to delay childbearing—demonstrating another stress pathway.82Given the strength of association between stress and adverse reproductive health outcomes, and the documented association between psychological distress and police violence, it may be that police violence has far-reaching effects in reproductive health through early life, chronic, and intergenerational stress. This pathway is evident in studies finding adverse birth outcomes among Latinx parents following immigration raids or apprehensions,78 could be incorporated into population surveys investigating the role of stress not only in birth outcome but also in fibroids or histologic subtypes of gynecologic cancer, for example. Data from sources on policing exposure described above could be linked to nationally representative surveys that include mental health outcomes.To broaden this evidence to other forms of policing and across reproductive health domains, the Jackson, Hogue, Philips contextualized stress measureLimited mobility due to overpolicing of Black neighborhoods could also impact the ability to seek care for gynecologic health issues—abnormal uterine bleeding, pelvic pain from fibroids or endometriosis, and infertility. These conditions are associated with markedly worse burden and/or worse outcomes among Black women, but are not directly life threatening, so are particularly susceptible to care delays.84 Punitive policies and overpolicing of Black neighborhoods have resulted in the disproportionate impact of incarceration on Black people.83 Black children are five times more likely than White children to experience maternal incarceration.85 In 2006, nearly half of Black women had an immediate or extended family member imprisoned.86 Adverse health outcomes occur during incarceration and after release through policies and discrimination that inhibit access to housing, employment, and health care.84Mass incarceration in jails, prisons, and immigration detention centers is recognized as a steadily worsening mechanism of structural racism.84 Women whose partners are incarcerated are at greater risk for stroke, heart attack, and poor self-rated overall health.87 Higher rates of incarceration are associated with higher community-level prevalence of asthma and psychiatric morbidity.84 Community effects may occur because of financial strain; legal financial obligations place an immense burden on families and communities, and are often shouldered by women.88 Other mechanisms include reduced social support due to the removal of community members, incarceration-related stigma, or forced displacement; political disenfranchisement; and higher levels of both acute and chronic stress.Adverse health effects also occur among populations that are proximate to incarceration by relationship or geography. Parental incarceration is associated with asthma, behavioral issues, anxiety, depression, and worse overall self-rated health.84 State--level rates of incarceration can be estimated using Public Use Microdata Samples data, which are collected at the decennial census and contain flags for sample members who are institutionalized.90 A more nuanced estimation of all current and formerly incarcerated individuals to assess community-level effects can be constructed90 using a combination of data sources from the U.S. Department of Justice and U.S. Bureau of Prisons.90Linking administrative incarceration data with population-level health metrics provides the most accurate method by which to estimate health effects and inequities.91 risk of contracting infections disease,92 and racial disparities within these outcomes.84 Parental incarceration is associated with increased risk of infant mortality and increases in inflammatory markers among female children85—well documented as part of the pathway connecting pre-conception stress with adverse pregnancy outcomes.93 Coercive contraceptive practices and family separation are also more likely to occur in the context of mass incarceration.91Studies that have leveraged state-level data to study the effects of incarceration on reproductive health have documented higher incidence of infant mortality, poorer access to or quality of prenatal care,63 In addition, access to care for any of these conditions may be hindered by fear of incarceration due to punitive approaches to behaviors such as drug use, or to conditions such as homelessness or immigration status, all of which are better addressed through an approach that prioritizes addressing structural causes of these conditions.These measures might be meaningfully extended to studies of reproductive health outcomes beyond maternal and infant outcomes. Pathways for future investigation include the role of mass incarceration in (1) care delay, due to limited social support or economic strain, which may contribute to later-stage diagnosis of gynecologic cancers; or (2) physiologic stress mechanisms that promote more aggressive gynecologic disease.94 identify four domains for measuring state-level variation in exposure to structural racism: the Black–White relative proportions of political participation, employment and job status, educational attainment, and judicial treatment.94 Data for the index are drawn from the U.S. Census Bureau; National Conference of State Legislatures; Bureau of Labor Statistics; and the Sentencing Project.94 Using this index, higher levels of structural racism have been associated with higher odds of small-for-gestational-age birth95 and higher rates of infant mortality96 among Black residents. This measure could be feasibly applied across the spectrum of reproductive health outcomes.Employing multidimensional measures of structural racism may be useful to understand the interlocking and compounding harms of its various mechanisms, which may otherwise be obfuscated when using only discrete measures. Lukachko et al.21 For example, Black people are disproportionately exposed to the child welfare system compared with other racial and ethnic groups.98 Exposure to foster care can adversely affect adult health outcomes in a cumulative manner, contributing to higher rates of hypertension, asthma, diabetes, cardiovascular risk, chronic health conditions, stroke, and epilepsy,100 as well as STDs.101 Although no national data are available, there are several large-scale studies that capture foster care involvement and could be linked with reproductive health data. The California Health Interview Survey is the largest statewide health survey administered in the United States. Several regional studies also exist, including the Midwest Evaluation of the Adult Functioning of Former Foster Youth.101There are other mechanisms of structural racism that impact health, for which there are not yet quantitative measures.22The literature we reviewed largely excludes trans and nonbinary individuals whose reproductive and gynecologic health may be uniquely affected by the exposures described above. Developing measures of structural racism that uniquely effect populations with marginalized gender and sexual identities will help better assess the underlying, interlocking mechanisms of harm, and candidate intervention foci.102 Having a cognitive or physical disability, for example, which is disproportionately more likely among Black people,103 increases risk of exposure to violent policing and exacerbates health consequences of direct or community-level exposure.104 The stress pathways described for each factor above are likely made worse in the case of existing disability. Immigration status is another dimension that warrants attention. The policies, practices, and ideologies of a racialized system of immigration enforcement that targets Black people and people of color act as forms of legalized racial discrimination, as mechanisms of policing and incarceration, and drive residential segregation.66–68 Others note the need to understand the intersection of race, nativity, and immigration status in health research,106 and emerging research describes the salience of this intersection for maternal and infant health outcomes.107–109Indeed, intersectionality—a concept coined by Kimberlé Crenshaw—is core to the implementation of a reproductive justice framework, and therefore, intersecting identities are a necessary focus of population reproductive health research.Measures of exposure to systemic racism are important to include in population-based studies of reproductive health. The existing evidence suggests there are many plausible hypotheses to be investigated beyond those related to maternal and infant health. We reviewed some of the many domains of systemic racism that engender and exacerbate adverse reproductive health outcomes among Black women in the United States, described existing measures of these domains, and presented opportunities for applying them in population reproductive health studies. Importantly, we focused on systemic racism. When we limit our understanding of the effects of racism to interpersonal and psychosocial pathways, we reinforce the notion that race and racism occur at the individual level and we obfuscate and absolve the sociopolitical structure of racism. The carefully constructed scaffolding of interlocking systems and ideologies that reinforce the racialized distribution of resources is intentionally hidden from view, not least by limiting the means to measure it. Systemic racism requires our explicit, empirical attention to identify effective means to deconstruct it and its contributions to racial inequities in reproductive health. Efforts to advance equity in reproductive health require population health research that explicitly incorporates measures of systemic racism.23 Examining and intervening on a single domain or considering domains as static will not reduce racial inequities in reproductive health.23 It is recommended that researchers not only include multiple measures in historical context but also constantly reassess how measures must be altered to capture the iterative transformation of mechanisms of harm.As a fundamental cause of health inequities, systemic racism constantly replaces the mechanisms that ensure unequal distribution of power, prestige, social connections, money, and freedom.110 and to integrate epigenetic mechanisms.112 Finally, while our focus is systemic racism in the United States, our domain and framework could be adapted for other contexts.Our review corroborates previous recommendations to take a life course perspective that examines mechanisms including social network formation, early childhood stress, and compounding stress,Efforts to improve reproductive health outcomes among Black women require population health research that explicitly incorporates measures of systemic racism. Our review illustrates conceptual and methodological paths toward that end.


Research on nanoparticle enhanced fluids has increased rapidly over the last decade. Regardless of several unreliable reports, these new fluids have established performance in heat transfer. Lately, polyethylene glycol with nanoparticles has been demarcated as an innovative class of phase change materials with conceivable uses in the area of convective heat transfer. The amplified thermal conductivity of these nanoparticle enhanced phase change materials (PCMs) over the basic fluids  is considered one of the driving factors for their improved performance in heat transfer. Most of the research, however, is centered on the thermal conductivity discussion and less on viscosity variation, while specific heat capacity seems to be fully ignored. This short review abridges most of the recent investigations on new PEG-based fluids and is dedicated especially to thermophysical properties of the chemicals, while a number of PEG-based nanofluids are compared in terms of base fluid and/or nanoparticle type and concentration. This review outlines the possibility of developing promising new heat transfer fluids. To conclude, this research is in its pioneering phase, and a large amount of experimental and numerical work is required in the coming years. Phase change materials (PCMs) have formed one of the most popular topics in research for the last 25 years. Despite the large body of existing research on phase change material properties and applications and the several published review papers, it is worth outlining the polyethylene glycol (PEG) family as one of the challenging classes of phase change materials with direct application in heat transfer enhancement.One of the first comprehensive reviews on thermal storage systems and PCMs was accomplished by Zalba et al.  in 2003.-Thermal properties: good phase transition temperature, good heat transfer capabilities , and a high latent heat;-Physical properties: good phase equilibrium, high values for density, and small vapor pressure;-Kinetic properties: no conditions for supercooling and a good crystallization rate;-Chemical properties: a very good chemical stability over time, lack of toxicity and absence of fire hazard , a very good compatibility with other materials from the same system , lack of or low degradation after a number of freezing or melting processes;-Preferable economic indicators, such as abundancy, large scale availability, and low costs.Sharma et al.  also conThe classification of PCMs is illustrated in The advantages and drawbacks of classes of PCMs are depicted in This paper focuses on the polyethylene glycol (PEG) phase change material, though it is not our intention to deliver another review on PCMs, since many similar papers are already published in the open literature see ,4,5,6,7),5,6,74,52–CH2)n–OH, and its application areas are outlined as follows:-Chemical applications ;-Medicine ;-Biology -Commercial uses -Industrial applications ;-Recreational applications.Polyethylene glycol (PEG), alongside paraffin and fatty acid, is an organic PCM, and it has a congruent phase change with a good nucleation rate . Consequently, the global drag effect present in the medium is amplified, leading to an escalation in energy dissipation generating the augmentation in the nanofluid viscosity .Results for specific heat capacity are rather limited in the open literature and are briefly discussed, since no valid conclusion can be formed. Results of Marcos et al. ,18 show Marcos et al.  performeMarcos et al.  measuredThis short review discusses polyethylene glycol, dispersions of nanoparticles in several polyethylene glycol fluids, and their possible use in thermal energy storage as nanoparticle enhanced phase change materials (NePCMs). According to studies identified in the open literature  and other forms of PEG with different characteristics ought to be studied in future experiments for a complete analysis of the influence of both nanoparticle type and polymer chain dimension on PEG-based NePCMs.


Strategies to create functional organs and tissues is of great interest for use in regenerative medicine in order to repair or replace the lost tissues due to injury, disease, as well as aging. Several new treatment options, including stem cell treatments and tissue-engineered substitutes for certain indications, have been approved by Food and Drug Administration (FDA) and are currently available. This special issue will cover new therapies and strategies that are currently being investigated under preclinical and clinical settings. Organs and tissues in mammalian systems are endowed with a limited regenerative capacity compared to non-mammalian vertebrates and invertebrates . AdditioBiomolecules is dedicated to highlighting the current contributions of research on therapeutic targets and bioengineering strategies to promote organ repair and regeneration. Strategies for developing functional organs and tissues from cell culture models, tissue-engineered substitutes, biomolecules from cells, molecular and cell biological approaches, surgical applications, and stem cell therapies are the major contributions to this special issue. A large number of studies have developed translational approaches to replace damaged cells, tissues, and organs [This special issue of d organs ,14,15,16d organs ,17,18. Ad organs . The recd organs . The conThe contributions by Urkasemsin et al. ‘Strategies for Developing Functional Secretory Epithelia from Porcine Salivary Gland Explant Outgrowth Culture Models’ propose a method to develop transplantable human salivary gland secretory epithelia for patients with salivary gland hypofunction and xerostomia . SimilarSabbah et al. describe the need for a potency assay in order to assess the transplantability of endothelial progenitor cells for therapeutic applications. Endothelial cell damage is an underlying factor in a number of vascular disorders, with the concept of endothelial progenitor cell (EPC) therapy offering attractive treatment to these disorders ,20. The Using small and large animal spinal cord injury (SCI) models, Mukhamedshina et al. , in theiThe study by Triaca et al. investigates the therapeutic potential of small stable nerve growth factor (NGF) peptides as tropomyosin receptor kinase A (TrkA) agonists for treating pathologies of the central and peripheral nervous system . NGF is The production of NGF by recombinant methods has made it possible to test its clinical efficacy, but basic principal limitations have remained unsolved. A critical limitation is the inability of NGF to cross the blood–brain barrier (BBB) upon systemic administration of the protein ,26. ConsA major complication following the implantation of a biomaterial or prosthesis is the incidence of infections caused by growth of bacterial biofilms on prosthetic surfaces. In addition, despite the use of antibiotics to modify prostheses, implant-associated infections still remain challenging due to the development of bacterial resistance. To address this issue, Szałapata et al. examined the prospect of serine protease inhibitors (PIs), immobilized on prosthetic surfaces widely used in regenerative medicine, to prevent bacterial growth . InitialIn summary, these articles on the emerging therapies in regenerative medicine encompass the use of stem cell-based strategies, approaches to produce functional organs and tissues, tissue-engineered substitutes, biomolecules, recombinant peptides, and other molecular and cell-based approaches to promote organ and tissue repair. Great advances have been made in the development of new methods and technologies that implicate an exciting future for cell and tissue therapies in regenerative medicine and biomaterial-based tissue engineering. These new advances will pave the way for a better understanding of mechanisms of organ and tissue loss during injury and diseases and for the design of strategies to rebuild damaged tissues for therapeutic purposes.


Recent population-based studies have shown declines in dementia prevalence in high-income countries, suggesting that improved population cardiovascular health and rising levels of education in the past 25 year were associated with reduction of dementia risks. However, in the US, there are variations in educational attainment, prevalence and management of chronic diseases, and behaviors associated with poor cardiovascular health among racial and ethnic groups. We performed a retrospective analysis of 3,495 older individuals (65+) in 2016 who participated in Harmonized Cognitive Assessment Protocol (HCAP) subsample of the Health and Retirement Study (HRS), to examine racial/ethnic differences in risk and protective factors associated with dementia and cognitive impairment. Linking HCAP to HRS, we traced individuals back to 2000 and created a longitudinal data of HCAP population (2000-2016). We found that racial/ethnic differences in risk and in protective factors throughout the life-course were associated with racial and ethnic disparities in dementia prevalence.


The paper presents a dataset of the e-registration of rice value chain actors in Benin and Côte d'Ivoire for assessing the adoption of innovations and the diffusion of new rice technologies. Data were collected from actors after a census conducted in three steps. In the first step, main rice production regions and rice value chain actors were identified. In the second step, we updated the list of actors based on membership of actors’ associations. In third step, we did the census of all individual actors and geo-localized all farmers’ fields and villages using GPS device. Data were collected for the 2018 growing seasons. The dataset contains 17,639 observations  with 159 variables divided into six sections: (i) preliminary information on the respondents; (ii) socio-economic characteristics; (iii) information on the rice plots; (iv) knowledge, use and access to rice varieties; (v) knowledge, use and access to agricultural equipment and methods; and (vi) information on post-harvest activities. Six categories of actors were identified: foundation seed producers (420), certified seed producers , paddy rice producers , parboilers , millers (188) and traders . The dataset is available online at Mendeley data repository. The dataset is valuable for the diffusion at large scale of improved technologies and an effective monitoring of the dissemination. Data can be used by scientists to have better understanding of the rice value chains, rice production systems, the level of knowledge, accessibility and adoption of improved rice varieties and agricultural technologies, for further research regarding rice value chain development, technologies testing and socioeconomics study of rice value chain actors. Because of the large number of observations , data can be used as sampling frame for further experiment or surveys based on random samples. Moreover, the dataset has the potential of generating descriptive statistics at the most disaggregated level of administrative units or villages for different equipment, methods and varieties adopted by gender and country. Specifications tableValue of the data•The data in this article is useful because it is a large multidisciplinary dataset comprising 17,639 observations of six different categories of actors  for better understanding of the rice value chains, rice production systems and adoption of improved rice varieties and agricultural technologies.•This dataset can be used by scientists, policy makers, extensions officers, NGO and development agencies such as United Nations' organizations.•The data is valuable for further research regarding rice value chain development, socioeconomics study of rice value chain actors, yield analysis , knowledge, accessibility and adoption of rice improved varieties and technologies •The data is valuable for diffusion at large scale of improved technologies and an effective monitoring of the dissemination.•Because of the large number of observations , dataset is valuable as sampling frame for future experiment or surveys based on random samples.1The diffusion of agricultural technologies faces enormous challenges such as the identification and the geolocation of the real actors in need The questionnaire which is provided on the Mendeley data repository (see the link in the specification table and in Appendix) was used to collect information on rice actors’ demographic characteristics and specific sections related to each category of actors. For producers , 150 variables were grouped in five sections: preliminary information on the respondents; socio-economic characteristics; information on the rice plots; knowledge, use, and access to rice varieties; and knowledge, use and access to agricultural equipment and methods. Parboilers, millers and traders were interviewed, in addition to preliminary information on the respondents and socio-economic characteristics (sections 1 and 2), on nine questions related to post-harvest activities (section 6 of the questionnaire). The data resulted from surveys of six main categories of rice value chain actors: foundation seed producers, certified seed producers, paddy rice producers, parboilers, millers and traders. A total of 17,639 rice value chain actors were interviewed and geo-localized. Data were collected for the 2018 growing seasons (first and second seasons). As an example of the potential use of the dataset, 2Data were collected from rice value chain actors after a census conducted in three steps. In the first step, rice value chain actors and the regions of rice production were identified in each country. The regions selected are the major rice growing areas named hubs. These hubs are zones of high potential impact where rice research innovations are integrated across the value chains to achieve development outcomes and impact Appendix. Supplementary datahttps://data.mendeley.com/datasets/53bg88r72f/draft?a=d1748bfe-10e0-4c0e-9b5d-8649d906881dSupplementary data and files to this article can be found online at The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.


A critical barrier to improving the quality of end-of-life (EOL) cancer care is our lack of understanding of the mechanisms underlying variation in EOL treatment intensity. This study aims to fill this gap by identifying 1) organizational and provider practice norms at major US cancer centers, and 2) how these norms influence provider decision making heuristics and patient expectations for EOL care, particularly for minority patients with advanced cancer.This is a multi-center, qualitative case study at six National Comprehensive Cancer Network (NCCN) and National Cancer Institute (NCI) Comprehensive Cancer Centers. We will theoretically sample centers based upon National Quality Forum (NQF) endorsed EOL quality metrics and demographics to ensure heterogeneity in EOL intensity and region. A multidisciplinary team of clinician and non-clinician researchers will conduct direct observations, semi-structured interviews, and artifact collection. Participants will include: 1) cancer center and clinical service line administrators; 2) providers from medical, surgical, and radiation oncology; palliative or supportive care; intensive care; hospital medicine; and emergency medicine who see patients with cancer and have high clinical practice volume or high local influence (provider interviews and observations); and 3) adult patients with metastatic solid tumors and whom the provider would not be surprised if they died in the next 12 months and their caregivers (patient and caregiver interviews). Leadership interviews will probe about EOL institutional norms and organization. We will observe inpatient and outpatient care for two weeks. Provider interviews will use vignettes to probe explicit and implicit motivations for treatment choices. Semi-structured interviews with patients near EOL, or their family members and caregivers will explore past, current, and future decisions related to their cancer care. We will import transcribed field notes and interviews into Dedoose software for qualitative data management and analysis, and we will develop and apply a deductive and inductive codebook to the data.This study aims to improve our understanding of organizational and provider practice norms pertinent to EOL care in U.S. cancer centers. This research will ultimately be used to inform a provider-oriented intervention to improve EOL care for racial and ethnic minority patients with advanced cancer.Clinicaltrials.gov;  NCT03780816; December 19, 2018. The National Academy of Medicine has identified increasingly aggressive, burdensome and expensive end-of-life (EOL) treatment as a major public health problem . The AmeDespite attention focused upon integrating early palliative care into advanced cancer treatment, –15 ICU aWe posit that a critical barrier to improving the quality of EOL cancer care in the US – and among minorities in particular – is our lack of understanding regarding the mechanisms underlying cancer center variation in EOL treatment intensity . The oveOur study aims to study mechanisms underlying cancer center variation in EOL treatment intensity among minority and non-minority patients using a qualitative, case study design and has two objectives. First, we will identify the local organizational and provider practice norms that influence decisions about later-line chemotherapy, hospice, and ICU use among minorities with advanced cancer at major US cancer centers. Second, we will assess the influence of these norms on patient and family expectations and provider decision making heuristics for later-line chemotherapy, hospice, and ICU use among minorities with advanced cancer at major US cancer centers. Below we describe our qualitative study design approach to meet our study objectives.We chose a qualitative case study design at six sites to identify local organizational and provider practice norms that influence variation in EOL treatment intensity, particularly for minority patients. Based on 2016 Medicare claims data analyses,  we will > 15%. We measured EOL care intensity based upon risk-adjusted metrics of EOL quality using 2016 Medicare fee-for-service claims data: receipt of chemotherapy in the last 14 days of life (NQF #0210), intensive care unit (ICU) admission in the last 30 days of life (NQF #0213), and non (NQF #0215) or late (NQF #0216) hospice referral. Our approach to calculating these EOL quality metrics has been published elsewhere [We will target National Comprehensive Cancer Network (NCCN) and National Cancer Institute (NCI) Comprehensive Cancer Centers for our study because they set national standards for high quality cancer care. We will engage up to six sites serving a high proportion of African American patients, ranging in EOL care intensity, and theoretically sampled, to maximize our ability to compare and contrast organizational and provider practice norms related to EOL care. We defined high proportion of minority patients as lsewhere . Given tlsewhere . Followilsewhere , 36 we wWe will employ qualitative case study research methods in this study, including inpatient observation procedures and provider, patient, and leadership semi-structured interviews, that have been previously developed and piloted , 37–39. The study team will collect 3 types of data: field notes from direct observation of inpatient and outpatient cancer care and cancer tumor boards; transcribed audio-recorded semi-structured interviews with cancer center leadership, providers, and patients, family members, and caregivers; and artifacts Table . We willSemi-structured interview guides for site leadership focus on institutional norms, including resources, programs, and policies related to EOL care and outcomes, as well as site-specific workflows and scheduling logistics in preparation for site visits. Cognitive mental models semi-structured interview guides for providers, which include EOL case vignettes, explore motivations, decision heuristics, and/or rationalizations . Six EOLSite visit teams will consist of 2–3 researchers. We will identify a site-specific principal investigator (PI) at each site to help facilitate support from site leadership, and identify and recruit informants for pre site-visit interviews, and providers for site-visit observation and interviews. Up to two months in advance of the site visit, the study team will conduct leadership interviews by phone, including physician and nursing leaders, outpatient oncology practice managers, and key referral service line leaders from palliative/supportive care, hospital medicine, and intensive care. We will approach other site leaders for interviews at the suggestion of the site PI. When necessary, leadership interviews will take place during and after site visits.One month in advance of the site visit, the study team will recruit providers for observation in the inpatient and outpatient setting. The observation schedule will involve one researcher assigned to each observed provider for a half-day observation in outpatient clinics (morning or afternoon session), the emergency department (by shift), and inpatient setting (by timing of daily service or consult rounds), as well as scheduled tumor boards and family meetings. Selection criteria for providers to observe and interview focus on maximizing our ability to assess provider norms for advanced cancer care within the particular institutional context that we will explore during leadership interviews. Provider selection criteria includes providers who manage patients with: 1) metastatic solid tumors  and have either 2) high volumes of patients and/or 3) high peer influence, as perceived by the site PI or other key informants. We seek to recruit medical, radiation, and surgical oncology providers as well as palliative/supportive care providers who see cancer patients  adults aged 21 years or older; with 2) metastatic solid tumor; 3) whom the provider would not be surprised if they died in the next 12 months; and 4) seen by a consented provider. We will seek to recruit equal numbers of minority and non-minority patients. We will digitally record all interviews and compensate each participant for participating.We will use a qualitative and mixed methods data analysis platform, Dedoose, to manage and analyze all transcribed field notes, interviews, and artifacts, and link relevant data to contextual information  . We will develop a codebook first deductively, using our theoretical model, findings in the literature, and prior research and then inductively, through an iterative process of close readings and discussion of the data in order to identify additional codes. Three qualitative researchers will apply the codebook to the data, two who will divide and code all the data, and one who will assess reliability of coding by reviewing a subset of the coded data. All three qualitative researchers will discuss differences in coding and resolve by consensus. We will repeat the analysis process after each site visit, to conduct constant comparative analysis regarding similarities and differences between and within sites in support of study aims 1 and 2. After completion of each site visit, the study team will develop a written summary of preliminary quantitative and qualitative findings specific to the site, which will then be sent to all participants from that site, to assess initial validity of the site-specific findings. After completion of all site visits and analysis of data, we will send final study reports to participating sites.N = 12) is comprised of 25% racial and ethnic minority researchers. As such, we seek to incorporate greater diversity of racial and ethnic knowledge, as well as disciplinary perspective, through an external advisory board with deep topical expertise in cancer care, palliative care, racial and ethnic health equity, and social norms. Additionally, to address potential researcher bias, the entire study team completed implicit bias training focused on unconscious biases related to attitudes about race, ethnicity, cancer, cancer treatment, death, and dying. One researcher participating in data collection will remain blinded to sites’ EOL treatment intensity classification until data collection is complete.Our research team is also conscious of conducting purposefully informed and respectful research on the cancer experiences of racial and ethnic minorities, and we have taken steps to ensure scientific rigor of our approach and results through study design development and will continue to do so through data collection and data analysis. Based in a relatively non-racially diverse geographic region, our team  and is considered minimal risk. All participating sites will 1) waive independent IRB approval in favor of acknowledging Dartmouth’s IRB, 2) rely on Dartmouth’s IRB via a SMART IRB reliance, or 3) conduct a local ethical review and approval. We will obtain a waiver of informed consent for participant observation; all providers will provide written electronic consent for observation and interview, and all interviewed leadership, patients, and families will provide oral consent for interview. We have obtained a certificate of confidentiality from the National Institutes of Health (NIH) for this study.We will not record any identifiable or personal information about providers, patients, family members, caregivers, or staff in field notes, except demographic information. A unique ID number will link data from observations and interviews, including demographic data, to consented participants. The key linking the ID number and identifying information of the consented participants will be maintained on a password-protected server. Only the research team will have access to the linkage file. All data collected on individuals will be linked to their ID number alone. We will audio-record and transcribe all handwritten field notes without any identifiable information. We will store all original field notes in a locked filing cabinet, and all transcripts on a password-protected server, to which only the research team will have access. We will give a discreet lapel pin to all providers, staff, patients, family members, and caregivers who do not wish to be observed, as advertised by the informational flyers posted prior to the study team’s arrival at the site. We will not document any individual wearing such a pin in field notes, nor will we approach them for an interview.We will give all individuals participating in interviews an information sheet prior to the interview, and we will obtain informed consent verbally at the time of the interview. We will obtain informed consent verbally as many of the interviews will be conducted by phone, either before or after the site visit. The process of obtaining verbal consent has been approved by the Dartmouth College Committee for the Protection of Human Subjects. We will record all interviews, and later professionally transcribe them without any identifiable information. We will store all recordings and transcripts on a password-protected server, to which only the research team will have access. Additionally, we consulted the guidelines for end-of-life research put forth in the “Methods of Researching End of Life Care” (MOREcare) project while designing the protocol for this study . SpecifiOur study is the first comprehensive, qualitative study of local organizational and provider norms at minority-serving NCCN and NCI-designated comprehensive US cancer centers. If the aims of this study are achieved, we expect to identify targets for institutional change at cancer centers with lower EOL quality metric performance. The two main deliverables of this research will be 1) knowledge regarding norms and their impact on EOL decision making at participating cancer centers, and 2) identification of potential members of a community research advisory board to oversee future institution-level interventions aimed at improving EOL care. Respective to the first deliverable, participating cancer centers will receive a customized report of our findings about their own center following completion of our site visit. After completion of all site visits, we will work with the American Cancer Society and participating cancer centers to identify local chapters of the American Cancer Society (ACS) and provider medical societies  at which we can discuss our findings and their implications for local patients and providers.Respective to the second deliverable, we anticipate the opportunity to develop institution-level interventions aimed at EOL care in the future. Norms are fruitful for study because, once understood, they are potentially malleable through explicit leadership efforts and implementation of new forms of positive and negative sanctions. Specifically, social marketing – the use of marketing principles to influence human behavior to improve health or benefit society  – is a p


Streptococcus (iGAS) disease indicates that its incidence in the US general population is low, but limited studies show rates for American Indians and Alaska Natives (AI/AN) are severalfold higher. Major disparities in rates of iGAS exist between Indigenous and non-Indigenous populations of Australia, New Zealand, and Canada, but much less is understood about iGAS among AI/AN in the United States. Although complex host–pathogen interactions influence the rates of iGAS, including strain variation and virulence, the number and type of concurrent conditions, and socioeconomic status, the relative contribution of each remains unclear. We highlight the poor correlation between the substantial effect of iGAS among Indigenous persons in industrialized countries and the current understanding of factors that influence iGAS disease in these populations. Prospective, large-scale, population-based studies of iGAS are needed that include AI/AN as a necessary first step to understanding the effects of iGAS.Active surveillance of invasive group A  Streptococcus pyogenes (group A Streptococcus [GAS]) causes a range of pyogenic, toxigenic, and immunologic diseases with varying degrees of severity, from pharyngitis and impetigo to necrotizing fasciitis and streptococcal toxic shock syndrome  to add iGAS to the Active Bacterial Core surveillance (ABCs) program. The first survey, which assessed iGAS in the United States during 1995–1999, found an annual incidence of 2.2–4.8 iGAS cases/100,000 population , but this observation was not explored further . However, the extent and reasons for that disparity remain poorly understood.The relationship between GAS and Indigenous populations most likely involves complex interactions between pathogens and humans. Numerous studies have contributed to a long list of influencers of GAS incidence but a lack of rigorous analyses has yielded few prevention strategies  is a commonly asserted but poorly studied explanation for the high rates of iGAS among Indigenous persons. Few studies have directly measured SES when comparing iGAS rates between Indigenous and non-Indigenous populations, and the evidence is conflicting. In 1 study from Australia, half of iGAS cases occurred in the lowest socioeconomic quintile, in which Indigenous persons were overrepresented , and health outcomes varies by race  of Ontario’s 68 emm59 cases occurred in an area with a high proportion of First Nations Canadians  of 29 iGAS cases were identified as emm59, 15 (83%) of which occurred in AI  that is well described but incompletely understood .The medical and public health communities need to address the effects of iGAS among the ≈3 million AI/AN in the United States. The first step should address the lack of population-based studies of Indigenous Americans. The Indian Health Service needs to support further investigations into iGAS to fulfill its mission “[t]o raise the physical, mental, social, and spiritual health of American Indians and Alaska Natives to the highest level” (emm types to clarify the migration of strains within and among AI/AN and determination of unique host immune responses to GAS among AI/AN to guide control efforts. A tailored approach might be necessary for AI/AN or individual tribes, but better evidence would inform community-based interventions to reduce the incidence of iGAS and lay the foundation for multivalent GAS vaccines to protect communities from the most harmful GAS strains.We recommend mandatory reporting of iGAS in regions with substantial numbers of AI/AN. This reporting would encourage smaller healthcare facilities to monitor iGAS outbreaks and improve surveillance in smaller, vulnerable populations. Greater capture of isolates is integral to using population-based epidemiologic studies to better identify risk factors for iGAS specific to AI/AN. We also propose large-scale sequencing and phylogenetic studies of GAS Incidence rates of invasive group A streptococcal disease in indigenous and nonindigenous communities.


The potential of forests as a source of health has been addressed by the scientific community and is now being considered in national forest strategies, management plans and policies. Studies identifying the mechanisms by which forest characteristics may induce these effects on human health are nevertheless scarce. This systematic review of literature on forests and human health with real-life human exposure was conducted to assess the extent to which forests have been studied and described in detail and the extent to which relationships between forest variables and health effects have been reported. The analysis underlines the lack of forest descriptions in 19.35% of the 62 studies selected for review as well as the high heterogeneity of forest variables’ description. Patterns among the articles could not be identified correlating the broader forest variable (forest type) and the most studied health variables identified . These findings, together with previous ex situ researches, suggest the need to ameliorate and incorporate more accurate descriptions of forest variables within human health studies to provide data for forest management and the potential use of these habitats for preventive medicine and clinical practice guidelines. Interest in the connection between forests and human health is increasing among studies analyzing the effects of nature on human health ,2,3. TheHealth promotion is now starting to be integrated into national forest agendas leading changes in strategies, plans and management ,7,14. Sothe extent to which forests are studied and described in studies of human health;the extent to which patterns can be identified between forest variables and physiological health effects.The aim of this review was thus to analyze the available literature on forests and human health to assess:Guidelines for Systematic Review and Evidence Synthesis in Environmental Management [Studies published before May 2019 were systematically reviewed following the nagement . Previous reviews were analyzed to identify relevant terms for configuring a Boolean search: Cho et al. 2017), Hansen et al. (2017), Meyer and Bürger-Arndt (2014), Oh et al. (2017) and Song et al. 2016) [ 6,9,13,,13,17. T, Hansen The keywords identified were combined with Boolean operators considering the three blocks mentioned above to generate the following search: ((forest OR forests OR forested OR woodland* OR jungle OR rainforest) AND  AND  NOT ) OR (shinrin-yoku OR shinrinyoku OR “shinrin yoku”).Shinrin-yoku is commonly understood as being in the forest environment and taking in the atmosphere of the forest in expectation of potential curative or therapeutic effects [ effects . This teThe Web of Science (WOS) and PubMed were selected for the systematic search. Terms were searched in WOS for topic without any other filter, but terms were searched in PubMed for all fields containing the terms and sorted by clinical studies and trials, comparative and observational studies and randomized control trials. The results from PubMed were also filtered by experiments only with humans and articles only written in English. The combined searches identified 3445 articles . Titles,experiments with a real-life exposure to forests;experimental studies with humans;articles containing quantitative objective measurements of physiological health variables.Articles were examined for title, abstract, keywords and methods, if needed. Inclusion considered the following criteria: Laboratory experiments and studies with only virtual images or videos; studies with qualitative, self-rated or self-perceived health issues; reviews and articles using broad-scale spatial data were all excluded. In this study forests are considered as areas covered by trees which are not predominantly under agricultural or urban land use. Therefore, we did not include studies conducted in plantations or urban forests. A total of 62 articles were ultimately included in the analysis. Three authors gathered the information from each article using a codebook, with consensual definitions and consultation to resolve differences. Inter-code consistency was tested by each author by reviewing three random articles. Details of variables were collected from each study based on article basics, exposure characteristics, forest descriptions and health outcomes. Items from each group are presented below.-authors, year of publication, title, country where the study was conducted, number of participants and study design. This last item, concerning the methodology used in the study, was further classified into three categories: before-after (B-A) studies, control trials (CTs) (randomized or not) and comparative studies (when different forests or types of groups were compared). This distinction was made to better register the records of health variables for a more comprehensive analysis. Effects before and after forest exposure, between urban and forest environments or even between forest types could thus be compared.Article basics: -exposure type classification considering three levels: (a) passive exposure ; (b) active exposure  and (c) pro-active exposure . Exposure time was also recorded and ranked in minutes (≤60 min), hours (≤24 h), days (≤365 days) and years (>1 year).Exposure characteristics: we suggested the following -forest type (taken from the species composition or dominance if not explicitly mentioned in the text), abiotic variables measured , general forest description , forest species described (tree species composition), forest age, management strategy (any information about the management regime develop in the studied forest), forest variables described  and forest variables measured . All data were gathered into these representative categories of the detail degree of description for a forest ecosystem. We assumed forest type as the broadest description of a forest, and the measurement of a particular forest variable as the most accurate and precise approach for describing a stand.Forest descriptions: forest information from the articles were gathered and sorted into eight categories: -increases , decreases , non-significant (NS) results after the trial and mixed effects (when changes were significant but increased for some participants while decreased for others). Similarly, the effect of a forest was assessed for CTs and classified as: Higher , Lower , Non-significant (NS) after the trial and Mixed effects (when changes were significant but were lower for some participants and higher for others). Significant levels were set at p < 0.05. Health variables were not registered if an article did not explicitly present statistical analysis of values before and after exposure or a comparison between the tested environments.Health outcomes: measured health variables were registered for each article. The effects of forests in B-A studies were assessed and classified at four levels: Descriptive and exploratory analyses were used to identify patterns among the data collected. We analyzed the frequency in which different forest variables were described in the existing literature sorting them out in categories according to the degree of detail description and produced summary statistics. We developed pivot tables to examine the relationships between forest and human health variables. These relationships were obtained only for the most commonly studied health variables registered in this review: blood pressure (diastolic and systolic), pulse rate and cortisol levels . These variables were also surveyed in two recent reviews, which found strong correlations with exposure to forest ecosystems ,8. An overview of the selected articles’ basics is presented in We found no consistent and uniform consensus between the descriptions of the forest ecosystems and human health . The forAmong the 62 studies, 103 health variables were recorded , includiNearly 55% of the studies provided information about the potential effect of forest type on blood pressure . Mixed fContrasting these records with CTs measurements in the cities  indicateThe effects on PR are presented in Few of the B-A studies reported cortisol levels. Cortisol measurements were reported for only two forest types: broad-leaved and mixed forests . The B-AThis systematic review was conducted to analyze the details of forest descriptions among studies of these ecosystems’ potential effects on human health and to identify patterns between forest and health variables, when possible. The number of participants, exposure time and type were highly variable among the 62 selected articles. The impacts on health were generally positive, while a considerable number of studies showed non-significant results. Most studies addressed physiological health variables during short periods of time in small samples of healthy populations mainly focusing on parameters with low specificity for clinical decisions. This review found that: (a) 19.35% of the articles lacked any forest description; (b) the descriptions in the articles that did provide this information were highly heterogeneous and (c) no pattern was identified in the data between health variables from the three most studied variables  and the basic level of forest description considered: forest type. From the total, 66.13% of the articles described the forest type or procured information to estimate it. Other reviews analyzing the link between nature, forests and human health have also reported this scarcity of confounding factors description of forest environments ,78, perhSome studies have begun to address the relevance of forest characteristics to human health. Saito et al. (2019) assessed the differences in various health variables between exposure to an unmanaged forest and a managed forest . Blood p3, respectively) [In regard to forest variables, some studies have identified BVOCs as a key element in these ecosystems ,25,80. TThis review could not find any pattern in the data between the three most studied health variables  that could account for the basic level of forest description considered: forest type. These findings are similar to those of other reviews that considered the effects of exposure to nature on mental health  or the bThe limitations of language may have been important when developing the systematic search because many of the publications were in Asian languages. The high variability of participant number, exposure time, forest type and study design may have induced analytical biases among the data collected. The assumption of forest type when tree composition or dominance were provided may also have added biases to the analysis due to the scarcity of basic forest descriptions. We were also conscious of the challenge to identify patterns and relationships by analyzing studies of real-life exposure to natural forested areas where subject reactions and health effects may be influenced by different sensory stimuli, seasonal variabilities, meteorological conditions, exposures and performances of the activities conducted or other inputs not previously considered. Only three health variables among the studies could be screened. Nevertheless, other health variables not considered in this review may also be relevant to human health in future studies. These in situ studies nevertheless provided relevant data for understanding the connection between human health and forest ecosystems, even though the effects of forests on humans may presumably be derived from different inputs, components and characteristics of forest environments.This systematic review underlines the lack of forest variables descriptions among studies of forests and human health and highlights that it is still premature to make any sort of conclusions with respect to data patterns due to the high heterogeneity within the studies performed so far. Furthermore, no consistent relationships between forest type and health variables  could be identified from the existing literature.


Household air pollution (HAP) caused by the combustion of solid fuels for cooking and heating is responsible for almost 5% of the global burden of disease. In response, the World Health Organisation (WHO) has recommended the urgent need to scale the adoption of clean fuels, such as liquefied petroleum gas (LPG), in low and middle-income countries (LMICs). To understand the drivers of the adoption and exclusive use of LPG for cooking, we analysed representative survey data from 3343 peri-urban and rural households in Southwest Cameroon. Surveys used standardised tools to collect information on fuel use, socio-demographic and household characteristics and use of LPG for clean cooking. Most households reported LPG to be clean (95%) and efficient (88%), but many also perceived it to be expensive (69%) and unsafe (64%). Positive perceptions about LPG’s safety , cooking speed , affordability , availability , and its ability to cook most dishes , were significantly associated with exclusive LPG use. Socio-economic status (higher education) and household wealth (higher income) were also associated with a greater likelihood of LPG adoption. Effective strategies to raise awareness around safe use of LPG and interventions to address financial barriers are needed to scale wider adoption and sustained use of LPG for clean cooking, displacing reliance on polluting solid fuels. These ao health . In 2017o health . The Wor2.5 or to reducing the harms associated with HAP [To achieve those targets, much interest arose in burning biomass more cleanly using cookstoves with improved combustion and/or venting through chimneys. This was summarised in a systematic review and meta-analysis (SRMA) of real-life effectiveness of “improved” stoves and clean fuels in reducing HAP . Howeverwith HAP ,7,8. Accwith HAP ,10,11. Twith HAP . In addition to the health impacts of HAP, there are important implications for the climate, with emissions from solid fuel combustion, including black carbon and greenhouse gases, contributing to global warming . ReliancTo inform national policies concerned with scaling LPG in Cameroon, the LPG Adoption in Cameroon Evaluation (LACE) studies were launched in 2016, coinciding with the announcement of the national LPG Master Plan. The studies aimed to identify barriers and enablers to using LPG as a household fuel and to test community-based interventions to address these barriers. A publication of findings from the LACE surveys of two communities in Southwest Cameroon found that education, household wealth and socio-economic status were all predictors of LPG adoption and exclusive use . A furthThe current study aims to quantitatively summarise socio-economic and individual drivers of LPG adoption and sustained use as a clean cooking fuel in Southwest Cameroon. It builds on the results of the previous mixed-methods research in the region ,23 by utQuestionnaires for the quantitative surveys were developed using existing pre-validated questions  and new questions derived through expert consultation and subsequent piloting . The surveys included information on the demographic composition of each household, detailed primary and secondary fuel use, cooking behaviours and each respondent’s perceptions of LPG as a household fuel. These perceptions included speed, cleanliness, availability, affordability, safety, its ability to cook dishes and the ease of replacing cylinders, each of which were rated on a four-point scale (ranging from very good to very bad) . n = 707) and Botaland (n = 1059)) as part of an evaluation of microfinance to support LPG adoption. Further details of these two phases are shown in The study population consisted of three peri-urban communities and one rural community in the anglophone region of Southwest Cameroon . The surveys were conducted in two phases during the LACE studies. Phase 1 (LACE-1) was conducted in 2016 and involved 1577 households from two health districts in the Southwest Region of Cameroon . Initial descriptive findings relating to characteristics of the survey population and fuel use have been published by Pope et al. . Phase 2All the surveys were conducted by eight trained fieldworkers once the communities had been sensitised and enumerated. For each household in both phases, the main cook and/or household head was asked to complete the questionnaire (due to their direct involvement with the usage and purchase of household fuel). These were administered in English, or when appropriate, in the local dialect (Pidgin). Written informed consent was obtained from participants at the point of questionnaire delivery, and data were anonymised at collection. Ethical approval was granted by the Cameroonian ethics committee , and subsequently from the University of Liverpool’s ethics committee.Primary use of LPG fuel  was the main outcome of interest. Potential predictors of LPG use included the following variables: (i) socio-demographic, wealth and individual factors , (ii) household characteristics  and (iii) LPG perceptions . A descriptive comparison of LPG use by the predictor variables was summarised using appropriate hypothesis testing: categorical (chi-squared tests) and continuous  comparisons—a statistical significance value of 5% was used, with a Bonferroni correction being applied for multiple comparisons. Unconditional logistic regression was used to summarise the relationship between LPG use (dependent variable) and socio-economic, wealth, individual and household characteristics and LPG fuel perceptions (independent variables). Associations were summarised through odds ratios and 95% confidence intervals. The outcome (LPG use) was classified as “any LPG use” (households using LPG as either their primary or secondary cooking fuel) and “exclusive LPG use” (households reporting using LPG as their only cooking fuel). To identify factors most strongly associated with LPG use, multivariable logistic regression analysis was conducted, including all factors found to be significantly associated with LPG use in univariate analysis. To summarise the predictive strength of the final model, a Hosmer–Lemeshow goodness of fit test was conducted. All analyses were conducted using Stata v14  .Survey data were obtained from a total of 3343 households; 243 rural households from Buea and 3100 peri-urban households from Limbe . Response rates were high (>90%) when households were resident at the time of visit, possibly resulting from the process of sensitising communities, facilitated by community chiefs and town criers. In rural Buea, only approximately half the available homes were surveyed due to the difficulty of finding people at home during the survey period . n = 1727; 52%), median age 36 years. The majority reported being married or in a partnership  and having completed primary  or secondary  education. In peri-urban areas, people typically rented their houses , whereas in the rural community, home ownership was more common . Almost two thirds of homes did not have a flushable toilet  or access to piped water , even though approximately half  of household incomes exceeded the national average of 50,000 CFA  (83 United States Dollars (USD)) per month .The characteristics of the participants who took part in the surveys are shown in p < 0.0005), older  and single . They were also less likely to have received a secondary education . Rural households also typically had lower levels of income and asset ownership compared to peri-urban households. They were less likely to earn above the poverty threshold of 25,000 CFA per month ; were less likely to be paid in cash ; and were less likely to own a flushable toilet , have piped water  and have access to a car .Compared to peri-urban household heads, rural household heads were more likely to be male  and wood , but other primary fuels included kerosene , charcoal , sawdust , piped gas  and electricity . As one would expect, rural homes were significantly more likely to use wood as their primary cooking fuel  and less likely to use LPG  given the availability of freely gathered wood in the rural community. Reported primary and secondary fuels used for cooking are shown in Most households (70%) used multiple fuels for cooking (fuel stacking). The most common fuel combinations were LPG and wood (57%), LPG and charcoal (18%) and kerosene and wood (10%). Amongst households using LPG as either a primary or secondary cooking fuel, the majority (81%) exhibited fuel stacking behaviour. A similar pattern was seen across all four communities see .n = 2808; 95%), obtainable , cooked most foods  and did so quickly . However, a high proportion of respondents reported concerns over the safety of LPG. Overall, more than two thirds of people  reported thinking that the fuel was either dangerous or very dangerous. These concerns could present a significant barrier to LPG adoption, although interestingly, a large proportion of LPG users  and exclusive LPG users  also reported thinking that it was unsafe while continuing to use it regularly. In addition to concerns about safety, many respondents expressed negative views relating to the cost of LPG. The majority of people reported that LPG refills were either expensive or very expensive . This view was most apparent amongst those who reported that they did not use LPG , although it was also common amongst any LPG users  and exclusive LPG users .Perceptions of LPG as a cooking fuel are shown in Perceptions of LPG differed significantly by socio-demographic group . In geneTo investigate how perceptions of LPG as a cooking fuel might be related to adoption and exclusive use, opinions of LPG in terms of its efficiency, safety, cleanliness, availability, cost and ability to cook most dishes were stratified according to LPG use . PerceptRespondents who perceived LPG to be safe were almost twice as likely to report using LPG , compared to those who reporting thinking it was dangerous  . SimilarPerceptions of LPG appeared to play a more important role in determining whether respondents used LPG exclusively compared to whether they used it at all. Positive perceptions of LPG in all categories (apart from cleanliness) significantly increased the likelihood of exclusive LPG use . RespondAssociations between socio-economic factors and LPG adoption or exclusive use were assessed in peri-urban households . Older hReporting of any use of LPG significantly increased with rising income . Those eIncreasing family size had no effect on any LPG use, but was significantly associated with exclusive use such that peri-urban households containing more than six people were 92% less likely to use LPG exclusively compared to those with 1–3 people . Similarly, although livestock ownership was not related to any LPG use, households who owned their own livestock were 87% less likely to use it exclusively  compared to those without.p = 0.3811; R-square = 0.343). For “exclusive use of LPG,” younger age, being single, larger household size (number of people resident), overcrowding, a cash income, owning livestock and cooking indoors were all independent predictors .Two multivariable models were developed for each outcome; (i) any use of LPG and (ii) exclusive use of LPG, based on the sets of covariates significantly associated with each outcome in univariate analysis . For “anThis study utilises a unique dataset comprising results from over 3300 peri-urban and rural households in the Southwest Region of Cameroon. We explored perceptions of LPG as a clean cooking fuel and identified factors affecting its adoption and exclusive use. The findings are relevant for programs designed to scale widespread adoption of clean household energy.n = 38) reported using LPG as a primary cooking fuel with most (81%) using freely gathered wood. The wider use of LPG for clean cooking in peri-urban/urban compared to rural LMIC settings has been documented in the literature [We found that there is widespread use of LPG as a primary cooking fuel (56%), although mainly within peri-urban settings. In the rural context, only 16% of households  used more than one fuel for cooking. Of those households reporting use of LPG for cooking (as either a primary or secondary cooking fuel), four-fifths (81%) used it alongside a polluting solid fuel . It is well established that this “fuel stacking” is the norm for many households across SSA, Asia and Latin America ,52,53,54The socio-economic determinants of new adoption of clean household energy are well documented ,30,31,59The drivers for transition to clean household energy are complex. In their systematic review, Puzzolo et al.  identifiOther studies from a variety of countries and settings have found concerns expressed by households over the safety of LPG as a cooking fuel, including studies from Mozambique, Peru, Cameroon and Nigeria ,46,54,60We are confident that the surveys are representative of our study population in Southwest Cameroon due to the large sample size and high response rate. However, the number of households surveyed in rural areas was much smaller than the number in peri-urban areas, making the results more applicable to peri-urban settings. In addition, the study region generally has lower levels of poverty, higher levels of education and a greater proportion of homes with access to piped water compared to the rest of the country. This greater affluence in the study’s context corresponds to a greater proportion of households using LPG than the national average due to wider access to the fuel and affordability.One unique facet of the study was the enquiry about perceptions of LPG as a cooking fuel in addition to actual use of LPG as a primary or secondary fuel. This allowed a comparison of safety concerns  by amount of LPG use, with residual concerns over safety still being reported in a notable proportion of exclusive users.The cross-sectional nature of the study means that it is not possible to comment on the temporality of findings, although reported associations between socio-demographic and economic characteristics with use of LPG for clean cooking are consistent with observations from the literature. Of added value from this study is that, whilst the evidence for the association of these characteristics with adoption (or new use) of LPG confirms the findings from other studies in LMIC settings, the observation for the impact of the factors on exclusive LPG use is relatively unique. Whilst policies by the Government of Cameroon in relation to the National LPG Masterplan will be focused on increasing adoption of LPG, the benefits of clean cooking through reductions in household air pollution will only be experienced if the fuel is used in a sustained way and almost exclusively. To support this, it is crucial that LPG supply is consistent and reliable, and that the cost implication of using LPG for foods with long cooking durations is addressed.1.Addressing concerns around safety through effective messaging and education around LPG as a safe household fuel, including demonstration of its correct use to new users and careful inspection of LPG equipment;2.Addressing prohibitive costs of switching to LPG as a new cooking fuel through provision of financial assistance (microloans) to acquire the LPG equipment;3.Addressing concerns over the affordability of refills through maintenance of the fixed LPG subsidy (currently set by the Cameroon government at 6500 CFA (11 USD) for a 12.5 kg refill) and transport price equalization to regulate consistent pricing of LPG fuel in more remote areas.The LACE studies were developed alongside publication of the Cameroon National LPG Masterplan by the Ministry of Energy and Water (MINEE) to provide an evidence base for policies facilitating community transition from traditional use of polluting solid fuels to clean cooking with LPG. Results from this cross-sectional evaluation highlight some of the barriers to both adoption and sustained use of LPG for cooking that are amenable to strategic decision making for policy development. These include:The results for this cross-sectional analysis have identified a complex range of factors that influence both the adoption and exclusive use of LPG and highlight the need for a multi-faceted approach to policy in scaling its use for household energy . A “wholThis study has used extensive cross-sectional survey data from rural and peri-urban communities in the Southwest Region of Cameroon to explore current fuel use practices and identify factors that affect both adoption and more exclusive use of LPG for clean cooking. In Southwest Cameroon it is evident that use of LPG as a primary cooking fuel is widespread , reflecting the relatively mature LPG market in the region. Despite this, exclusive cooking with LPG was found to be rare, with concurrent use of other fuels  being relatively common. Predictors of adoption and sustained use include a higher education, rising income and younger age, whereas rural location, problems with availability, increased fuel costs and larger household size (increasing number of residents) appear to inhibit use of LPG.The positive attributes of LPG were clearly expressed by study participants, with the majority reporting LPG as a convenient, clean and effective cooking fuel; however, a significant proportion of both users and non-users reported the fuel to be both unsafe and expensive. Familiarity with the fuel lessened these negative perceptions, with households reporting exclusive use of LPG being more likely to express positive views about it (compared to mixed and non-LPG users). Positive perceptions about LPG were particularly important for increasing the likelihood of exclusive use. Negative perceptions of LPG in terms of safety and cost will reduce the effectiveness of policies to effectively scale adoption and sustained use of the fuel for cooking. LPG is an inherently safe fuel when used correctly in a well-regulated market, wherein marketers take legal responsibility for maintaining the safety of LPG supply and cylinders (such as that in Cameroon). Education on safe cooking with LPG is likely to be an effective strategy to accompany other policies in order to scale adoption of the fuel in Cameroon to aspirational target levels  . The issBeyond the national context for Cameroon, the results of this study are likely to be relevant to other Sub-Saharan African contexts, wherein there is an aspiration to scale adoption of LPG for clean household energy to achieve SDG 7 , while also contributing to reducing (i) the substantial burden of disease from household air pollution from combustion of solid fuels/kerosene and (ii) deforestation.