This study validates the relationship between community-level sports group participation and the frequency of leaving the house and transtheoretical model stages of behavior change for exercise among older individuals who did not participate in a sports group. We used cross-sectional data from the 2016 Japan Gerontological Evaluation Study. The proportion of sports group participants at the community level was calculated using the data from 157,233 older individuals living in 1000 communities. We conducted a multilevel regression analysis to examine the relationship between the proportion of sports group participants and the frequency of leaving the house (1 day/week or less) and the transtheoretical model stages of behavior change for exercise. A statistically significant relationship was observed between a high prevalence of sports group participation and lower risk of homeboundness (odds ratio: 0.94) and high transtheoretical model stages  as estimated by 10 percentage points of participation proportion. Older individuals, even those not participating in a sports group, living in a community with a high prevalence of sports group participation are less likely to be homebound; they are highly interested and have numerous opportunities to engage in exercise. Older individuals engaging in sports and exercises while participating in groups are at lower risk of functional disability, depressive symptoms, and falls than those engaging in sports and exercises alone without participating in such groups ,2,3. TheCivic participation, such as sports group participation, is a component of social capital . One of This multilevel cross-sectional study examines whether the frequency of leaving the house was maintained and the transtheoretical model stages of behavior change for exercise were high among older individuals, even those who do not participate in the sports group, living in a community with numerous sports group participants.We used cross-sectional data from the Japan Gerontological Evaluation Study (JAGES), which is an ongoing cohort study exploring social, environmental, and behavioral factors correlated with health loss, particularly functional decline or cognitive impairment, among individuals aged 65 years or older . We mailThe participants were assessed for the frequency of leaving the house . The choices for the answers were as follows: ≥4 days/week, 2–3 days/week, 1 day/week, 1–3 days/month, a few times/year, and zero. We defined going out 1 day/week or less as mostly homebound ,18, and The transtheoretical model stages of behavior change assess an individual’s readiness to act on a healthier behavior . In thisThe participants were assessed for the frequency of sports group participation. The choices for the answers were as follows: ≥4 days/week, 2–3 days/week, 1 day/week, 1–3 days/month, a few times/year, and zero. We defined participating 1 day/month or more as participation in a sports group ,22, and 2 of inhabitable area and mean annual household income for each community area were calculated and categorized into the following quartile categories: ≥10,000; 7000–9999; 2500–6999; and <2500 individuals per km2 and JPY ≥2,713,000; JPY 2,468,000–2,712,999; JPY 2,250,010–2,467,999; and JPY <2,250,010, respectively.We evaluated confounding variables between community-level sports group participation and individual-level health status . Data onB) and 95% CI for the transtheoretical model stages of behavior change for exercise. The OR and B of community-level sports group participation was estimated as a 10-percentage point change in aggregated sports group participation. The following three models of analysis were used: the null model, crude model including community-level sports group participation, and fully adjusted model . We calculated the proportional changes in the variance of the crude and fully adjusted models to the null model to estimate how much the community-level variances of the frequency of leaving the house and transtheoretical model stages of change were explained by the exposure and covariates. Furthermore, we conducted a subgroup analysis by age groups  to investigate whether the relationships were consistent or not. Analyses were performed using Stata/MP 14.2 .This analysis was conducted from January 2019 to March 2019. The multilevel analysis framework assumes that the health outcome of an individual partly depends on the community in which an individual lives. Multilevel models estimate the variations in outcome between communities (random effects) and the effects of community-level variables while adjusting for individual- and community-level characteristics (fixed effects). Multilevel logistic regression analysis was conducted to calculate the odds ratio (OR) and 95% confidence interval (CI) for being mostly homebound, and multilevel mixed-effects linear regression analysis was performed to calculate the partial regression coefficient (n = 23) or extent of sports group participation  or those who participated in a sports group 1 day/month or more . Individuals with missing information on each outcome were excluded as well. Finally, 89,847 participants were considered analytic participants for the frequency of leaving the house analysis. With regard to the transtheoretical model stage analysis, the analytical sample comprised 10,487 participants because the question item was distributed to one-eighth of the participants who were randomly allocated.n = 4356) were at the precontemplation stage, whereas 20% (n = 2260) were at the action or maintenance stage. B: 0.06; 95% CI: 0.01–0.12 in the adjusted model), and the community-level variance decreased by 23.1% and 38.5%, respectively. To the best of our knowledge, this is the first study to assess the contextual relationship between community-level prevalence of sports group participation and health behavior in older individuals, particularly those who do not participate in a sports group. A 10-percentage point increase in community-level sports group participation was associated with a 6% reduction in the risk of being homebound and a 0.06 higher in the transtheoretical model stages of behavior change for exercise after adjusting for potential confounders. These favorable associations can occur at any age group in the older population.Social contagion might be considered a pathway that confirmed the results of this study supporting our hypothesis. Sometimes the behavior spreading via the network can promote healthy lifestyle changes  ,24. In rAnother possible pathway is collective efficacy, which is the group-level analog of the concept of self-efficacy and refers to the ability of the collective to mobilize to undertake a collective action ,26,27. FThe transtheoretical model of behavior change is an integrative theory of therapy providing strategies or processes of change to guide an individual . The strThe study strength is its large, nationwide, population-based sample enabling community- and individual-level multilevel analyses for clarifying the contextual relationship of sports group participation limited only to non-participants in a sports group. However, this study had several limitations. First, reverse causality could occur because of the nature of the cross-sectional design, and longitudinal studies must be conducted to resolve this limitation. Second, selection bias might have affected the results due to the relatively low response rate at 70.2%. According to our previous study, the response rate and percentage of sports group participants with older age were significantly lower than those with younger age . TherefoOlder individuals, even those who do not participate in a sports group, living in a community area with a high prevalence of sports group participation were less likely to be homebound and have higher transtheoretical model stages of behavior change for exercise than those living in an area with a low prevalence of participation. Promoting sports groups in a community may be an effective population-based strategy for increasing the frequency of leaving the house and enhancing interest in and providing opportunities to engage in exercise and sports even for non-participants in a sports group. A policy to increase sports groups, giving priority to communities where many older individuals with health problems live, may be effective.


In the wake of COVID-19, university students have experienced fundamental changes of their learning and their lives as a whole. The present research identifies psychological characteristics associated with students’ well-being in this situation. We investigated relations of basic psychological need satisfaction  with positive emotion and intrinsic learning motivation, considering self-regulated learning as a moderator. Self-reports were collected from 6,071 students in Austria (Study 1) and 1,653 students in Finland (Study 2). Structural equation modeling revealed competence as the strongest predictor for positive emotion. Intrinsic learning motivation was predicted by competence and autonomy in both countries and by relatedness in Finland. Moderation effects of self-regulated learning were inconsistent, but main effects on intrinsic learning motivation were identified. Surprisingly, relatedness exerted only a minor effect on positive emotion. The results inform strategies to promote students’ well-being through distance learning, mitigating the negative effects of the situation. To contain the spread of the COVID-19 pandemic, many countries instituted temporal closures of higher education institutions in March 2020. According to Resilience, the capacity to overcome hardships, to flourish in the face of challenges , and to Beyond the economic return to individuals and to society as a whole e.g., , higher Distance education, or distance learning, is understood as an umbrella term, as its implementation varies greatly from case to case. A general characteristic is, however, the lack of physical presence and the lesser extent of informal discourse and spontaneous interaction. This bears the risk of transactional distance, a communication gap that creates negative emotions, gaps in understanding, and misconceptions  and Finland (Study 2), the present research takes a multistudy approach. To examine whether findings are consistent in both countries, we first collected data in Austria and then conducted a follow-up in Finland.SD = 7.52, Mdn = 23.00, range = 18–71). Data were collected via online questionnaires in spring 2020. Before being forwarded to the items, participants were informed about the study’s goals; approximate duration of the questionnaire; inclusion criteria for participation, that is, attending university in the respective country; and the complete anonymity of their data. All students participated voluntarily and only those who gave active consent were included in the dataset.The overall sample comprised 7,724 university students  with a mean age of 25.76 years . The students were from higher education institutions all over Austria. Data were collected from April 7 to April 24. We distributed the link to the online questionnaire by contacting diverse stakeholders such as university rectorates and higher educational networks. Additionally, the Federal Ministry of Education, Science, and Research published the study link and recommended participation on its website.The sample comprised 6,071 university students  with a mean age of 25.02 years . The students were from the University of Helsinki, Finland. Data were collected from April 29 to June 2, 2020. The link to the online questionnaire was distributed via faculty email lists and the University of Helsinki’s social media channels.The sample comprised 1,653 university students  with a mean age of 28.49 years  to 5 (strongly disagree). Participants were instructed to respond to items with respect to the current situation, that is, learning from home due to the COVID-19 pandemic. In order to simplify the interpretation of results, all analyses were conducted with recoded items so that higher values reflected higher agreement with the statements.Due to the novelty of the COVID-19 situation, we adapted existing scales or developed new items to suitably address the current circumstances. To ensure content validity of the measures, we revised the items in a first step based on expert judgments from members of our research group. In a next step, the questionnaire was piloted with cognitive interview testing. Finally, the original German questionnaire was translated into Finnish using the translation–back-translation method . To ensuCompetence was measured with three items adapted from the Work-related Basic Need Satisfaction Scale .Relatedness was measured with three items inspired by the Work-Related Basic Need Satisfaction Scale , and the root mean square error of approximation (RMSEA). Following N > 300), declines in CFI > .01 and increases in RMSEA > .015 indicate meaningful model fit changes, making the assumptions of measurement invariance not tenable. For all three models, which were measured on 5-point Likert-type scales, the robust maximum likelihood estimator was used for the CFAs.Second, we tested for measurement invariance across countries of data collection. CFAs for the three basic needs, self-regulated learning, and the outcomes were set up to investigate the dimensionality of the scales. We tested for measurement invariance  across countries by calculating a set of increasingly constrained CFAs. While configural invariance tests whether the same factor structure is valid for each group, metric invariance indicates that participants in both countries attribute the same meaning to the latent constructs. Finally, if the assumption of scalar invariance holds, the meaning of the levels of the underlying items is equal in both groups . We follThird, we set up two models to test the main effects and the latent interactions in both studies. Model 0 tested the main effects of competence, autonomy, relatedness, and self-regulated learning on positive emotion and intrinsic learning motivation. In Model 1, latent interactions between competence and self-regulated learning as well as between autonomy and self-regulated learning were added, as appropriately specified latent-interaction models include both main-effect variables and the product term . Additiocomp = 3.94 and VIFauto = 3.40. Generally, VIFs higher than 5 are considered to indicate potential difficulties in separating out the independent contribution of the variables concerned  for the two variables, yielding VIFoncerned . Other aoncerned . If the p < .001, RMSEA = .050, CFI = .959, and Study 2, χ²(120) = 515.09, p < .001, RMSEA = .045, CFI = .968. The tests for measurement invariance showed that configural and metric invariance could be established for all variables based on The CFAs revealed excellent fit indices for all scales for both Study 1, χ²(120) = 1963.24, 1 and Model 02) for the two studies. Model estimation for the main effect models revealed that competence positively predicted both outcomes in both studies. Autonomy positively predicted intrinsic learning motivation in both studies, and positive emotion in Finland. Albeit the small effect size, autonomy was identified as a negative predictor for positive emotion in Austria. In this regard, however, it must be noted that competence and autonomy were highly correlated in the Austrian sample. Therefore, the parameter estimates for the unique effects of competence and autonomy on the outcomes might not be reliable. Relatedness positively predicted positive emotion in both studies, and intrinsic learning motivation in Finland only, with small effect sizes, respectively. Self-regulated learning negatively predicted positive emotion with a small effect in Austria, and positively predicted intrinsic learning motivation in both studies  = 472.778, p < .001. This result indicates that the null model represents a significant loss in fit relative to Model 11. Model 11 should therefore be kept for Study 1  were added to Model 0 for both studies, resulting in Model 1dy 1 see .SE = 0.04, p = .047 (see Model 12 in D(4) = 16.108, p < .005, indicating a better relative fit for Model 12. Model 12 is therefore kept for Study 2 . For the moderation effect of self-regulated learning on the relationships between competence and intrinsic learning motivation, and between autonomy and intrinsic learning motivation, we found no significant effects (Hypotheses 2c and 2d). Although the interactions were not consistently identified, it should be noted that the main effects of self-regulated learning on intrinsic learning motivation were significant with small to moderate effect sizes in both studies. This speaks in favor of the relevance of self-regulated learning for enabling intrinsic learning motivation.cocooning had a revival, referring to staying inside one’s private home, shielded from perceived danger, instead of going out  could be used to reflect on learning processes, successes, as well as struggles and to promote cohesion within the group. For further strategies to promote the development of an online community, see, for example We consider the high explanatory power of our models, with proportions of explained variance ranging from 39% to 61%, and the large sample size as substantial strengths of our research. Moreover, we followed a multistudy approach and tested our assumptions in samples from two different countries. The results are further supported by the identified configural and metric measurement invariance, indicating that the same factor structure and the same meanings attributed to the latent constructs can be assumed across both countries of data collection.Despite these noteworthy strengths, the present research is limited in some respects. First, the results rely on self-reports. While this is the usual practice for most of the examined constructs, there are concerns about the validity of self-report tools for assessing self-regulated learning e.g., . Second,Considering these limitations, we recommend that follow-up studies incorporate further informants  and other methods of data collection  to obtain a more comprehensive picture. This especially relates to the role of self-regulated learning and to the further investigation of the surprisingly low association between relatedness and positive emotion. Future research should also consider different approaches of sample recruitment to ensure a better representation of the population. Particularly, longitudinal studies should be carried out to further substantiate the evidence for the large effects found. With regard to the delivery of distance education, it should be considered to evaluate concrete design options such as modality, pacing, instructional practices, role of assessments, and feedback see  and to iThe present research highlights the relevance of perceived competence, autonomy and self-regulated learning for university students’ well-being in times of unplanned and involuntary remote studying. The results also indicate a potential relevance of relatedness for intrinsic learning motivation. The requirement for higher education institutions is to explicitly promote these identified dimensions. To take advantage of the potential, distance learning should be designed in a way that maximizes the strengths and constrains the weaknesses of distance education.


Breast cancer is the most prevalent cancer in women. To date, regional differences in breast cancer risk factors have not been identified. The aim of our review was to gain a better understanding of the role of risk factors in women with breast cancer in Asia. We conducted a PubMed search on 15 March 2016, for journal articles published in English between 2011 and 2016, which reported data for human subjects in Asia with a diagnosis of breast cancer. Search terms included breast neoplasm, epidemiology, Asia, prevalence, incidence, risk and cost of illness. Studies of any design were included, except for review articles and meta-analyses, which were excluded to avoid duplication of data. No exclusions were made based on breast cancer treatment. We reported the results using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A total of 776 abstracts were retrieved. After screening against the eligibility criteria, 562 abstracts were excluded. The remaining 214 abstracts, which were published between 2013 and 2015, were included in this review. Results were summarized and reported under three categories: incidence, prevalence or outcomes for breast cancer in Asia; modifiable risk factors; and non-modifiable risk factors. We found that the increased risk of breast cancer among participants from Asia was associated with older age, family history of breast cancer, early menarche, late menopause, high body mass index, being obese or overweight, exposure to tobacco smoke, and high dietary intake of fats or fatty foods. In contrast, intake of dietary fruits, vegetables, and plant- and soy-based products was associated with a decreased breast cancer risk. While based on limited data, when compared to women from the United States, women from Asia had a decreased risk of breast cancer. This review of 214 abstracts of studies in Asia, published between 2013 and 2015, confirmed the relevance of known non-modifiable and modifiable risk factors for women with breast cancer. The most recent data from the World Health Organization (WHO) shows that breast cancer (BC) is the most prevalent cancer in women, with an incidence of 1.7 million cases in 2012 . It is the fifth leading cause of death from cancer overall . The incidence is similar in regions identified by the WHO as more- and less-developed, at 13%  and 11%  respectively . WHO figures from 2012 estimate the international 5-year prevalence for BC at 6,232,000; by region (as defined by WHO) the rate in South-East Asia is 735,000 compared to 1,936,000 in Europe and 1,618,000 in the Americas .Identified risk factors for BC may be non-modifiable such as sex, age, genetic characteristics including family or personal history of BC, ethnicity, and early menarche or menopause. Modifiable risk factors, usually associated with lifestyle factors, can include alcohol consumption, excess weight or obesity, physical inactivity, parity, and use of some medications, such as oral contraceptives .Despite these associations, women with risk factors for BC may never go on to develop BC and many women with BC have no known risk factors. Therefore, it is difficult to definitively determine the contribution of individual risk factors to the development of BC . To date, regional differences in BC risk factors have not been identified. The aim of our review was to gain a better understanding of the role of risk factors in women with BC in Asia.We performed a systematic review of the current body of evidence available through PubMed. The search was conducted on 15 March 2016. Medical subject headings (MeSH) search terms used included: breast neoplasm, epidemiology, Asia, prevalence, incidence, risk and cost of illness. The search was limited to human studies, published in English between 2011 and 2016. Studies were included in our review if the participants had BC of any age, histopathology, grade or stage, and received treatment of any type; studies needed to report information on epidemiology, prevalence, incidence, risk factors, and cost of illness. Our review included all study designs, except for review articles and meta-analyses, which were excluded to avoid duplication of data. Studies were only included if they reported data from countries within South East Asia, Far East Asia, or Western Asia excluding the Middle East. Articles were excluded if their primary objective was to examine the correlation of BC to other types of cancer or to examine surgical treatments for BC. Our search identified 783 articles; seven articles were excluded due to no abstract being available. We did not find any articles published in 2016. To reduce the volume of data identified in our search, only articles published within the previous three years (2013–2015) were included. This resulted in 169 eligible articles being excluded based on publication date (2011 and 2012). After the exclusion of duplicates and articles that did not meet the inclusion criteria, a total of 214 remaining articles were included in this review. The flow diagram of the literature selection process is presented in Results have been summarized and reported under three categories: incidence, prevalence or outcomes for breast cancer in Asia; modifiable risk factors; and non-modifiable risk factors. A summary of studies showing risk and protective factors influencing changes in BC risk is provided in Supplementary Incidence, prevalence or outcomes for breast cancer in AsiaBC was reported as the leading type of cancer in females in Japan , and China . In addition, the incidence of BC was shown to increase over time in China , India  and Thailand , although it was unclear if this was due to improved identification (i.e. screening and detection) or a true reflection of increased incidence. While BC incidence is predicted to increase in Hong Kong by 2025, mortality is projected to decrease from 9.3 to 8.6 per 100,000 women, respectively . This may be related to Hong Kong’s socio-economic development, and the improvements in survival may be due to treatment advancement and improved health service delivery . This is in contrast to China, where BC mortality increased over a 5-year period  between 2006 and 2010 . In one study from Malaysia, almost all  had an estimated 10-year risk of BC of less than 2% . In Korea, the rate of 5-year recurrence-free survival (RFS) was 90.8%, 10-year RFS was 81.9%, and 5-year overall survival (OS) was 94.6% . However other studies from Korea have reported the 10-year OS rate at 86.9%  and another at 61.4% . In Hong Kong and Vietnam, 5-year OS rates were 90.5% and 74%, respectively . The 5-year OS rate was similar in male BC patients from Hong Kong  . Supplementary Dietary FactorsDietary factors associated with increased BC risk included intake of total n-6 polyunsaturated fatty acids (PUFA) , vitamin D deficiency or insufficiency , high levels of serum cadmium , high intake of salt , sugar , meat , and saturated fat and oils . In women with BC, the trace elements, cadmium, magnesium, copper, cobalt and lithium, were found in high levels. This suggests a possible association between serum levels of trace elements and breast cancer risk, however, this requires further investigation and if confirmed, the modulation of trace elements may help to reduce breast cancer risk .High intake of dietary fiber was associated with decreased BC risk  along with high levels of α-carotene, β-carotene, β-cryptoxanthin, lutein/ zeaxanthin , and soy products or isoflavones  . In addiIn one study, the consumption of crucian carp was associated with increased BC risk, but total freshwater fish intake and consumption of black carp and silver carp were associated with decreased risk .Location of residenceLocation of residence were identified as a modifiable factor associated with increased BC risk and was identified in three papers . Results of the studies identified that living in an urban region of China  led to an increased BC risk. One paper noted a higher incidence of BC was correlated to higher population density, percentage of non-agricultural population, and second industry output; in contrast, incidence was negatively correlated with the percentage of population employed in primary industry . Other modifiable risk factors including active or passive smoking , high body mass index (BMI) , use of oral contraceptives , high perceived level of stress, and low level of physical activity  were discussed in the papers.BMI and physical activityA Thai study evaluated the relationship between BC risk and obesity and physical activity. The study found that being underweight at ages 10 and 20 years showed a reduced risk of BC in all women  and undertaking regular physical activity also showed a reduced risk . When reviewed by type of physical activity undertaken, those who had the highest levels of walking had the greatest reduction in risk  . Reproductive history and breastfeedingSeveral of the identified studies have investigated the effect of parity, abortion, age at pregnancy and history of breastfeeding on BC risk. In a Korean study, parity of five or more increased the risk of luminal A and B breast cancer  and an early age of first birth (less than 20 years) was associated with increased risk of luminal A BC recurrence . However, between one and three childbirths was associated with decreased risk of luminal A and B  . In India, women with BC, had a higher age at last child birth, lower mean duration of breastfeeding, and a higher number of abortions compared to women who did not have BC . In China, Wu et al., (2014a) reported reduced BC risk in parous women with 3 or more induced abortions or 3 or more induced abortions after first live birth, compared with parous women without induced abortion. Also in China, age over 25 years at first full-term pregnancy was associated with increased risk of BC, but a history of full-term pregnancy was associated with a decreased risk of BC . Huang et al., (2014) reported that among participants from China, later age at either first live birth, or at first pregnancy and last pregnancy were associated with increased BC risk . Among participants from Japan, BC was increased in women who performed mixed feeding  or feeding only with formula  compared with women who only breastfed .Breast cancer risk by geographic locationSeveral studies demonstrated differences in the prevalence and mortality associated with BC between nations in the Asian region, and significantly, differences within individual nations. Ginsburg et al., (2017) argue that the majority of women who die from BC live in low-income countries; this is in contrast to high-income countries where most women who are diagnosed with BC will survive. Malvia et al., (2017) indicate that the overall age adjusted rates for BC in India is as high as 25.8 per 100,000 women but lower than that of the United Kingdom . Indian mortality rates were reported at 12.7 per 100,000 women, which is comparable to the BC mortality rates in the UK . Further, disparities in BC risk and mortality can be seen within individual countries in Asia and within different regions within the same country. When Indian BC mortality rates are reported by region, some regions reported rates as high as 41 per 100,000 in Delhi and as low as 12.4 per 100,000 in Barshi rural region . Non-modifiable risk factors for breast cancer in Asia AgeIn India, the mean age of BC diagnosis was 53 years , and the median age was 45 years . This was similar to data from China, which indicated that the estimated risk of recurrent breast cancer increased with age (mean=46 years) . Peaks in age-specific breast cancer incidence were at 50–59 years and > 85 years . In a Thai study, incidence was projected to increase at a higher rate in women aged 50 years or over compared to those aged under 50 years (period to 2029) . Other studies have reported that benign breast disease was more likely to occur in women aged under 40 years, with BC more likely in women aged over 40 years . Family historyIn China , Pakistan , Hong Kong , India , and Korea , a family history of BC was associated with an increased risk of BC. In Hong Kong, risk of BC (in women with estrogen receptor-positive tumors) was higher in women with an affected mother  when compared to women with an affected sister  . A study in Nepal showed that family history of BC was evident in a higher proportion of women who developed BC aged less than 40 years (3%) compared with those aged 40 years or over (0.3%) .EthnicityRace/ethnicity and age-specific incidence rates have been shown to increase continuously until 80 years in white women from the United States (US), but plateau or decrease after 50 years in Asian women . A greater absolute risk for all BC subtypes has been found in women from the US National Cancer Institute’s Surveillance, Epidemiology, and End Results 18 registries database (SEER 18) compared to those from Malaysia . A further study demonstrated that, following adjustment for population structure, the median age of BC diagnosis was lower in China (50–54 years) than in the United States and European Union (55–59 years) . The authors suggest that this is due to racial differences in genetics and lifestyle and that BC screening programs should be commenced at an earlier age for Chinese women .Reproductive healthMenopausal status was associated with BC risk in studies conducted in Thailand , India , Pakistan , and Korea . Among participants from India, compared with controls, women with BC had a lower mean age at menarche  and a later age of menopause  . Lee et al., (2014) reported that late menopause was significantly associated with increased BC risk. In Korea, age at menarche and menopausal status or age at menopause were risk factors for BC . A second study in Korea confirmed the association with early age at menarche and BC risk, irrespective of tumor subtype . In Pakistan, older age at menopause was associated with increased BC risk . Hormone receptor statusIn China, estrogen levels and estrogen receptor-mediated serum bioactivity were higher in BC cases than controls . A study conducted in Malaysia found that the majority of BC cases were hormone receptor-negative . Conversely in a Korean study, 69.5% of BCs were hormone receptor-positive  and 44.6% of BCs were estrogen receptor-positive in an Indian study . Among participants from Korea, when estrogen receptor-positive/progesterone receptor-positive tumors were compared to estrogen receptor-positive/progesterone receptor-negative tumors, women with the latter were 4 years older at diagnosis and more likely to be postmenopausal .Genetic risk factorsSeveral of the studies investigated the association between gene polymorphisms and BC risk. In addition, there were also studies investigating the association between BC risk and DNA methylation , length of CAG repeats  , mitochondrial DNA content , mitochondrial D-loop insertions , and telomere length . The studies included in this review identified several associations between BC risk and genes that encode apoptotic regulators (e.g. BIM) , regulators of DNA stability or repair  , transcription factors  , estrogen-related enzymes or receptors   and cell surface glycoproteins, growth factors or their receptors  . Associations were also found for cytokines or regulators of cytokine signaling  , proteins involved in regulating circadian rhythm (e.g. PER3) , a ligand-gated ion channel (e.g. CHRNA9) , or transcription factors involved in embryonic stem cell proliferation, renewal, and pluripotency  . Other risk factors for breast cancer in AsiaIncreased BC risk was associated with insulin use for 3 or more years  among participants from Thailand ; polycystic ovary syndrome ; tonsillectomy ; sleep apnea ; multiple sclerosis among participants from Taiwan ; inflammatory bowel disease among participants from Asia ; women who had an organ transplant ; and diabetes among participants from China . In addition, a study conducted in China found that hypertension was observed in a higher proportion of BC patients with type 2 diabetes compared with non-diabetic participants with BC   demonstrating a link between breast cancer and other comorbidities. Another study conducted in China showed that premature ovarian failure was associated with decreased incidence of BC among postmenopausal women . Higher levels of education have been linked to a reduction in breast cancer risk in Asia. Other investigated risk factors included hormone therapy , radiotherapy , BC-associated depression and anxiety , environmental factors, including dichlorodiphenyltrichloroethane (DDT) exposure , and ratio of second to fourth finger length . Non-modifiable risk factorsThe key risk factors for BC are non-modifiable, the strongest of which is being female . Similarly to the studies in Western population , advancing age has also been identified as a non-modifiable risk factor for developing BC in participants from Asia . The studies identified two periods in which an increased BC risk emerged; first period at approximately 40–60 years, and a second peak at 85 years and over , which may be an important consideration for health service planning. BRCA1 and BRCA2 genes . Although the lifetime risk of BC among those with BRCA1 mutations can be as high as 80%, individuals with mutations in BRCA1 or BRCA2 generally have a 55–65% or 45% increased risk of BC, respectively . In 2016, the Asian BRCA consortium released its first paper on the management of hereditary breast and ovarian cancer (HBOC) in 14 Asian nations. This paper highlighted the disparity in the management of HBOC screening  between nations and recommended that policy makers, healthcare sectors and researchers address the limitations in HBOC testing and management . Results of the studies included in this review which considered the role of BRCA mutation in BC risk indicated that women with BC and a BRCA1 mutation had an earlier age of disease onset, higher nuclear grade of BC, and a younger age of hospitalization  when compared to those without the BRCA mutation. Other gene mutations can also lead to BC, for example, CHEK2, PTEN, CGH1, STK11 and PALB2 . However, they are generally viewed as being much less common and most do not increase the risk of BC to the degree seen with the BRCA genes; other non-BRCA mutations have also been linked to increased BC. Interestingly, certain gene variations were associated with decreased BC risk  , or both increased and decreased risk, depending on the gene variation investigated  .Approximately 5–10% of BC cases are thought to arise from gene mutations; the most common cause of hereditary BC is an inherited mutation in the Many women with BC do not have a family history of the disease. However, having a first-degree relative with BC is associated with a two-fold increase in risk of BC, and having two first-degree relatives can increase the risk three-fold . Accordingly, we found that family history of BC was associated with an increased risk in studies conducted among participants from China , Pakistan , Hong Kong , India , and Korea . Compared with other races or ethnic origins, Asian, Hispanic and Native American women may have a decreased risk of developing BC . This was supported by two studies which identified a reduced risk of BC among women from Asia and Malaysia compared with populations of women in the US . Early menarche (before age 12 years) and late menopause (after age 55 years) are associated with increased risk of BC, likely due to a longer lifetime exposure to estrogen and progesterone . Several studies demonstrated a link between menopausal status and BC risk and was seen across participants from Thailand , India , Pakistan , and Korea . As expected, the studies showed an increased BC risk in women who had a lower age of menarche  and a later age of menopause . An increased risk of BC was identified in participants with pre-existing medical conditions including multiple sclerosis and polycystic ovary syndrome .Modifiable risk factorsBeing overweight or obese is associated with an increased risk of BC, especially in women who have reached menopause. This is due to body fat, rather than the ovaries, becoming the primary source of estrogen in menopause . Internationally, several epidemiological studies have found that postmenopausal women with an increased BMI are at an increased BC risk of between 10–60% . In addition, being overweight or obese can increase insulin levels, and higher insulin levels have also been associated with increased risk of BC . Several of the studies in this review showed a correlation between increased BC risk and a high BMI, being overweight or obese, and low level of physical activity . In addition one study showed that underweight BMI at a young age (at ages 10 and 20 years) were associated with a decreased risk of BC . In parallel with these observations, physical activity  was associated with decreased risk of BC , although the exact amount of exercise needed to induce a protective effect remains unclear . The connection between BC, diabetes and obesity, was considered in a number of the identified studies. Breast cancer mortality risk was increased in women who had used insulin for more than 3 years ; additionally BC risk was associated with the presence of diabetes . when compared to non-tamoxifen users . Hypertension was observed in a higher proportion of BC patients with type 2 diabetes when compared to non-diabetic participants with BC .Women who have not had children or who had their first child after age 30 may have a slightly higher BC risk, whereas having many pregnancies and becoming pregnant at an early age may reduce the risk of BC . This was supported by some of the identified studies, in which BC risk increased when first full-term pregnancy was at an age greater than 25 years. Some studies also found that a later age at first live birth, first pregnancy and last pregnancy/birth also increased BC risk . BC risk was found to decrease in women with history of full-term pregnancy . However, one study noted that increased parity and early age at first birth were associated with increased risk of BC recurrence .Diet and the use of vitamins are modifiable risk factors with an unclear effect on BC. High consumption of fruits and vegetables was associated with decreased BC risk , and high intake of fatty foods was associated with increased BC risk . Data suggested that an intake of vitamin D, dietary fiber and intake of plant- and soy-based products may be protective for BC , whereas high intake of dietary salt, sugar and meat may increase the risk of BC .There is increasing evidence which supports the link between BC risk and heavy smoking over a long period of time . This was confirmed in several articles demonstrating a clear association between BC risk and exposure, either active or passive, to tobacco smoke . There are several limitations to this study. Firstly, due to the large number of articles identified, the results included are based only on the content of article abstracts, as assessed by a single reviewer. Therefore, the results analysis is limited due to some missing data on comparators, effect sizes and other statistical analyses. The missing data also make it difficult to prioritize results according to the strength or quality of included studies and/or data. The strength of the article may also be limited due to the absence of methods to assess risk of bias within individual studies and across studies, and the absence of additional analyses of the extracted data.In conclusions, this literature review has underscored the importance and relevance of known non-modifiable and modifiable risk factors for Asian women with BC. Furthermore, it has highlighted the differences in epidemiology of BC in Asian nations when compared to other regions. Only a few studies directly compared BC risk between Asian and non-Asian populations; in the ones that did, there was a decreased risk of BC among women from Asia compared with women from other countries such as the US.


This meta-analytic review aimed to examine the pooled prevalence rates of Internet addiction and gaming disorders in Southeast Asia. Several databases including PubMed, MEDLINE, PsycINFO, Web of Science, Embase, and Cochrane Central were searched and a total of 24 studies were included in this study. The selection of studies was conducted in accordance to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Two meta-analyses were conducted to examine data on Internet addiction and gaming disorders separately. A random-effects model was employed to derive the pooled prevalence rate. Mixed-effects meta-regression and subgroup analyses were performed to examine the moderators of the between-study heterogeneity. Publication bias was tested using the Egger’s regression test and funnel plot. Only seven out of the 11 Southeast Asian countries were represented in the literature. All except for two of the included studies were cross-sectional in nature. The findings revealed a pooled prevalence rate of 20.0%  and 10.1%  for Internet addiction and gaming disorders respectively. Mean age and study population were significant moderators of the between-study heterogeneity in the prevalence rates of gaming disorders such that samples involving older participants showed higher prevalence rate than those involving younger individuals. Country of study was found to be significant moderator of the between-heterogeneity for both Internet addiction and gaming disorders, however the findings should be interpreted with caution due to the small and unbalanced sample sizes. There was no significant publication bias. Such epidemiology research should be extended to the Southeast Asian countries that have not been studied or are under-studied. Given that the prevalence rates appear to be higher in Southeast Asia than in other world regions, future research should also explore the factors behind these inter-regional differences. Further longitudinal studies should also be conducted to examine the trajectories of such disorders. Over the past few decades, technological breakthroughs have fundamentally shaped the role of the Internet in our lives. The Internet has now become an integral part of our daily living across school, work, and leisure. In Southeast Asia, the Internet Penetration Rate (IPR), defined as the percentage of the total population who use the Internet, was the highest for Brunei as of June 2019 (94.9%), followed by Singapore (84.5%) and Thailand (82.2%) [This widespread use of the Internet has resulted in significant concerns with regards to problematic Internet behaviors and related conditions. Based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) diagnostic criteria on Pathological Gambling, Young  has defiWhilst there have been developments in the refinement of the diagnostic criteria for these disorders, there has since been more research done in this area. Notably, there has been a proliferation of epidemiological studies done to establish the prevalence rates of Internet and gaming disorders globally ,6. GivenTo the authors’ best of knowledge, there has only been one such study, Balhara and colleagues , that haIn order to address this research gap, this current study aimed to examine the pooled prevalence rates of Internet addiction and gaming disorders in Southeast Asia through a meta-analytic review of the available epidemiological studies conducted in the region. Meta-analysis is a quantitative approach to literature synthesis through the use of statistics and significance testing ,9. As coIn order to identify the relevant articles, the following databases were searched from inception till 26th January 2020, that of PubMed, MEDLINE, PsycINFO, Web of Science, Embase, and Cochrane Central. The following search terminologies were used for MEDLINE, that of “epidemiology” or “prevalence” and “Internet” or “gaming” or “digital gaming” and “addict” or “disorder” or “problematic” or “pathological” or “excessive” or “dependence” or “addictive behaviour”. As the interest was on articles from Southeast Asian countries, the following additional search terminologies were applied, that of “Thai” or “Singapore” or “Malaysia” or “Indonesia” or “Brunei” or “Myanmar” or “Vietnam” or “Cambodia” or “Lao” or “Filipino” or “Philippines” or “Southeast Asia”. This MEDLINE search strategy was adapted for the rest of the databases. The search strategy for each of the databases have been included as a Studies were included if they were: (1) original research, (2) examined prevalence rates of Internet or gaming disorders, (3) conducted in the Southeast Asia region, (4) conducted in general populations, and (5) the abstract was available in English language. Studies were excluded if they were: (1) non-original research (such as review studies), (2) did not report prevalence rates of Internet or gaming disorders, (3) not conducted within the Southeast Asia region, (4) conducted with psychiatric populations, or (5) the abstract was not available in English language.As meta-analysis is considered to be a form of secondary research involving the extraction of findings from prior studies, therefore ethical approval was not required for the current study.The selection of studies was conducted in accordance to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The title and abstract of the studies identified from the databases using the aforementioned search strategy were first screened for relevancy to the study topic on Internet and gaming disorders by two independent authors. The full-text article of the remaining studies were then assessed against the inclusion and exclusion criteria to determine the final pool of studies to be included in the current meta-analysis.Data from the included studies on Internet addiction and gaming disorders were extracted separately into two standardized spreadsheets by author DC. The following data were extracted: (1) citation including last name of first author and year of publication, (2) country in which the study was conducted, (3) study design, (4) study population, (5) sample size, (6) characteristics of sample including gender breakdown and mean age, (7) assessment tool utilized, and (8) prevalence rate. To ensure data accuracy, the extracted data were cross-checked by a second author (MZ). Any disagreements were resolved by means of a discussion between the authors DC and MZ. If they were still not able to resolve the disagreements, a third author was consulted.All statistical analyses were conducted using the Comprehensive Meta-Analysis Version 2.0 Program. The extracted data on Internet addiction and gaming disorders were analyzed separately via two independent meta-analyses. For the purpose of meta-analysis, the extracted data were coded into formats that were compatible with the program, e.g., categorical variables in text format were coded into numerical categories and percentages were represented in decimal format.For each of the two conditions, a random-effects model was employed to derive the pooled estimate of the prevalence rates, based on 95% confidence interval. This type of model assumes that the included studies are a subset of all possible relevant studies, accounting for true heterogeneity in effect sizes across studies on top of systematic sampling error, allowing for the generalization of findings beyond the context of the included studies ,13. A fo2 statistic, with null hypothesis assuming homogeneity. Based on the heuristic recommended in Higgins et al. [2 of 25%, 50%, and 75% reflect low, moderate, and high levels of heterogeneity respectively.Heterogeneity across studies was assessed through significance testing of the Is et al. , an I2 oZ and p values were reported. For categorical moderators, including country and study population, sub-group analyses using a mixed-effects model were done.Following the significant between-studies heterogeneity found, mixed-effects meta-regression analyses using unrestricted maximum likelihood estimation were conducted to ascertain if the continuous moderators, including mean age and proportion of male participants, were significantly associated with the between-study heterogeneity in prevalence rates. For meta-regression, the regression coefficients and the corresponding p < 0.05 signifying the presence of a significant publication bias. If a significant publication bias was shown, a Classic Fail-Safe test would be conducted to ascertain the number of omitted studies needed to counter the publication bias.A funnel plot was generated to assess publication bias, with asymmetry suggesting possible presence of publication bias. Egger’s regression test was also conducted to examine the significance of publication bias, with An initial pool of 184 citations were identified from the databases based on the search strategy. A total of 27 articles were found to be duplicates and were excluded. The screening of study titles and abstracts for relevancy to study topic resulted in the exclusion of 110 citations. Another 23 studies were subsequently excluded after the assessment of full-text article against the inclusion and exclusion criteria: did not report prevalence data on Internet addiction or gaming disorders (12 studies), non-original study (one study), use of psychiatric sample (one study), no access to full-text article (six studies), and sharing of duplicated dataset with an included study (three studies). A final count of 24 studies were included for the current study refer to . The afoOf the included studies, eight studies were conducted in Malaysia, six in Singapore, five in Thailand, three in Vietnam, one study examined data from Malaysia and Philippines, and the remaining study looked at data from Indonesia, Malaysia, Myanmar, Thailand, and Vietnam. In terms of the condition studied, 16 studies were conducted on Internet addiction, six studies on Internet gaming disorder or gaming disorders, and two studies looked at both Internet addiction and gaming disorders. The study populations included adults (12 studies), adolescents (six studies), children (one study), children and adolescents (two studies), and adolescents and adults (three studies). All except for two studies were cross-sectional in nature.For studies that examined more than one condition or country, the data on each condition or country were considered as unique data points for analysis. The characteristics of the included studies on Internet addiction and gaming disorders, including study details, country, study design, population type, sample size, mean age, gender breakdown, assessment tool, and prevalence rates, can be found in Z = −6.955, df = 22, τ2 = 0.883, I2 = 98.745). The forest plot shown in From the meta-analysis based on a random-effects model, the pooled prevalence rate of Internet addiction was found to be 20.0%  and proportion of male participants  were not significant moderators of the between-study heterogeneity. The meta-regression findings are summarized in There was significant between-study heterogeneity, s et al. , the I2 t = 0.968, df = 21, p = 0.344).There was no significant publication bias as indicated by the non-significant Egger’ regression test . The forest plot of prevalence rates of gaming disorders is illustrated in The pooled prevalence rate of gaming disorders based on a random-effects model was found to be 10.1%  was a significant moderator of the between-study heterogeneity, while proportion of male participants was not significant . The meta-regression findings are shown in Z = −34.074, p = 0.000) and study population  were significant categorical moderators. The findings on subgroup analyses are detailed in There was significant between-study heterogeneity, s et al. , the I2 t = 0.393, df = 6, p = 0.708).There was no significant publication bias as indicated by the non-significant Egger’ regression test , with the first being Northern Europe (95.0%), followed by Western Europe (92.0%), and Northern America (88.0%) . DespiteI2 of 98.7% and 97.4%, the current meta-analysis revealed high levels of between-study heterogeneity in the prevalence rates of Internet addiction and gaming disorders. The subsequent meta-regression and subgroup analyses explored mean age, proportion of male participants, country, and study population as potential moderators that may have contributed to the heterogeneity. In particular, mean age was found to be a significant moderator for gaming disorders, such that higher mean age of sample was associated with higher prevalence rate. Older individuals, such as college students and working adults, often have more autonomy and opportunities to utilize smart devices. This, coupled with their technological proficiency and the lack of external supervision, may put them at higher risk for gaming disorders. On the other hand, parents of younger children or adolescents, particularly in the Asian culture, may impose supervision and restrictions on their children’s involvement in gaming behaviors due to academic concerns, reducing their risk for pathological gaming [n = 16; n = 2), adolescents , children , adolescents and adults , and children and adolescents ). For both conditions, country of study was shown to be a significant moderator. Likewise, this finding should be interpreted with caution as not all Southeast Asian countries were represented, and for the represented countries, there was only limited and unbalanced number of studies. For instance, only seven out of the 11 Southeast Asian countries were represented in the epidemiological literature for Internet addiction , Vietnam (n = 4), Singapore (n = 3), Thailand (n = 3), Indonesia (n = 1), Myanmar (n = 1), and Philippines (n = 1)). Similarly, only two countries were represented for gaming disorders (Singapore (n = 5) and Thailand (n = 3)).As indicated by the significant tests of heterogeneity and l gaming ,45. Besil gaming , adolescl gaming ,48. In tl gaming  found thGiven the high levels of heterogeneity, there may be other moderators that were not explored in the current study due to the lack of data. For instance, the heterogeneity may be accounted for by the diversity in the assessment tools employed by the included studies i.e., varied assessment tools and varied cut-off criterions. A total of 10 different assessment tools were employed across the 23 studies on Internet addiction and five were used across the eight studies on gaming disorders. The varied assessment tools were observed to produce differing prevalence rates. Using the Internet Addiction Test (IAT) and the Revised Chen Internet Addiction Scale (CIAS-R), Mak et al.  examinedAs with all studies, the current study has its own limitations. Firstly, despite having the aim of synthesizing the epidemiological studies on Internet and gaming disorders in Southeast Asia, not all Southeast Asian countries were represented due to the availability of literature. Moreover, the number of studies for each country was limited. The lack of studies may affect the generalizability of findings to Southeast Asia as a whole. Next, given the high levels of between-study heterogeneity, there may be other potential moderators that were not examined. As mentioned above, the assessment tools utilized in the included studies were diversified in terms of differing scales and cut-off criterions. However, these potential moderators were left unexplored as subgroup and meta-regression analyses were not feasible due to the limited number of studies. Additionally, the subgroup analyses on the moderating effects of population type and country on the between-study heterogeneity should be considered to be exploratory due to the small and unbalanced sample sizes of studies to represent each level of the moderators. In addition, the prevalence rate in one study, Ng et al. , did notDespite the limitations, the current study is one of first efforts to synthesize the epidemiological literature on Internet and gaming disorders in the Southeast Asia context. Compared to traditional qualitative reviews, the study conducted meta-analysis which is a more robust and objective method to literature synthesis. By using meta-analysis, the study was able to derive pooled estimates as proxies of the prevalence of Internet and gaming disorders in Southeast Asia. Moreover, the study has also explored potential moderators that may influence the prevalence rates.Through the current findings, several future research directions have been identified. To the best of the authors’ knowledge, the epidemiology of Internet and gaming disorders have not been examined in some Southeast Asia countries including Brunei, Cambodia, Timor-Leste, and Laos. For those countries that have been covered, most were underrepresented. Accordingly, more research work can be done in the Southeast Asia countries to better understand such disorders in the region. Next, the study has revealed higher prevalence rates in Southeast Asia as compared to other world regions. Future studies should seek to explore the contributing factors and nuances behind these inter-regional differences. Lastly, all except for two of the included studies were cross-sectional in nature, future research may seek to conduct more longitudinal studies to examine the trajectories of Internet and gaming disorders.There are several clinical implications that arise from the current findings. The prevalence of these disorders implies there being a need to screen for these disorders proactively amongst individuals who are coming forth for treatment. Screening should also be done amongst individuals with other psychiatric disorders, such as attention deficit hyperactivity disorder, social anxiety disorder, depressive disorder and alcohol abuse, as prior studies have reported there being an association between Internet Addiction, gaming disorders and these other psychiatric comorbidities ,50.In conclusion, the current meta-analysis found the pooled prevalence rates of Internet addiction and gaming disorders in Southeast Asia to be 20.0% and 10.1% respectively. The meta-regression and subgroup analyses showed that mean age and study population were significant moderators of the between-study heterogeneity in prevalence rates of gaming disorders with older samples showing higher prevalence rates than younger samples. Even though country of study was found to be a significant moderator for both Internet addiction and gaming disorders, findings should be interpreted with caution due to the small and unbalanced sample sizes. Future studies should extend such epidemiological research to Southeast Asian countries that have not been studied or under-studied. Given that the prevalence rates of Internet addiction and gaming disorders in Southeast Asia appear to be higher than that in other world regions, future research should examine the factors behind these inter-regional differences. Further longitudinal studies should also be conducted to examine the trajectories of such disorders.


Zostera marina L.) is the dominant seagrass species in the temperate northern hemisphere, but its global distribution has reduced dramatically. The main aims of this study were to determine: (1) the depth limit for Z. marina survival in Ailian Bay, north China, and (2) how light availability affects the growth and recruitment of Z. marina as a basis for identifying a suitable depth range for successful restoration. To achieve these aims, Z. marina shoots were transplanted from a nearby donor site, Swan Lake, to an experimental site, Ailian Bay, and the temporal responses of Z. marina shoots to light availability at water depths ranging from 1 to 8 m were investigated using in situ suspended cultures. Four suspended shoot transplantation experiments were conducted in 4 years. The results showed that the transplanted Z. marina shoots could survive and branch during an annual growth cycle, permanently underwater, at a depth ≤3 m. Due to the local turbidity of the waters in Ailian Bay, a depth of 4 m led to sufficient light deprivation (reduced to 6.48–10.08% of surface irradiance) to negatively affect seagrass shoot density and clonal reproduction. In addition, reproductive shoot density also tended to decline with water depth and light deprivation. Our results indicated that Z. marina population recruitment, through sexual and asexual  reproduction, were negatively affected by increasing water depth and light deprivation. These findings may provide a suitable depth range for the successful restoration of Z. marina in local coastal waters. They may also be applied to the management and restoration of Z. marina globally.Accelerating losses of seagrass meadows has led to efforts to restore these highly productive and beneficial ecosystems globally. Depth and light availability are critical determinants of seagrass restoration success. Eelgrass ( Seagrass meadows are among the most productive plant communities, providing habitats, food, and nurseries for a variety of marine organisms , regulatZostera marina L. is the dominant seagrass species throughout the Atlantic and Pacific coasts of the temperate northern hemisphere  the depth limit for the survival of eelgrass (Z. marina) in Ailian Bay, and (2) how light availability affects the growth and recruitment of Z. marina as a basis for identifying a suitable depth range for successful restoration. The results from this study could provide important implications for future management and restoration of eelgrass, to avert further loss and enhance the potential for recovery. Additionally, in situ suspended seagrass cultures are described that may serve as a useful methodology for future field simulation experimentation.In the present study, an 2 marine lagoon that is connected to Rongcheng Bay by a narrow mouth, 86 m in width. The lagoon, a national nature reserve for the whooper swan, Cygnus cygnus, provides food resources and the largest wintering habitat for this bird in Asia , pH, chlorophyll content (μg L–1), and depth (m) were measured using a multi-parameter water quality sonde . The parameters were measured over a 2–15 min period at each depth. The measuring sonde was moved up and down the water column while several measurements were recorded at various depths , all within an hour. Variations in water parameters with depth were measured five times in total during April, May, June, August, and November 2014.Water temperature (°C), salinity (ppt), dissolved oxygen content  was measured using an ECO-PARSB sensor . The light sensor was moved up and down the water column with light availability measurements recorded at various depths , all within an hour. Light intensity was obtained at four different days/times in total, in May, August, and October 2014, and the light intensity was measured every minute.Light availability  is shoot density, z is depth at each time point of each year, and a and b represent equation coefficients. Here, S(z) is the vegetative shoot density, not the total shoot density, because vegetative shoot density is more suitable for the evaluation of lateral shoot branching, and reproductive shoots disappear in August every year. Any depths at which the measured shoot density overlapped with zero were excluded from linear model fitting. All linear regressions were performed using R version 3.6.3.Such analyses were not performed for reproductive density or shoot height because quantitative relationships, such as those expressed in equation (1), could not be identified from a visual inspection of the data.To explore whether water clarity varied spatially, and thus determine if the depth limits obtained from the analysis were affected by any spatial variations in water clarity, the spatial correlation of water turbidity with depth was assessed see . This waI represents the light availability at water depth z (m), I0 represents the surface light, and d∗K represents the light attenuation coefficient (m–1), which was not corrected for the sun’s location in the sky.where, Some PE boxes were overturned by marine currents during 2010–2011; therefore the design parameters of the experimental device were altered. In order to reduce the impact of currents on the experimental device, improvements to the stability of the device in seawater were attempted by reducing the drag force. The drag force is related to fluid density, frontal area of object, drag coefficient, and the velocity of fluid, and the shape of an object has a large effect on the amount of drag . This caFd is the drag force, ρ is the mass density of the fluid, μ is the flow speed of the object relative to the fluid, Cd is the drag coefficient, and A is the frontal area.where, In order to change the shape (reducing drag coefficient) and reduce the frontal area of the experimental device, PVC pots were alternatively used in 2014. The drag coefficient ranges of the PE box (cuboid) and PVC pot (short cylinder) were 1.05–2.05  and <0.6Z. marina remaining at 6 m and 8 m after approximately half a year of experimentation , and approximately three-fold greater than those at 3 m. Very few shoots at 4 m depth survived until the end of the experiment, and shoots at 6 m depth had completely disappeared within 4 months. The temporal and spatial trends of vegetative shoots densities were consistent with those of the total shoots . Light intensity changed significantly as depth increased, and all four of the light vs. depth distributions adhered well to Beer’s Law  changes with water depth were mostly slight. Temperature changes with water depth were relatively high in the warm season , ranging from 0.28 to 0.75°C/m . The regZostera marina is a major habitat-forming species in north China. Its distribution may be threatened by changes in water clarity through increased sedimentation and nutrient input from agricultural and urban development (Z. marina) and provided a suitable depth range for successful restoration in local coastal waters, north China. More broadly, this study assessed the effect of light availability on the growth and recruitment of Z. marina conducted by in situ transplanted suspended cultures.elopment . The prein situ investigations or laboratory experiments. Laboratory experimental systems remove important contextual factors under natural conditions   , and the growth) . For fie growth) .in situ suspended culture experiment was developed in this study to directly examine long-term responses of transplanted Z. marina shoots to a depth gradient, in order to determine the depth limit for eelgrass restoration. Moreover, in situ suspended cultures may prove to be a useful method for seagrass research, e.g., studying the effect of habitat type on eelgrass seed germination (unpublished data). Over the 4 years of in situ suspended experiments, the stability of the experimental device was improved by switching from PE boxes to PVC pots, based on device drag force comparisons. The drag force of the PE box was approximately double to six-fold that of the PVC pot; indicating a greater stability of the PVC pot, and consequently none of these were overturned by marine current. In addition, because it is much easier for the PE box to rotate around its vertical axis under the influence of current, the PVC pot appears to be a more stable device for suspended cultures of eelgrass. For marine areas with strong currents, a heavier plumb ball can be added at the bottom of the experimental device to improve the stability of the system.To overcome inherent weaknesses of the abovementioned experiments, an Z. marina depth limit determined for Ailian Bay in this study was higher than that of the distribution depth , appeared to show a downtrend. Z. marina at 4 m depth might disappear over a longer time scale with 1.75–2.88% of surface irradiance, since these values are lower than the minimum light requirement of 4–36% of surface irradiance for seagrass reported previously   . Regardi–1) .R2 ≥ 0.82), indicating that the variation in turbidity with water depth was not substantial. Since long-term measurements of subsurface photosynthetically active radiation were not recorded for the duration of the experiment, it is difficult to convert the estimated depth threshold of 3 m to a similarly precise light threshold for Z. marina. However, combining all estimated values of d∗K shown in As shown in In situ reductions of light are known to affect seagrasses in a variety of ways. Several studies have shown stunted growth, reduced biomass, and lower densities in response to reduced light  to directly examine long-term responses of transplanted Z. marina shoots to a depth gradient, in order to determine the depth limit (light requirement) for eelgrass restoration. The findings indicate that adult Z. marina transplants originating from a nearby matching donor site (Swan Lake) can successfully acclimatize and be used for restoration within degraded areas (Ailian Bay) requiring eelgrass restoration. These results provide a suitable depth range for successful restoration of eelgrass in Ailian Bay, north China. More broadly, this work may provide useful knowledge for the global management and restoration of seagrass.This study presented a novel method (The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.SX: writing – original draft, conceptualization, methodology, investigation, and validation. PW, FW, PL, and BL: investigation, formal analysis, and writing – review and editing. XZ: data curation, formal analysis, investigation, and writing – review and editing. SY and YuZ: investigation and data curation. YiZ: funding acquisition, supervision, methodology, investigation, and writing – review and editing. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


In addition, there were also significant differences in the heel pronation angle (p = 0.005) and variability and energy consumption of the angles in the anterior–posterior axis , medial–lateral axis , and vertical axis . Our study demonstrated that a single IMU on the posterior heel of the dominant side can address the variability of kinematics parameters for elderly performing prolonged brisk walking and could serve as an indicator for walking instability, and thus fatigue. Real-time detection of fatigue in the elderly during physical exercises can help identify the stability and thus falling risks which are commonly achieved by the investigation of kinematic parameters. In this study, we aimed to identify the change in gait variability parameters from inertial measurement units (IMU) during a course of 60 min brisk walking which could lay the foundation for the development of fatigue-detecting wearable sensors. Eighteen elderly people were invited to participate in the brisk walking trials for 60 min with a single IMU attached to the posterior heel region of the dominant side. Nine sets of signals, including the accelerations, angular velocities, and rotation angles of the heel in three anatomical axes, were measured and extracted at the three walking times  of the trial for analysis. Sixteen of eighteen participants reported fatigue after walking, and there were significant differences in the median acceleration ( Physical exercise is imperative for the elderly to maintain and promote a healthy lifestyle . At leasPrevious studies have found some indicators related to walking fatigue for the elderly. Fatigue attenuated the range of motion and muscle strength of the ankle joint of the dominant leg , in addiThe application of an inertial measurement unit (IMU) is becoming popular recently due to its superiority in portability, cost, and accessibility compared to traditional gait labs with motion capture systems and force platforms . IMUs weWhile there is an abundance of research on the walking fatigue of the elderly, the measurement (including the baseline and fatigue state) was often standalone from the fatigue-inducing task . This mIn this light, we propose to collect the kinematic data throughout the whole fatigue-inducing tasks for analysis without a standalone testing trial for measurement. This approach could ensure that the participants will not recover halfway, and the fatigue-inducing effect could be continuous. In addition, the advantage of this study lies in its potential to predict instability or fatigue using a single sensor measuring the orientation, angular velocity, and linear acceleration of the posterior heel. The main purpose of this study is to study the influence of fatigue induced by brisk walking on gait parameters by using an IMU and identify fatigue indicators. It is hypothesized that lower-limb muscle fatigue will manifest the deterioration of stability and increase energy consumption. This study is not only helpful for the elderly’s fast walking exercise but also the development of wearable fatigue recognition equipment, the elderly’s fall prevention, and rehabilitation training.This paper includes five parts. The Introduction section covers the research background and significance of fatigue indicators. The Materials and Methods section provides the information of participants, experimental protocol, outcome measures, and statistical analysis. The Results section highlights the changes in outcome measures across the time of long-term brisk walking as well as the results of the statistical analysis. Subsequently, we address the implications of our key findings and the limitations of our study in the Discussion section. Lastly, we conclude the feasibility of our system on fatigue detection with a cautious note on the relationship between the variability of kinematics and fatigue.Eighteen older adults, nine males and nine females, were recruited from the university campus by posters and leaflets. The average age, height, and weight of the participants were 60.4 ± 7.9 years, 161.0 ± 7.6 cm, and 62.7 ± 11.7 kg, respectively. All these participants were independent walkers with a heel strike walking style. The exclusion criteria included persistent knee pain, osteoarthritis, unstable ankle, severe flat foot, severe hallux valgus, toe deformities, and other chronic diseases that might lead to safety issues. The participants shall also have no history of injuries in the past six months. All participants signed the informed consent, and this study was approved by the Human Subjects Ethics Sub-committee of The Hong Kong Polytechnic University (Reference Number: HSEARS20190919001).All participants wore the same type of cushioned running shoes, ARHQ025-4 , with self-selected sizes, from 36 to 43 (European size). The insole, upper, and outsole are made of Ethylene-vinyl acetate copolymer (EVA), synthetic, and rubber, respectively.The closure type is lace-up. Before the running task, the safety precautions in using the treadmill  and the general procedures of the experiment were explained to the participants. By increasing the treadmill speed by 0.5 km/h every 30 s , particiThe acceleration, angular velocity, and angles of the posterior heel region of the dominant foot in the anterior–posterior axis, medial–lateral axis, and vertical axis were measured using a single IMU . The hardware of the IMU utilized an MPU 9250 . The software of the IMU integrated dynamics calculation and the Kalman filter algorithm and provided a mobile application that can collect data in real time. The IMU was attached on the middle posterior heel of the dominant foot as shown in The average baseline orientation of the IMU was measured when the participants walked for the first 30 s of the walking trial. The calculated angles referred to the changes in orientation angle compared to the average baseline orientation.We extracted the baseline (1st-min), 30th-min, and 60th-min data for analysis. The outcome measures included the acceleration, angular velocity, and angle in the anterior–posterior axis, medial–lateral axis, and vertical axis. Ten parameters were derived from these three time series’ primary data including the median absolute deviation (MAD), kurtosis, skewness, root mean square (RMS), variance, maximum absolute value, minimum absolute value, amplitude range, the median of absolute value, and the average of energy consumption (EC). In this study, signal power was regarded as EC, and the signal power of a real-valued signal  follows :(1)P=limThe process of data processing is summarized as follows.Extract the data of the baseline min, 30th min, and 60th min, and incomplete gait cycles are ignored.Calculate these 10 parameters of each gait cycle in these three time periods, then calculate the average value for each parameter.Normalize by dividing each participant’s baseline-min, 30th-min, and 60th-min data by their respective baseline-min data to get the proportion of change of each parameter relative to the baseline, thereby eliminating the difference in gait parameters between the experiments. The units of each parameter are 1 since each parameter uses a ratio.Take the RMS of the 30th min as an example. The baseline min, the 30th min, and the 60th min consist of Statistical analysis was used to determine whether there were statistically significant differences in the outcome measures (detailed in p > 0.5). Therefore, the nonparametric test (Friedman test) was used. The significance level (α) was set at p = 0.05. If the findings of the Friedman test were statistically significant, a post hoc pairwise comparison, the Wilcoxon signed-rank test, was conducted with Bonferroni correction at p < 0.017.The data were not normally distributed as assessed by the Shapiro–Wilk test  and median (p < 0.002) of the x-axis acceleration, the RMS (p < 0.03), variance (p < 0.03), minimum (p < 0.002), and EC (p < 0.03) of the y-axis acceleration, and the skewness (p < 0.03) and median (p < 0.03) of the z-axis acceleration.There were eight significant differences in statistical features in the three axes’ accelerations, as shown in The post hoc pairwise comparison test  revealedp < 0.03), maximum (p < 0.03), and EC (p < 0.02) of the x-axis angular velocity, while there was no significant difference in the y-axis and z-axis angular velocities. The post hoc pairwise comparison test (As son test  proved tp < 0.03), maximum (p < 0.002), range (p < 0.002), and EC (p < 0.03) of the x-axis angular; the RMS (p < 0.02) and EC (p < 0.02) of the y-axis angular; and in the kurtosis (p < 0.02), skewness (p < 0.05), RMS (p < 0.003), maximum (p < 0.03), minimum (p < 0.006), range (p < 0. 006), median (p < 0. 006), and EC (p < 0.001) of the z-axis angular, as shown in There were significant differences in the RMS  responded that their subjective fatigue felt significantly increased, which imposed an apparent effect on the kinematic parameters of the individuals’ posterior heel of the dominant foot. After long-distance brisk walking, the participants showed a significant increase in (1) the median of acceleration in the medial–lateral axis (The increment in the medial–lateral acceleration indicates greater vibration of the dominant lower limb in the medial–lateral axis. This signal was likely manifested by a muscle fatigue condition since the acceleration signal reflects the mechanical activity of the muscle , which wThe maximum angular velocity in the medial–lateral axis tended to increase after long brisk walking, and we assumed that this is a strategy to shorten the time of dominant foot swing and increases the double support time. This assumption was consistent with one previous study that suggested, in order to adjust the microbalance before the swing phase of the dominant limb becomes more unstable after fatigue, a longer double support time and shorter support time are required . The incAfter prolonged brisk walking, the maximum rotation angle in the medial–lateral axis became larger and could result in a larger rotation range. This phenomenon may represent a longer double support time, agreeing with the results of previous studies ,18,34,35Furthermore, both variation and energy consumption of rotation angles increased in the three axes of anterior–posterior, medial–lateral, and vertical directions after long-distance brisk walking. This result is similar to a previous study that found, when the muscles adjacent to the joint are fatigued, there could be a decrease in the synergy between the neuromuscular feedback of the joints and the proprioception of the joints ,18,38,39There were some limitations to this study. Due to the ethical considerations, elderly participants recruited in this study were generally more physically active and fit, to minimize the falling risks by this challenging prolonged brisk walking task. The physical fitness of the elderly people could be the confounding or effect modifier to the identifiers. In the real case, some elderly people could be reluctant to exercise and could be less physically tolerable. Sampling elderly people with different levels of physical fitness or risk of falls may improve the external validity of our findings, which could be conducted using postural stability tests ,42. On tWhile the IMU system in this research aims to simplify and minimize the number of IMUs for fatigue identification, it should be noted that a number of research works have endeavored to investigate the influence of fatigue on variability, stability, and gait asymmetry . IncorpoThis study utilized a single IMU to measure the linear acceleration, angular velocity, and rotation at the posterior heel during a 60-min brisk walking trial among elderly participants. The prolonged brisk walking induced a significant change in the signal parameters in the medial–lateral directions, including the linear acceleration, angular velocity, and heel rotation range. In addition, higher variability and energy consumption were also found on the angular velocity in the medial–lateral direction, as well as on the heel rotation angles in all directions.Our study demonstrates that the brisk walking trial induced fatigue in the elderly participants as demonstrated by the subjective feedback. It should be noted that fatigue is a complex symptom, being the result of the complex interaction of physiological systems and the brain . Since t