This study evaluates the contribution of schools in Saudi Arabia towards the provision of education and support concerning weight management among adolescents. It also identifies adolescents who have attempted to lose weight and examines their preferred weight-loss methods and their sources of weight-loss support. This study is a cross-sectional investigation that targets adolescents in intermediate and secondary schools in Jazan, Saudi Arabia. Data was collected via a self-administered questionnaire that looked at the involvement of the school in the provision of education pertaining to weight control and the weight-loss experiences of students who had attempted to lose weight. The study involved 501 adolescents, 45% of whom had attempted to lose weight, where the most common methods for weight loss being reducing food consumption (77%), exercising (75%), and fasting (49%). The assessment of the schools’ contributions indicated its suboptimal role in the provision of education concerning physical activity compared to education about eating habits. The most commonly reported sources of weight-loss support were the students’ families (54%), followed by community facilities (44%). The least common sources were the students’ schools (24%). These findings indicate that schools need to enhance their contribution to encouraging adolescents to adopt a healthy lifestyle, while also ensuring multi-sectorial collaboration with families and community members.  Overweight and obesity is a public health concern in Saudi Arabia. According to the Saudi Ministry of Health, nearly 60% of Saudi adults are overweight or obese . ChangesOverweight and obesity is a prevalent health issue among adolescents in the country. In a systematic review of studies published between 2002 and 2018, the assessed prevalence of overweight and obesity among adolescents in Saudi Arabia was between 22% and 48% and showed an upward trend over the last two decades . This inSeveral investigations have been conducted in Saudi Arabia to understand the determinants of overweight and obesity among Saudi adolescents and children. In a study that utilized a participatory approach to measure the perspectives of students, school staff, Ministry of Education officials, and parents regarding school-related factors associated with obesity in girls aged between 13 and 15 years, it was concluded that offering affordable healthy food items (fruits and vegetables) and removing unhealthy food items (sweets and chocolate) from the school canteen, as well as more education about healthy foods, were important elements for school-based interventions aiming to reduce obesity .In a study that involved a sample of 2696 students based in the south of Saudi Arabia and aged between 11 and 19 years, it was concluded that limited physical activity and exercise, either in general or during school activities, were associated with higher rates of obesity . In a siEarly recognition and management of overweight and obesity among children and adolescents are important for reducing the negative health impacts and morbidities associated with these conditions . SeveralThe Saudi Guidelines for the Prevention and Management of Obesity provide recommendations for obesity prevention in children that include eating habit guidelines and the promotion of physical activity. The former involve specific dietary recommendations that encourage children to eat until they are full, consume regular meals including breakfast, and have a low consumption of salty and energy-dense foods. They also recommend that children consume five portions of fruits and vegetables a day, eat in sociable settings, and do not have easy access to food that is not suitable for children.To promote physical activity in children and adolescents, the guidelines recommend reducing screentime to less than two hours a day and ensuring a minimum of one hour of active play. It is also suggested that the whole family should be involved in increasing the physical activity levels of children. If a child or adolescent is not able to maintain their body weight or prevent weight gain, referral to a specialist is advised, especially if there may be an eating disorder, poor body image, depression or anxiety, the presence of a comorbidity or underlying medical issue, or if there is a need for pharmacological or surgical intervention for weight management .The Saudi Guidelines for the Prevention and Management of Obesity also recommend developing sustainable school-based interventions for proper prevention of overweight and obesity among children and adolescents. These interventions should consider an inter-sectorial approach that includes their families. Unfortunately, there is limited information regarding the involvement of schools in Saudi Arabia in the provision of school-based interventions aimed at weight management in children and adolescents. In a recent study by Al-Daghri et al. , which wAlthough the current weight-management guidelines in Saudi Arabia recommend school-based interventions for tackling childhood obesity, the provision of such interventions is extremely limited. Furthermore, studies that assess the involvement of schools in Saudi Arabia in the promotion of healthy eating and physical activity are also limited. The contribution of schools in Saudi Arabia, via the established official educational program, towards the prevention of overweight and obesity among adolescents is currently unknown. Therefore, the current study measures the contribution of schools in the Jazan region, in the southwest of Saudi Arabia, towards the provision of education concerning the prevention of overweight and obesity among adolescents. It also identifies adolescents who have attempted to lose weight and examines their preferred weight-loss methods and their sources of weight-loss support.This investigation used a cross-sectional design to sample adolescents studying in intermediate and secondary schools in Jazan, Saudi Arabia. Data collection was initiated after securing ethical approval from the Standing Committee for Scientific Research of Jazan University . Data were collected via an online platform, and an online information sheet explaining the study was shared with parents. The parents who agreed that their children could take part in the study allowed their children to complete the online questionnaire.A self-administered questionnaire collected information about the participants’ demographics, their reported body weight and height, the involvement of their schools in the provision of educational materials related to weight control, their body weight satisfaction, and the experiences of participants who had tried to lose weight. The sections of the questionnaire that measured the participants’ perceptions of their weight, their methods of weight loss, and the involvement of their schools in providing education related to weight control, were adopted from the Global School-based Student Health Survey.The participants were asked about any education they had received concerning healthy eating, the benefits of consuming fruits and vegetables, methods for maintaining a healthy body weight, the risks of eating salty and energy-dense foods, sport in school, the benefits of physical activity, or the prevention of injury when taking part in sporting activities . The parThe questionnaire was converted to an online format using Google Forms and a weblink was generated to distribute the data information sheet and the questionnaire to the parents of the participants. The parents were recruited by advertising the study in WhatsApp groups, which are a popular method of communication in school and work settings in Saudi Arabia .The consenting parents were asked to give the questionnaire to their children to complete. They were also asked to share the weblink with their relatives and friends to help achieve the target sample size. Sample size estimation was conducted via the StatCal function of Epi Info. As no previous studies have used the Global School-based Student Health Survey to measure the contribution of schools towards weight management education among adolescents, it was estimated that 50% of the sample would have received relevant education. The target sample size was 480 participants, assuming a prevalence of 50% with a 5% margin of error, 95% confidence interval, and 25% refusal to participate. The expected frequency of 50% was selected for sample size estimation as it produced the maximum sample size according to the selected sample size parameters.Data analysis was performed using the IBM Statistical Package for the Social Sciences, version 24.0. Frequencies and proportions were used to summarize the binary and categorical data, while means, medians, standard deviations, and interquartile ranges were used to describe continuous data depending on their distribution. A standard Chi-square test investigated the relationship between BMI levels and the intention to lose weight across the sample.p-value of <0.05 was used to indicate statistical significance.BMI levels were calculated by entering the participants’ reported weight and height into the BMI Percentile Calculator for Child and Teen from the Centers for Disease Control and Prevention. The participants were then classified as underweight, normal-weight, or overweight/obese. The chi-square test looked at the relationship between the participants who had tried to lose weight in the previous three years and their BMI, body weight satisfaction, and education level. A The total number of participants who completed the questionnaire was 501. The majority of the sample were female (61%) with a mean age of 16 years (SD = 1.9). More than half of the participants lived in urban areas (54%), and the majority were secondary school students (67%). When asked about their family, 86.5% of participants indicated that they were living with both of their parents, and more than half (57%) indicated that they had up to four siblings. Over half (60%) of the sample had a normal body weight, while nearly one quarter (24%) were overweight or obese. The most frequently reported medical condition was asthma (6.2%), followed by dental illnesses (5.4%). Finally, half of the sample (51%) reported that one or both of their parents had a chronic disease. See Slightly fewer than half of the participants (45%) reported attempting to lose weight. p < 0.05). Interestingly, six participants (8%) classified as underweight and 121 (41.6%) classified as normal-weight had also tried to lose weight in the last three years. This suggests low body weight satisfaction among underweight and normal-weight participants. Finally, there was no significant difference between genders in relation to weight-loss attempts.This study investigated the provision of education related to the prevention of overweight and obesity in adolescents and the methods used by adolescents who had attempted to lose weight. The assessment of the schools’ contributions to educating their students about weight management indicated that they were less likely to provide education about the benefits of physical activity compared to education about healthy eating habits.Just under half of the participants reported being unsatisfied with their body weight, with a similar amount reporting that they believed they had a normal body weight. About 45% had attempted to lose weight during the previous three years, with the most common methods being reducing food consumption, fasting, and exercising. When asked about their sources of support when trying to lose weight, the most frequently reported source was their family, while the least reported source was their school. Interestingly, a number of students who were classified as underweight or normal-weight adolescents had tried to lose weight in the past three years, which suggests they had low body weight satisfaction.There is a limited number of studies looking at the influence of schools on the eating behaviors and physical activity levels in Saudi adolescents. In a study that assessed the eating habits of 1149 elementary school students from Jeddah, Saudi Arabia, it was found that 56% consumed food and beverages from the school canteen. However, no information regarding their choice of food and beverages or their body weight was provided . A similThe current study showed that some adolescents had attempted to lose weight despite having a normal body weight or even being underweight, suggesting that they had misperceptions about their body weight. This is similar to the findings of a study by AsSaigal et al. that measured the body weight perceptions of 270 male secondary school students in the Qassim region of Saudi Arabia. They found that 35% perceived their weight incorrectly, with 18.4% of overweight and obese students perceiving their weight as normal, 53% of the underweight students also perceiving their weight as normal, and 20% of the normal-weight students perceiving themselves as overweight .The attempts of adolescents who are normal-weight or underweight to lose weight can be explained by several notions related to human behavior. Adolescents, during school year and during their development, can be subjected to peer pressure and the associated body-weight shaming and stigmatization, making them more inclined to adopt harmful weight loss measures. Additionally, body weight misperception among adolescents can be influenced by the body weight norm in communities which favor individuals who are thin. Though not measured in the current study, recent evidence indicates that body image among adolescents is further affected by the impact of social media, motivating adolescents, especially girls, to weigh less and may eventually lead to the development of unhealthy eating behaviors and eating disorders . This idAttempts to lose weight among adolescents, as well as unhealthy dieting, has been explained by several different types of factors, such as body image dissatisfaction , the absence of positive adult role models , and a poor school involvement  . InteresThis study found that families are a more common source of support for weight loss compared to other institutions such as schools. This is similar to the results of other studies, which have shown that parental involvement can be a motivating factor for adolescents. In a study looking at 49 American adolescents who had attempted to lose weight, it was concluded that younger adolescents were more likely to be motivated to lose weight if their parents were involved compared to older adolescents . The curThe current study identified several different methods used by adolescents when trying to lose weight, with the most common being reducing food intake and exercising. This is similar to the findings of the American National Health and Nutrition Examination Survey, which indicated that exercising was the most frequently used method of weight loss among adolescents aged between 16 and 19 years . SimilarThe current study found that weight-loss attempts were more likely in secondary school adolescents compared to the younger, intermediary school adolescents, suggesting that age influences the likelihood of a student attempting to lose weight. Nonetheless, the study by Rancourt et al., which assessed success of weight loss initiation and maintenance among adolescents with overweight and obesity, indicated that adolescents at a younger age were more likely to initiate weight loss attempt when their parents were involved. Nonetheless, Rancourt et al. also reported that older adolescents were more likely to initiate weight loss on their own, even with less parental involvement . AlthougInterestingly, gender was not found to influence whether or not a student attempted to lose weight. These findings are similar to those of a large-scale European study by Dzielsa et al., which involved a sample of more than 600,000 adolescents from 26 European countries and compared weight-loss behavior in 2001/2002 to that in 2017/2018. They found that girls were more likely to engage in weight-loss behavior in 2001/2002, but that this gender difference reduced over time, with more boys attempting to lose weight during 2017/2018 . In contThe current findings indicate that nearly 58% of the recruited adolescents were satisfied with their body weight. Nonetheless, among those who reported being satisfied with their body weight, 63 adolescent students (22% of the those who are satisfied) declared their wish to alter their body weight. It is possible to argue that the identified 63 adolescents may exhibit lower satisfaction levels in comparison to the majority of the satisfied adolescents who did not wish to alter their body weight. However, this was not measured in the current study since satisfaction was assessed via binary answering options . Furthermore, satisfaction levels can be associated with different factors such as age, gender, BMI level, body composition, and appearance. This suggests the need for further research to assess satisfaction levels .Adolescents in Saudi Arabia spend a very significant part of their lives in schools. The education system and school environment are directly involved with the mental, emotional, and physical well-being of adolescents. It is possible to argue that any public health intervention targeting adolescents would not succeed without the optimal involvement of schools. Overweight and obesity during adolescence is rather critical due to its long-term impact and the raised risk of developing chronic non-communicable diseases during a later phase of life. Therefore, schools should invest in enhancing their communication with young people, especially during the developmental changes the adolescents are experiencing.Enhancement of the communication of schools with young people can be implemented on several levels. Firstly, in a country that is witnessing a rise in the incidence of lifestyle-influenced chronic diseases such as obesity, diabetes, and hypertension, education about healthy eating and physical activity should be a core part of the curricular activities delivered to the students. Secondly, schools should provide tailored extracurricular activities for adolescents who are suffering from raised BMIs or are at risk of developing obesity. These curricular and extracurricular activities should be provided by teachers who themselves are adherent to a healthy lifestyle to act as role models to the adolescents, and they should be well-trained communicators with young people in a manner that addresses the emotional and psychological considerations associated with the development of adolescents. Success of the school’s communication with its adolescents via curricular and extracurricular activities should create a culture in schools that reduces stigma associated with body weight and body image and motivate the adolescents to engage in a healthy lifestyle.The current study has several strengths and weaknesses. The main strengths are associated with the utilization of an online platform to enhance the ability to reach adolescents in different weight categories. Additionally, this study was able to identify adolescents who had attempted to lose weight without seeking help from a healthcare professional. The study’s main weaknesses are associated with the likelihood of selection bias due to its online approach and possible measurement bias in relation to the self-reported heights and weights of the participants. Nonetheless, the findings regarding the prevalence of abnormal BMIs and the presence of misperceptions about body weight among adolescents are similar to those reported in the literature locally and internationally.Additionally, this study assessed schools’ contribution to the education of adolescents about healthy eating, physical activity, and their support of weight-loss without involving their teachers or the relevant stakeholders in the education system. Targeting the teachers and the relevant stakeholders is important to ensure objective assessment of school’s contribution to adolescents’ health. This indicates an area for further research to perform an objective assessment of the school’s contribution to a healthy lifestyle in adolescents, via assessing the opinions of the teachers and education system stakeholders concerning healthy lifestyle education among the students. Finally, this study targeted adolescents in one region in Saudi Arabia. Although the education system is unified in the country under the umbrella of the Saudi Ministry of Education, and the teaching system is similar in all regions of the country, it must be noted that the findings of the current study have limited generalizability and further research is required in other regions to assess schools’ contributions towards the education of adolescents about healthy lifestyles.The findings of the current study suggest a suboptimal involvement of schools in the south of Saudi Arabia when promoting healthy eating behaviors and physical activity among students. Furthermore, some adolescents reported not being satisfied with their body weight, which partially explains why some of those classified as underweight or normal-weight had attempted to lose weight in the past three years. Among the adolescents who attempted to lose weight, the most frequently reported source of support was their family. This indicates the need to enhance schools’ contributions to supporting the adoption of healthy lifestyles. Furthermore, governmental and public agencies should establish collaboration between different sectors, such as the health, education, and municipality sectors, as well as families and communities, to tackle body weight abnormality among adolescents and enhance the adolescents’ knowledge about healthy eating, physical activity, and weight loss.


Researchers were tasked with documenting what has been learnt, identifying gaps in knowledge and considering how these might be filled in the future. This report summarises these evidence reviews and interprets them alongside national case studies. It pays particular attention to the context and the constraints on the types of research that could be and were performed during the pandemic.The report is non-judgemental on the timing and manner in which NPIs were applied in different regions and countries around the world. It focuses on understanding the impact of NPIs on SARS-CoV-2 transmission and makes no assessment of the economic or other societal impacts of the different NPIs. Assessing these other impacts are important tasks for the many different COVID-19 inquiries that are underway around the world.Box 1.NPIs include any measure that is implemented during an infectious disease outbreak to attempt to reduce transmission that is not a vaccine or drug. NPIs can be behavioural, social, physical, or regulatory in nature. Their uptake and use can be encouraged through a variety of approaches, escalating from advice and guidance through to regulation. NPIs are therefore the first line of defence in the effort to contain outbreaks and to limit the impacts on affected populations before biological interventions become available. They have also been used alongside vaccines and drugs, especially where these interventions fail to prevent transmission. The precise ways in which NPIs were implemented during the COVID-19 pandemic varied between different countries and contexts.The programme of work covered six broad categories of NPIs and the evidence available concerning their effectiveness at reducing transmission of SARS-CoV-2. The six categories are as follows:Masks and face coveringsMasks act as barriers to virus particles in air being inhaled and/or exhaled through the nose or mouth. Virus-carrying droplets  or aerosols   capturedSocial distancing and ‘lockdowns’Respiratory diseases are transmitted by infectious material carried by exhalations  from one individual to another. Increasing physical distance between individuals can reduce the amount of infectious material being carried to others in droplets and aerosols, although aerosols typically transmit over longer distances than droplets. A commonly recommended minimum distance of separation between individuals during the COVID-19 pandemic was two metres. Interventions on populations and communities included closures of schools, workplaces, places of worship and entertainment venues as well as ‘stay-at-home’ orders ('lockdowns') that prevented most people from coming into contact with anyone outside their own homes.Test, trace and isolateSARS-CoV-2 is transmitted when infected individuals are in close proximity to others. A strategy employed to break the chain of transmission is to identify infectious people ('test'), determine with whom they have come into physical contact ('trace') and encourage or enforce both infected individuals and their contacts to stay at home and avoid physical contact with others until the risk of being infectious has subsided ('isolate').Travel restrictions and controls across international bordersDuring a pandemic, where an infectious disease is spreading across international borders, restricting the ability of people to move between countries can be used to try to prevent the global movement of the pathogen. Border controls applied during the pandemic varied in stringency and took the form of complete or partial bans targeted at international travellers from particular regions perceived as being at higher risk. Often border controls were accompanied by requirements for international travellers to test and/or quarantine at the border of departure and/or arrival to enable some travel.Environmental controlsParticles carrying infectious material vary in size from droplets that settle on surfaces close to the point of exhalation through to very fine aerosols which can linger in the air and travel further. Certain elements of building design and management can be implemented with the intention of restricting the spread of respiratory pathogens. These include enhancing ventilation systems to replace air carrying infectious aerosols with outside air, and filtering or treating air inside buildings to reduce infectious virus. Screens made of a variety of materials and reduced occupancy limits for rooms or buildings can also be used. Environmental controls also include cleaning of surfaces to remove droplets carrying infectious material and enhanced handwashing.CommunicationsEffective communication about any of the physical, social or behavioural interventions is essential if people are to understand and be convinced of the reason for their use, as well as being willing to adopt and maintain the practices, and to do so correctly, so as to maximise effectiveness.From the start of the pandemic, rapidly growing scientific information was deployed continuously to help to control its spread. The genome of the causative virus, SARS-CoV-2, was sequenced from some of the very earliest samples available from infected humans in China. This sequence information enabled the development of precise molecular diagnostic tests that could be used for diagnosis and mass testing of populations, the development of vaccines and continuous monitoring of the evolution of the virus. The development of tests led to the widespread implementation of ‘test, trace and isolate’ interventions early in the pandemic. COVID-19 was the first pandemic in which it was feasible to conduct prophylactic and therapeutic drug trials and to create novel vaccines during the course of the pandemic, saving lives and modifying the outcomes.However, despite extraordinary scientific capabilities, for most of the first year of the pandemic the only measures available to slow the transmission of the novel virus were NPIs. For those that were infected and seriously ill, there were no specific treatments or preventative measures in the form of drugs or vaccines. The supportive measures of modern medicine, such as oxygen supplementation, pulmonary ventilation and other forms of advanced life support, saved many lives, but did nothing to slow transmission.. 2The principles behind NPIs are firmly grounded in prior knowledge about the epidemiology and biology of infectious diseases. In essence, the transmission of an infection from one human to another can be prevented if the transmission pathway can be blocked effectively. For an airborne virus such as SARS-CoV-2, effective measures reduce exposure to virus that has been exhaled by infected people . Measures that can assist, in theory, include the wearing of face masks, enhanced ventilation and social distancing. Where infectious virus survives on surfaces , cleaning regimes including enhanced handwashing can help. Personal protection equipment (PPE), common in healthcare environments  potentially offers protection against exposure.Early clinical studies of COVID-19 strongly suggested that the primary routes for acquiring infection were likely to be by direct inhalation or exposure of the mucosal surfaces of the nose and mouth to virus suspended in airborne droplets or, as was realised some months into the pandemic, in aerosols. Early evidence of fomites (contaminated surfaces), extensively contaminated with SARS-CoV-2 viral nucleic acid shed from infected people, pointed to the possibility that hand-to-face contact might also transmit the infection.This view was informed by prior knowledge of the transmission mechanisms of other respiratory viruses, such as influenza, respiratory syncytial virus (RSV) and the coronavirus (now named SARS-CoV-1) that caused the SARS outbreak in several countries around the world in 2003.. 3Considering the incomplete knowledge about this new viral infection and prior knowledge, many governments around the world implemented measures similar to those used just over a century earlier during the 1918 influenza pandemic. Some countries in Asia implemented measures based on their more recent experience of outbreaks of SARS and Middle East Respiratory Syndrome (MERS).NPIs included the wearing of masks and enhanced personal hygiene measures, including enhanced surface cleaning and handwashing. Social distancing was introduced and enforced to variable extents. Social distancing measures included closures of schools and workplaces, as well as entertainment, leisure and sporting venues. These closures were often augmented by stay-at-home orders for all but essential workers. Border controls and closures were put in place in many countries with the aim of reducing the movement of cases across national borders. The precise measures, and the ways they were implemented, varied between countries according to their social and political-economic contexts and prior experiences.In most of the world, NPIs remained the dominant mechanism for control of the pandemic until well into its second year. The UK was the first country to approve the use of vaccines against SARS-CoV-2, approving three vaccines during December 2020 and January 2021. By July 2021, approximately half of the UK's population had received two doses of vaccine. However, it took until January 2022 for half of the global population to have had two doses – and a year later in January 2023 the global figure had risen to approximately 63% [The challenge for governments around the world facing a pandemic is how to minimise the harms to their populations. The harms of a pandemic are the morbidity and mortality from the viral infection, coupled with the social disruption and harms that follow from the direct and indirect consequences of that morbidity and mortality. The latter can be exceptionally severe if the extent of illness and social response to the illness disrupts the healthcare systems, infrastructure, goods and services on which the health, wellbeing, resilience and security of the population depend.. 4There are two main approaches to generating and analysing evidence about the effectiveness of any intervention intended to alter health outcomes.controlled trials, in which two or more closely matched groups of people are randomised to receive interventions that differ in strictly defined and limited ways. The advantage of this approach is that any changes in health outcome or any side effects of the intervention can be attributed with high confidence to the specific intervention(s).The first and most rigorous approach is to conduct carefully designed One potential disadvantage is that typical controlled trials of new interventions include groups of people amounting at most to a few thousand people in each comparison arm, with participants chosen to enter trials chosen on the basis of very strict criteria. Extrapolating the results of such carefully supervised and monitored studies to much larger and more heterogeneous populations ‘in the real world’ is not straightforward.The intervention may turn out to be less effective in demographically more diverse populations; new and harmful interactions may be discovered when the intervention is provided to people with other conditions or taking other treatments; or rare but important adverse effects may only be discovered when the new intervention reaches a much larger population for the first time.It is possible to conduct randomised controlled trials (RCTs) in populations, through study designs such as cluster-randomised studies, in which populations rather than individuals are randomised to different interventions.observational studies, ideally with large numbers of individual participants, to evaluate a new intervention by comparing the outcomes with similar observational data, which might be: —Historical – for example, examining the outcomes in the same population before and after the intervention; —Geographical – for example, comparing the outcomes in a population receiving the intervention with those in a population not receiving the intervention in a different region of a country or another country; —Modelled – for example, comparing the outcomes in a population receiving an intervention with modelled data projecting the health outcome in the same population in the absence of the intervention, based on prior observed data about the progression of the condition in that population.The observational approach has the advantage that an intervention can be evaluated ‘in the real world’ among very large numbers of people. The disadvantage is that there is a risk that the evidence is less reliable, because it may be confounded by other variables between the different groups under observation .The second approach is to conduct In the case of pharmaceutical and biotechnological interventions during the COVID-19 pandemic, controlled clinical trials of drugs and vaccines were conducted in many countries to examine their clinical effectiveness and to identify the side effects of new therapies and vaccines. The data from these trials formed the basis for licensing decisions by regulators. For example, the RECOVERY Trial enrolled more than 47 000 patients into a rigorously designed trial to test the efficacy of anti-inflammatory and anti-viral treatments to see if these could be repurposed for the treatment of the life-threatening consequences of COVID-19 [ 1.The first was that, in the face of significant knowledge gaps and immediate threats to health and life, the need for urgent actions took precedence over designing and implementing complex trials of NPIs in the absence of pre-prepared protocols. At the beginning of 2020, SARS-CoV-2 infection was spreading rapidly across the world. There was early evidence that respiratory spread was very likely to be the dominant route of transmission. NPIs were the only available steps that might slow or stop the spread of infection. These measures were known to be most likely to be effective when applied when infection numbers were still low. So, it was not a dominant consideration for policymakers to undertake prior formal evaluation of NPIs before their large-scale implementation. 2.The second reason was that that NPIs were typically implemented at a national scale, and applied in combinations on the grounds that NPIs would be expected to be complementary in their actions, e.g. masks + handwashing + social distancing + good ventilation. These measures were augmented by local or large-scale ‘lockdowns’ as numbers of cases rose. As soon as accurate diagnostic tests became available at scale, it became feasible to undertake large-scale testing, tracing and isolation of infected individuals and their contacts. These policy approaches to limiting the transmission of SARS-CoV-2 made trials to investigate the efficacy of individual NPIs almost impossible to implement. 3.The third reason was that excellent and rigorous protocols for controlled studies of drugs, vaccines and other biomedical interventions were available ‘off the shelf’. By contrast, similar trials for complex interventions with strong social and behavioural elements are harder to design and implement and historically have been carried out much less frequently. An adequate design for studying the efficacy of NPIs would have needed to include measures of their desired impact in reducing SARS-CoV-2 transmission alongside measures of their potential undesirable impacts on a large variety of personal and societal variables. These ranged from the mental and physical health consequences of social isolation to the consequences of loss of education, jobs and businesses, and broader economic impacts.This approach to the implementation of NPIs, which largely precluded formal large-scale comparison studies of the effects of different individual NPIs, or of any deliberate comparisons between the effect of packages of NPIs and that of using no NPIs, meant that there were no easy means of evaluating their uptake and effectiveness. There were very few studies of adequate scale to achieve reliable results that compared different types of NPI or that were able to compare, for example, the presence or absence of mask-wearing, or that could measure the effects of different levels of social distancing.In comparison, controlled trials played a relatively small role in the evaluation of NPIs during the pandemic. There were three main reasons for this:There were however a very large number of observational studies that were performed around the world during the pandemic and it is possible to learn a great deal from well-conducted observational studies performed at large scale. Such observational studies were used to explore the effectiveness of stringent social distancing measures, including stay-at-home orders, and closures of work, school, leisure, entertainment, and sporting facilities. In the case of mask usage, there were comparisons in healthcare settings between masks that provided lesser or greater barrier function. International comparisons were also helpful because some countries took markedly different approaches to the use of NPIs, although demographic and other societal differences mean that these should be interpreted with caution.. 5For the purpose of this report, two approaches were taken to considering the evidence accrued during the pandemic on the effectiveness of NPIs. The first approach was to conduct six evidence reviews –10 examiThe second approach was to examine observational data on SARS-CoV-2 infections from three of the small number of regions or countries around the world where cases associated with domestic transmission were first identified in early 2020 and were subsequently contained at very low numbers for approximately the first 18 months of the pandemic. These were Hong Kong, New Zealand and South Korea. In each of these, stringent packages of NPIs were implemented and enforced throughout the pandemic until the second half of 2021. By that time there were large waves of the highly transmissible Delta and Omicron variants of SARS-CoV-2, which caused little harm to the vast majority of those that were fully vaccinated, and their national strategies switched to ‘living with the virus’.post hoc evaluation in mind. Thirdly, comparison groups were not always included and when available, they were rarely well matched. These and other limitations are classified in such evidence reviews as causing potential biases in the outcomes of individual studies. The word ‘bias’, when used in this way, does not have the same meaning as it does when used in common parlance. Specifically, it does not imply that the researchers were biased or partial in seeking a particular outcome for their research, but instead that there were inherent characteristics in the study design that could reduce the reliability of the conclusions of the research. Such biases could result in either overestimation or underestimation of a measured effect.The evidence reviews were undertaken with the aim of establishing the quality and strength of the deductive evidence about the effectiveness of individual NPIs. They were conducted according to a rigorous well-established methodology, which was originally developed to bring together evidence from well-designed clinical trials. When this methodology was applied to observational studies of NPIs it highlighted the inevitable limitations of these studies. Firstly, because interventions were almost invariably implemented in combinations, it was extremely hard to distinguish and measure the effects of any single intervention independently of the others. Secondly, many studies used routinely collected data sets, which were not designed with The evidence reviews focused on the effectiveness of NPIs in relation to the transmission of SARS-CoV-2 infection . They diBox 2.Masks and face coveringsThe weight of evidence from all studies suggests that wearing masks, particularly higher quality masks (respirators), supported by mask mandates, generally reduced the transmission of SARS-CoV-2 infection. Studies consistently, though not universally, reported that mask wearing and mask mandates were an effective approach to reduce infection. There is also evidence, mainly from studies in healthcare settings, that higher-quality ‘respirator’ masks (such as N95 masks) were more effective than surgical-type masks. The evidence suggested that masks with greater barrier function were more effective than those with lower barrier function; and mask wearing in the context of a mandate to wear masks was more effective than mask wearing in the context of voluntary behaviour.Social distancing and ‘lockdowns’Most effective of all the NPIs were the social distancing measures. Stay-at-home orders, physical distancing, and restrictions on gathering size were repeatedly found to be associated with significant reduction in SARS-CoV-2 transmission, with more stringent measures having greater effects. Early in the pandemic certain sub-populations, such as the elderly, were found to be particularly vulnerable to severe disease and death resulting from SARS-CoV-2 infection. Social distancing measures aimed specifically at protecting the elderly, such as restrictions on visitors and ‘cohorting’ staff with residents in care homes , were frequently associated with reduced transmission and reduced outbreaks within care homes. Regarding school closures and other school-based measures, the evidence suggests that they were associated with reduced COVID-19 incidence within schools and the community. However, the effectiveness of these measures was varied (compared to community-wide measures such as stay-at-home orders), time-dependent, and often contingent on the adherence to the measures implemented and the targeted age group of school children.Test, trace and isolateTest, trace and isolate approaches were used as a key intervention in many countries, especially those pursuing zero-COVID policies. Studies from several countries that implemented high levels of contact tracing with isolation of infected individuals and their contacts found reductions in COVID-19 deaths. Strong evidence was also found for the effectiveness of contact tracing apps. For example, a trial of the UK's app  on the Isle of Wight was associated with a substantial reduction in transmission .Travel restrictions and controls across international bordersObservational evidence from national case studies, including New Zealand, showed that comprehensive border control policies could reduce but not eliminate the number of infected travellers or their contacts at the borders entering the country. However, despite most countries introducing travel restrictions during the COVID-19 pandemic, few studies have been published so far examining the effectiveness of these measures when implemented alone. Based on the available evidence, symptomatic or exposure-based screening, including temperature screening before travel, was found to have had no meaningful effect on reducing importation or transmission. Targeted travel restrictions including banning entry early in the pandemic from specific countries probably had a moderate effect on transmission but quickly became less effective once the number of cases rose, whereas quarantine at entry borders was found to have the highest levels of effectiveness.Environmental controlsThe review found evidence that enhanced ventilation, air treatment to remove infectious virus and reduced room occupancy did reduce transmission within particular settings. However, these measures were typically applied in combination with other NPIs, so accurately and individually quantifying their effectiveness was not possible. Many were observational studies conducted retrospectively rather than planned prospectively. As a consequence the studies were unable to control fully for possible confounding factors. It is also the case that the effectiveness was only judged within the setting in which the control was applied, and not at the wider population level. There was insufficient evidence to judge the effectiveness of enhanced surface cleaning or the use of barriers. These are important gaps where laboratory studies could help provide insight.Impact of communication in the UK on uptake of NPIsCommunications in this review were considered specifically in the UK context because political, social and cultural differences make it extremely hard to extrapolate findings about the effectiveness of communications from one country to another. The limited evidence confirmed that communication was sufficiently effective to ensure high adherence to NPIs, although also identifying the characteristics that led to non or less rigorous adherence. Trust and confidence in those communicating was important as was the clarity and consistency of the messaging and the opportunity for personal control. The limited evidence suggests that social media communications are less likely to be associated with higher adherence than those via the traditional media.. 6There are important lessons to be learnt from how different nations implemented NPIs to control the transmission and spread of SARS-CoV-2. The implementation of NPIs differed between and within different countries by time, region, and stringency. There were prominent differences in the timing and intensity of test and tracing, social distancing and ‘lockdown’ measures. Asian countries that had more recently experienced SARS and other emerging infectious diseases, including MERS and avian influenza, such as China, Hong Kong, Taiwan, Singapore, South Korea and Vietnam, used that experience to take a strategic approach aimed at reducing transmission and thereby slowing the spread of infection as quickly as possible. These countries implemented early stringent NPIs, followed by Australia and New Zealand .Three case studies from Hong Kong, New Zealand and South Korea ; strict test, trace and isolate measures; and local or national ‘lockdowns’ when domestic transmission was detected or at high risk of occurrence.This approach controlled the initial outbreak of COVID-19 in New Zealand, where the first recorded case was on 28 February 2020. By 8 June 2020, all domestic NPIs had been lifted and a total of 1504 cases and 22 deaths had been recorded. New Zealand remained mostly transmission-free until late 2021, despite regular positive tests among quarantined international arrivals.The more transmissible Delta variant of SARS-CoV-2 was first detected in August 2021. By this stage the population of New Zealand was highly vaccinated and facing an increasing number of daily cases and the prospect of an extended ‘lockdown’, the government declared the end of the elimination strategy on 4 October 2021.Whilst local NPIs were eased at this time, strict border controls remained in place. In mid-December, the highly transmissible Omicron variant was first detected in entering travellers. Community transmission was not identified until 23 January 2022, and this was followed by a large wave of Omicron infections across New Zealand.South KoreaSouth Korea had experienced an outbreak of MERS in 2015 in which there were 186 cases and 38 deaths. This experience had prompted significant policy reform for pandemic preparedness. Testing infrastructure was well established and ready to be rolled out nationwide in drive-through testing facilities. Testing provided effective estimates of caseload in the country and was coupled with innovative use of technology to great effect. Global Positioning System (GPS) data from mobile phones were used to monitor movements of citizens who were alerted if they had been near a confirmed COVID-19 case and instructed to isolate. Arrivals from other countries were quarantined for 14 days at the border and those from Hubei in China were banned outright.Citizen compliance with policies designed to mitigate transmission was also demonstrably higher than it had been during the MERS outbreak, suggesting that the population was more conscious of the risks around an emerging respiratory disease. The early adoption of these packages of NPIs contained the pandemic effectively and meant that an early ‘lockdown’ was avoided.These national and regional case studies show that it was possible, in certain contexts, to control transmission of SARS-CoV-2 for over a year by implementing early, stringent border controls accompanied by other strict NPIs to prevent and control domestic transmission. They also demonstrate that the effectiveness of NPIs varied inversely in relation to the transmissibility of the infection. As the pandemic progressed, the evolution of increasingly transmissible variants, particularly Omicron, became harder and harder to control using even the most stringent application of NPIs. However, by this point in the pandemic, effective vaccines were becoming widely available and countries pursuing ‘zero-COVID’ strategies switched to policies of high vaccine coverage and ‘living with COVID’. This adjustment was seen in all three of the country case studies, despite early success in containing the pandemic.However, the results reported in the three national and regional case studies cannot simply be replicated in other countries and regions. The national and regional contexts for NPIs varied significantly around the world, according to geographical, political, demographic, socio-economic and regulatory factors. The nature of the national implementation of NPIs and their resulting effectiveness can only be understood in the context of a series of other extremely important interacting factors.Cross-country comparisons of the effectiveness of NPIs are affected by multiple factors, most notably differences in demographic factors, healthcare systems, levels of economic prosperity, degrees of trust between citizens and public authorities, and testing and reporting of cases of COVID-19. Different countries or regions were differentially affected by COVID-19 with particular impacts on those with older populations;  higher lCountries also differed in their categorisation of COVID-19 deaths. For instance, Belgium included all deaths where COVID-19 was suspected to contribute, resulting in higher reported death rates early in the pandemic , while o. 7There is clear evidence from studies conducted during the pandemic that the stringent implementation of packages of NPIs was effective in some countries in reducing the transmission of COVID-19. There is also evidence for the effectiveness of individual NPIs, although, especially as the pandemic progressed and the virus became more transmissible, NPIs became less effective in controlling the transmission of SARS-CoV-2.A common denominator of the evidence from the studies of individual NPIs and from the national case studies is that NPIs were, in general, more effective when the case numbers and the associated transmission intensity of SARS-CoV-2 were lower. This is because the size of the exposure, and therefore the risk of infection, of uninfected, non-immune people to viral infection is proportional to the number of cases in the community. Similarly, the stringency of the application of individual NPIs and groups of NPIs was important, so there was evidence that respirator masks were more effective than surgical masks and that two weeks of quarantine were more effective than shorter periods.. 8There are important lessons for the future. For policymakers and their professional advisers, there is a need to learn from national and international experience of the implementation of NPIs during the COVID-19 pandemic, and to understand in detail the differing national contexts and ways in which NPIs were implemented. National context was an important influence on the outcome of the COVID-19 pandemic.For researchers and their funders, there is a lesson that observational studies can be facilitated if national and international collaborations can be established in advance of a future pandemic, with standardised protocols for data collection. While RCTs should not be discounted, it is highly likely that most information in a future pandemic will continue to be observational. It should be possible to exploit more effectively, for the purposes of evaluation, the consequences of differences in the implementation of NPIs within and between countries and this would be much easier to achieve if protocols could be prepared in advance. So for the future, it is important to design protocols for observational research that can disaggregate the effects of NPIs by social groups and other demographic factors within countries.Future assessments should also consider the costs as well as the benefits of NPIs, in terms of their impacts on livelihoods, economies, education, social cohesion, physical and mental wellbeing, and potentially other aspects. Drug regulators are able to make recommendations on the use of drugs based upon evidence of their effects and side effects. Similarly, policymakers will be able to make the best policy decisions on NPIs, which are in the main complex social interventions, if they have access to better evidence regarding their broader health and societal impacts. They could consider these alongside their effects on reducing the transmission of the infectious agent. The provision of such evidence will require pre-planned protocols, and in some cases prior research, to collect a wide variety of relevant health and social data systematically and, alongside this, an embedded system of expert research advice to assist policymakers in making extremely difficult policy decisions in the face of a severe pandemic.The evidence assembled for the development of this report shows that, in the context of COVID-19 that was caused by a virus dominantly transmitted by a respiratory route, controlling the transmission of the virus required a clear plan for the stringent application of combinations of NPIs.One of the most important lessons from this pandemic is that it proved possible to influence the outcome of the COVID-19 pandemic by means of the rapid development, evaluation and implementation at scale of specific treatments and vaccines. The effective application of NPIs ‘buys time’ to allow the development, evaluation and manufacturing of such therapies and vaccines at scale. So there is every reason to think that the application of combinations of NPIs will be important in future pandemics, particularly at early stages with novel pathogens when there are knowledge gaps and when therapeutics and vaccines are not yet available.


This research analyses the viability of using cryogenic cooling combined with MQL (minimum quantity lubrication) lubrication, under CryoMQL technology, as a cutting fluid in the industrial environment to justify the increase in the environmental footprint generated by its use compared to MQL in stand-alone mode. For this analysis, a set of milling tests were carried out on carbon steel AISI 1045, which is one of the most commonly used materials in the business day-to-day. In this set of tests, the evolution of cutting edge wear and energy consumption of both technologies were recorded to check their tool life through technological and environmental analysis. Thus, we sought to discern whether the energy savings derived from the machining process make up for the greater environmental footprint initially generated by the use of CryoMQL technology itself. The results obtained show how the use of CryoMQL not only increased tool life, but also allowed an increase in productivity by increasing cutting speeds by 18%; in other words, thanks to this technology, a more technologically advanced and environmentally friendly process is obtained. By increasing tool life by 30%, a reduction in energy consumption is achieved together with cost savings, which implies that ECO2 machining has economic and ecological benefits. Faced with the necessity of reducing the use of conventional (flood) cutting fluids, the machining sector’s current aim is the environmental enhancement of production processes by replacing conventional oil emulsion with ecofriendly coolant methods, such as minimum quantity lubrication (MQL) or cryogenic cooling. The cost of cutting fluid can account for up to 17% of manufacturing budgets, surpassing even the cost of cutting tools [Pereira et al.  analyzedThe principal goal of MQL is minimizing the amount of cutting fluid required to maintain the accuracy and efficiency of manufacturing processes. MQL involves the use of microparticles of oil, which obtain a mist into the cutting area. This technique combines air pressure and a minimal amount of oil, while the air is using for cooling and the oil is used as lubricant as it reduces friction . Through2) and carbon dioxide liquefied (CO2). Cryogenic cooling provides the heat sink required to reduce the tool temperature, while MQL reduces the cutting energy [The main objective of cryogenic cooling is to reduce the temperature in the cutting area, guaranteeing a greater stability in this zone and allowing an increase in the cutting speed during machining; two of the most used fluids in this process are liquid nitrogen  Tescan Vega 4 Compact® with the aim of measuring the wear and any possible adhesion.During the tests, the cutting forces were recorded using a triaxial dynamometer table KistlerThe cutting conditions used are shown in 2 cryogenic using an injection pressure of 10 bar, achieving a biodegradable oil aerosol cryogenized which, once it reached the tool tip, had a cutting temperature of −78 °C. To achieve this effect, a special tool holder was used, which allowed the combining of both fluids without freezing the biodegradable microparticles; it then achieved the cutting tool tip. The test’s setup is shown in Regarding the cutting fluids used, MQL and CryoMQL techniques were compared. In the case of MQL technology, a canola biodegradable oil was sprayed with a flow rate of 100 mL/h. In the case of CryoMQL lubricooling technique, MQL was combined with COMachinability criteria, such as cutting temperature, surface integrity, surface roughness, etc., are dependent on tool wear; therefore, the research focused on the wear produced along the machining, while the cutting force was analyzed because the two factors are directly related. When faced with an increase in the tool wear, the cutting forces also grew.After the cutting forces analysis, the wear obtained throughout the test was analyzed. During the test, several images of the inserts were taken to analyze the tool. Above all, the wear before and after the changes in the cutting conditions were analyzed. This study stage was the most interesting as, in the face of an increase in productivity, it was also possible to reduce energy consumption. As shown in By analyzing the images taken during the test shown in Once tool wear images obtained with the PCE-200 microscope were analyzed, a tool wear analysis was carried out with the SEM microscope to obtain more precise images, verify the materials of which the coating was composed and observe the adhesion in the tool wear area in more detail.Firstly, in Finally, we also analyzed the tool wear under CryoMQL conditions. The results obtained are shown in This measurement verifies results obtained through microscopy as it allows for the observation of the wear produced in the insert and the adhesion phenomenon. In the case of MQL, adhesion is greater after machining 6300 mm and starting with more aggressive cutting conditions, such as a cutting speed of 380 mm/min.2 and, thus, an increase in the environmental footprint in comparison with the MQL lubrication technique, its use allows increasing cutting speed and, therefore, reduces manufacturing times without increasing energy consumption. The CryoMQL technique is, thus, a more technologically efficient process, which can be introduced into industrial facilities with aim of advancing towards an ECO2 manufacturing process.Therefore, taking into account the parameters analyzed, it is shown that the use of CryoMQL lubricooling technique balances environmental and technical issues. In particular, although using CryoMQL implies the use of COIn this research, CryoMQL technology influence was compared with MQL one in AISI 1045 carbon steel milling. The use of CryoMQL lubricooling technique improved the cutting conditions without increasing mechanical stresses on the tool.The cutting forces are similar in both tests, which means that CryoMQL technology does not increase energy consumption;The results obtained show how the use of CryoMQL technology implies an increase in productivity through an 18% increase in cutting speed, which implies a reduction in manufacturing times;Joining the previous advantage with an increase of 30% in the tool life, which is directly related to cost reductions, can be considered a great improvement for the machining sector. By reducing the use of inserts, it is also possible to reduce their environmental footprint during both the machining and production processes;During the tests, adhesion was obtained on the edge of the tool using MQL, which reduced the tool’s stability. On the other hand, using CryoMQL technology, the wear caused in the cutting edge was more homogeneous;The adhesion produced during the MQL test was verified with the SEM; when checking the composition in that area, a large increase in iron was observed, whereas in CryoMQL technology a similar increase did not happen. Thus, with the use of CryoMQL technology, adhesion phenomenon was reduced drastically.All in all, the following conclusions can be drawn from the tests carried out:Therefore, taking into account the results obtained, the medium-term viability of using cryogenic cooling combined with MQL lubrication as a cutting fluid in the industrial environment can be achieved without affecting current productivity.


Desulfovibrio, can be better understood if the antimicrobial role of the virgin olive oil polyphenols is considered.Extra virgin olive oil (EVOO) has proven to yield a better health outcome than other saturated fats widely used in the Western diet, including a distinct dysbiosis-preventive modulation of gut microbiota. Besides its high content in unsaturated fatty acids, EVOO also has an unsaponifiable polyphenol-enriched fraction that is lost when undergoing a depurative process that gives place to refined olive oil (ROO). Comparing the effects of both oils on the intestinal microbiota of mice can help us determine which benefits of EVOO are due to the unsaturated fatty acids, which remain the same in both, and which benefits are a consequence of its minority compounds, mainly polyphenols. In this work, we study these variations after only six weeks of diet, when physiological changes are not appreciated yet but intestinal microbial alterations can already be detected. Some of these bacterial deviations correlate in multiple regression models with ulterior physiological values, at twelve weeks of diet, including systolic blood pressure. Comparison between the EVOO and ROO diets reveals that some of these correlations can be explained by the type of fat that is present in the diet, while in other cases, such as the genus  For several years, studies have dealt with the influence of the intestinal microbiota and the health of the gut environment on the development of obesity, metabolic, and even neurodegenerative diseases through the gut–brain axis ,2,3. DieOlive oil is not the most widely consumed oil in the world , but it has always been the principal fat added to the Mediterranean diet. Extra virgin olive oil (EVOO) is a functional food with a wide variety of healthy components, such as monounsaturated fatty acids and phenolic compounds, with beneficial effects on cardiovascular diseases due to their anti-inflammatory and antioxidant activities , and it Several studies propose that the anti-inflammatory, antitumor, antioxidant, and modulatory effects of the intestinal microbiota (associated with this diet and the EVOO) on chronic inflammatory diseases could be attributed to polyphenols . In There are few studies about the influence of ROO on health and none on the intestinal microbiota. Because of this, our research team set out to study this fact, finding different behavior in ROO compared to EVOO as well as a different microbial profile when analyzed by denaturing gradient gel electrophoresis (DGGE) . SubsequHowever, correlation is not causation, and in order to clarify if variations in the microbial taxa had an effect on their correlating physiological variables or if they both just changed concomitantly under the impact of the diet, we studied the results obtained in the middle of the experiment, after only six weeks of diets, comparing them with each other and also with the ones obtained at twelve weeks. Results comparing EVOO and butter at six weeks showed that several changes in the microbial composition at this time point have regression coefficients that are statistically significant with metabolic and physiological variables at twelve weeks, even though some of the taxa did not maintain statistical significance by the end of the experiment . This isIn the current research, the results obtained at six weeks under the EVOO and the ROO diets were compared in order to find out which of these EVOO-driven differences have their origin in the polyphenol content lost in ROO, and the data could give information on the possible role of the intestinal microbiota in the final outcome of these diets.p-value of 0.004 (p = 0.057), with lower values in EVOO and also in ROO (ANOVA test) , with a of 0.004 a. WeightVA test) b, with aAfter sequencing the 35 samples until the number of reads was stable, and after trimming and filtering, 353,260 sequences were obtained with a mean length between 548 and 575 nt and a total amount of 196.91 MB. In order to associate an organism with each sequence obtained, a blast search was performed, and the reads were grouped based on family, genera, and species levels. In total, sequences were classified into 9 phyla, 89 families, 227 genera, and 538 species.Tenericutes and Proteobacteria showed significant differences  with greater values in EVOO against SD  with the phyla Tenericutes and Proteobacteria . Since we also had available the physiological measurements at the end of the experiment, already reported in Prieto et al. [When a Kruskal–Wallis test was used to check if the distributions of the diverse phyla  were theainst SD . Howevero et al. , we repeAcetobacteriaceae) was it significantly different from the EVOO diet. The same procedure was repeated at the family level. According to the Kruskal–Wallis test, out of the 89 families that were detected, twelve of them showed statistically significant differences among the four diets; in eight of them, the ROO diet was significantly different in a multiple pairwise analysis, but only in one case , EVOO was statistically significantly different from BT and ROO. Multiple regression models were drawn and only three were found that fully complied with all the hypotheses required, one on SBP at six weeks that involved Bacteroides finegoldii  and two at 12 weeks for FI, involving Rikenella microfusus  and for WI involving Marispirillum indicum .Finally, species were also studied. In this case, since the number of species was too high, we centered our attention on those showing differences with statistical significance between BT and EVOO in order to check how ROO clustered in those cases. Four species fulfilled this premise, and the comparisons are shown in Desulfovibrio sequences in feces, increasing under a butter-enriched diet but not doing so under an EVOO-enriched one [Desulfovibrionaceae, being again the genus Desulfovibrio preeminent since EVOO and ROO had an opposite influence on its percentage in a multiple pairwise comparison analysis. These data allowed us to discuss whether EVOO polyphenols and unsaponifiable matter, in general, could be responsible for all the EVOO effects on the bacterial taxa that were not duplicated in the ROO experimental group.Previously, we have shown that different high-fat diets have diverse effects on the intestinal microbiota of mice . We haveched one . Consequched one , includiDesulfovibrio had an important role in the discussion because it was again less prominent in the EVOO group at six weeks and showed a significant regression coefficient with body weight, food intake, water intake, and systolic blood pressure measured at 12 weeks of diet.All these results were measured after 12 weeks of diet when physiological changes were more visible. However, we had the opportunity to study the microbial intestinal environment and the physiological health of the same mice but six weeks earlier, in the midterm balance of the experiment. This analysis was performed, and comparisons and multiple regression models were drawn between the SD, BT, and EVOO groups not only at six weeks but also with the physiological and metabolic variables measured at the end of the experiment at 12 weeks . CertainIn the work we present now, we have made the analysis, adding the data obtained in the group of mice fed a refined olive oil-enriched diet at six weeks of experiment in order to derive the role of the polyphenols at this time point in the feeding process. The aim is to uncover which changes in the intestinal microbiota prompted by an EVOO diet at this time are due to its fatty acid composition and which ones are influenced by its minority compounds, and moreover, if these relations have any manifestation after a further six weeks.With respect to the physiological variables, the only significant difference is found in systolic blood pressure, and in a relative manner. We had already reported significantly low SBP values in the EVOO group with respect to the BT and SD groups, neither of which maintained excessive SBP nor a difference between them . If thisTenericutes profile and unlike it in Proteobacteria, where ROO clusters with BT. Proteobacteria is quite dominant in the butter group at twelve weeks [Acetobacteriaceae), while in the other four, either EVOO (Christensenellaceae and Enterobacteraceae) or ROO (Spiroplasmataceae and Staphylococcaceae) was significantly different from SD while the other unsaturated fat was not, even though the two fat profiles were similar. In the rest of the families, seven in total, EVOO and ROO had an identical statistical outcome. Moreover, in four of these seven families , BT behaved statistically different from both EVOO and ROO, while in another (Lactobacillaceae), the three high-fat diet groups had percentages significantly lower than the SD group, indicating a probable common effect of all types of fat. Six weeks later, at the end of the experiment, the scenario would be totally different, with further differences between both EVOO and ROO in the predominance of the bacterial taxa [When studying the intestinal microbiota at the phylum level, ROO behaves like EVOO in the ve weeks . At the ial taxa . This faSphingobacteriaceae and Spiroplasmataceae are maintained; the model for diuresis keeps only Rhodospirillaceae at six weeks, and the model for blood pressure at twelve weeks maintains only the family Sphingobacteriaceae, although in the case of fam. Spiroplasmataceae, its genus, Spiroplasma, also maintains the statistical significance. Among the regression coefficients that maintain their statistical significance, it is worth noting the relation of the families Lactobacillaceae (direct) and Gracillibacteraceae (inverse) with food intake both at six and at twelve weeks of diet. The fact of losing the significance of some regression coefficients does not diminish their importance in the other three diets because, by including a new diet, new uncontrolled factors can be introduced as well. However, if they are maintained, the result is more robust. In this way, the relationship of lactic acid bacteria with food intake all through the experiment, with and without ROO, makes this a very interesting result, especially because it is not included in the regression model for body weight at any point. However, lactobacilli have previously been related to obesity in humans [Gracillibacteraceae has a direct relationship with body weight at six weeks but a negative one with food intake both at six and 12 weeks, and this result could be related to some kind of regulation when the animal has reached the appropriate weight. In any case, in both families, EVOO and ROO have the same effect, so these outcomes cannot be attributed to the minority compounds. Moreover, in Lactobacillaceae, the three high-fat diets have the same statistical behavior, so it could confirm the effect of HFD in general as discussed previously with only two types of fat [With respect to the regression models found using the significant families as an independent factor, most of the significant regressions already reported in Andújar et al.  are mainn humans , and this of fat .Acetobacteraceae and its genus Oleomonas, whose percentage is significantly lower in the EVOO diet than in the ROO group, with the BT percentage being closer to ROO and the SD percentage being closer to EVOO. The predominance of this family is low, but it is worth mentioning because it is the only one where the two olive oils have a statistically significant opposite profile. This family also happens to correlate with body weight at six weeks and inversely with food intake and water intake at twelve weeks, both without ROO [Acetobacteraceae shares with Sphingobacteriaceae the presence in its membrane of a lipid type that is rare in bacteria, sphingolipids [This is not the case for fam. hout ROO  and withgolipids . They cagolipids . In thisgolipids , where pgolipids . This coRikenella and Desulfovibrio. Rikenella is taxonomically framed in the homonym family, Rikenellaceae, but in this study, both taxa do not share the same profile, and it is another same family genus, Alistipes, which is much more prominent in percentage and the one that maintains the family outcome  and 12 weeks [2S as a reduced outcome and will not participate in some of the mechanisms hypothesized for this bacterium to contribute to a blood pressure increment in the long run [Desulfovibrio in the EVOO diet; this was even more evident over the full term of the experiment when the percentages of this genus in the BT and ROO diets had doubled and EVOO and ROO had significantly different values [Finally, the genus er diets . The genhed diet ,23,24 but growth , and nitt growth . This an12 weeks , since tlong run , althouglong run . In any t values .n = 8) or three high-fat diets  containing SD supplemented with 20% either butter (n = 9) (BT), extra virgin olive oil (n = 9) (EVOO) or refined olive oil (ROO), respectively . Butter and ROO were obtained from a large commercial store . Fatty acid percentage and characterization were performed ; and EVOO polyphenol content was obtained from the producer . All experimental procedures were performed in accordance with the European Communities Council Directive 86/609/EEC and reviewed and approved by the Bioethics Committee of the University of Jaén, initially on 29 December 2010 for project AGR 6340 and extended for project PP2015/08/09. The procedure was followed as described previously ,29,30. A© DNA Stool Kit  as described and reported previously [In order to study the bacterial composition in feces, DNA was extracted using the QIAampeviously ,16,17. TFor the statistical analysis, we followed the procedures described previously ,16,17. WSphingobacteraceae and related taxa, and, therefore, their involvement in the development of the high values in the systolic blood pressure is doubtful. On the other hand, differences in the genus Desulfovibrio under the three HFDs can be better explained if a contribution of this bacterium to the increment of blood pressure values is assumed and the antimicrobial role of the virgin olive oil polyphenols is presumed in the maintenance of low levels of this genus under an EVOO high-fat diet.In summary, there are several bacterial taxa that are significant in regression models for physiological variables related to metabolic syndrome, both in a concomitant way and also after several weeks of high-fat diet feeding. Among these variables, blood pressure is remarkable because its values at twelve weeks can be explained by a multiple regression model with some of these bacteria, but no such model was found for SBP values at six weeks of diet. The different prevalence of some of these bacteria under the three high-fat diets can be easily explained just by the type of fat that is present in the diet, as is the case with the family