Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

BACKGROUND

Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories.

METHODS

We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5-19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For school-aged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median).

FINDINGS

From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness.

INTERPRETATION

The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesity.

FUNDING

UK Medical Research Council, UK Research and Innovation (Research England), UK Research and Innovation (Innovate UK), and European Union.

Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance.

Results from Portugal's 2022 report card on physical activity for children and youth

Background

The purpose of this study is to update results of Portuguese's Report Card on Physical activity (PA) for Children and Adolescents.

Methods

The grades were assigned by results derived from the PA and Fitness in Portugal 2021 Portuguese Report Card and corresponds to the third report for the Portuguese children and adolescents. It includes indicators of PA and sedentary behavior (SB) that are common to the GLOBAL matrix 4.0: Overall Physical Activity, Organized Sport and Physical Activity, Active Play, Active Transportation, Sedentary Behaviors, Family and Peers, School, Community and the Environment, Government and Physical Fitness. The search focused on published national evidence/data sources (academia, NGO, governmental) from end 2018 onwards excluding data obtained during the covid-19 pandemic.

Results

The grades were assigned as follows: Overall PA (D^-), Organized Sport Participation (C^-), Active Play (D⁺), Active Transportation (D^-), Sedentary behaviors (C⁺), Physical Fitness (C), Family and Peers (B), School (A), Community and Environment (B), and Government (B).

Conclusion

In line with previous Portuguese Report Cards, a large proportion of Portuguese children and adolescents are not sufficiently active nor fit enough setting urgency for effective strategies. Particular attention should be given to Active play, Active transport and Organized Sports Participation has their grades have decreased. Some actions in selected indicators as Governmental and policy seems promising however results weren't seen yet. Despite the strong support of schools with mandatory curricula in PE no correspondent change is observed in fitness or PA, so more research is needed to find why.

Diminishing benefits of urban living for children and adolescents' growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1-6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5-19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m-2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.

Associations of accelerometer measured school- and non-school based physical activity and sedentary time with body mass index: IPEN Adolescent study

Background

This study examined the strength, shape and direction of associations of accelerometer-assessed overall, school- and non-school-based moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) with BMI among adolescents across the world. Second, we examined whether these associations differed by study site and sex.

Methods

Cross-sectional data from the IPEN Adolescent study, an observational multi-country study, were used. Participants wore an accelerometer for seven days, reported height and weight, and completed a socio-demographic survey. In total, 4852 adolescents (46.6% boys), aged 11–19 years (mean age = 14.6, SD = 1.7 years) were included in the analyses, using generalized additive mixed models.

Results

Adolescents accumulated on average 41.3 (SD = 22.6) min/day of MVPA and 531.8 (SD = 81.1) min/day of ST, and the prevalence of overweight and obesity was 17.2% (IOTF), but these mean values differed by country. Linear negative associations of accelerometer-based MVPA and ST with standardized BMI scores and the likelihood of being overweight/obese were found. School-based ST and non-school-based MVPA were more strongly negatively associated to the outcomes than non-school based ST and school-based MVPA. Study site moderated the associations; adolescent sex did not. No curvilinear associations were found.

Conclusions

This multi-country study confirmed the importance of MVPA as a potential protective factor against overweight/obesity in adolescents. Non-school-based MVPA seemed to be the main driver of these associations. Unexpected results were found for ST, calling for further examination in methodologically sound international studies but using inclinometers or pressure sensors to provide more precise ST measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01324-x.

The effect of impact exercise on bone mineral density: A longitudinal study on non-athlete adolescents

PURPOSE

High impact exercise is known to induce osteogenic effects in the skeleton. However, less is known about the systemic effect of exercise practice in a potential adaptive mechanism of the skeletal accrual. This research aimed to assess the effect of impact exercise on bone mineral density (BMD) in the radius throughout adolescence.

METHODS

This study evaluated 1137 adolescents, at 13 and 17 years old, as part of the population-based cohort EPITeen. BMD (g/cm²) was measured at the ultradistal and proximal radius of the non-dominant forearm by dual-energy X-ray absorptiometry (DXA) using a Lunar® Peripheral Instantaneous X-ray Image device. The practice of (extra-curricular) exercise was categorized as: no exercise, exercise with high impact and exercise with low impact. Regression coefficients (β) and respective 95% confidence intervals (CI_95%) were used to estimate the association between exercise practice categories at 13 years old and BMD at 13 and 17 years old and BMD gain between evaluations.

RESULTS

In boys, at 13 years, BMD was similar between the ones not practicing exercise and those practicing exercise with low impact, and the gain of BMD was also similar in both groups. Still in boys, at 13 years, those who practiced exercise with high impact presented higher mean (standard-deviation) of BMD, comparing to the other two groups (no exercise and low impact exercise), and also significantly increased the BMD gain between 13 and 17 years (β = 0.013; CI_95%0.003;0.023). In girls, no statistically significant differences on BMD were found between the categories of exercise at 13 years and BMD at 17 years of age.

CONCLUSION

This research shows that the practice of high impact exercise could help to increase BMD more than low impact exercise even in a nonweight-bearing bone during adolescence.

Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants

BACKGROUND

Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories.

METHODS

We used data from 1990 to 2019 on people aged 30-79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age.

FINDINGS

The number of people aged 30-79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306-359) million women and 317 (292-344) million men in 1990 to 626 (584-668) million women and 652 (604-698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55-62) of women and 49% (46-52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43-51) of women and 38% (35-41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20-27) for women and 18% (16-21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran.

INTERPRETATION

Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings.

FUNDING

WHO.

Urban Green Spaces, Greenness Exposure and Species Richness in Residential Environments and Relations with Physical Activity and BMI in Portuguese Adolescents

Environmental factors play an important role in obesity-related behaviors. Evidence indicates significant associations between weight and urban green spaces in adults, but it is not clear whether this relationship applies to adolescents. Therefore, our aim was to determine the associations between urban green spaces, greenness exposure and species richness in residential environments with physical activity and body mass index. Sixty-two adolescents between 12 and 18 years of age answered a self-administered questionnaire, providing information on height, weight, age, sex and home address. Data on socioeconomic deprivation were obtained from the European Index of Deprivation for Small Portuguese Areas. Physical activity levels were assessed using accelerometers. Urban green space counts and the normalized difference vegetation index values were measured using buffers along the roads with distances of 300, 500, 1000 and 1500 m from each participant's residence. To quantify the species richness, the species richness index was used. Linear regression models were fitted to analyze whether urban green spaces, exposure to green spaces and species richness counts for each distance were associated with physical activity and self-reported body mass index. We did not find significant associations between the independent variables and the probability of overweight or obesity. The relationship between environmental variables, adolescents' physical activity and body weight seems to be complex and further studies may contribute to better understanding of the topic.

Increased expression of interleukin-6 gene in gastritis and gastric cancer

Helicobacter pylori (H. pylori) induces an intense inflammatory response, mediated by proinflammatory cytokines, including interleukin (IL)-6 and its membrane receptor (IL-6R), which activates important signaling pathways in the development of gastric disease and cancer. We investigated the gene and protein expression of IL-6 and IL-6R and the influence of polymorphisms rs1800795, rs1800796, and rs1800797 on its gene expression together with H. pylori infection. Furthermore, an in-silico analysis was performed to support our results. Gastric biopsies were obtained from patients with gastric symptoms and patients with gastric cancer (GC) and were divided into groups (Control, Gastritis, and Cancer). H. pylori was detected by PCR. Real-time-qPCR was employed to determine gene expression, and western blot assay was used to analyze protein expression levels. PCR-RFLP was used to characterize IL-6 polymorphisms. Bioinformatics analyses were performed using the Gene Expression Omnibus (GEO) database and GEO2R to screen out differentially expressed genes (DEGs). H. pylori was detected in 43.3% of the samples. Statistically significant differences were found for IL-6 (P=0.0001) and IL-6R (P=0.0005) genes among the three groups, regardless of the presence of H. pylori. Among patients with H. pylori infection, the IL-6 and IL-6R gene and protein expressions were significantly increased, highlighting IL-6 gene overexpression in patients with GC. No statistically significant differences were found for the rs1800795, rs1800796, and rs1800797 polymorphisms compared to IL-6 gene expression. The results indicated that the IL-6 polymorphisms do not influence its expression, but IL-6 and IL-6R expression seems to be altered by the presence of H. pylori.

Use of Formal and Informal Food Resources by Food Insecure Families in Lima, Peru: A Mixed-Methods Analysis

The goal of this study was to measure food insecurity among families with children in a low-income district of Lima, Peru and to identify the formal and informal food resources available to them that may affect their food security status. In June-July 2019, we collected data from 329 randomly selected households in Villa El Salvador (Lima, Peru). Following a mixed methods approach, we found that the percentage of households using food assistance programs (FAPs) increased with increasing levels of food insecurity, but two FAPs were heavily used by households regardless of food (in)security. The main reasons for using FAPs included financial need, already being signed up in the program, and believing that the food was of nutritional value; the main reasons for non-use were finding the program unnecessary, dislike or poor perceived quality of the food, and not being able to sign up for the program. Similarly, informal food resources, such as buying food on credit or receiving food from someone outside the household, were incrementally used with increased levels of food insecurity. Our study clarifies the relationship between level of household food insecurity and FAP use – FAPs more commonly used by food insecure households were used because of financial need, whereas the FAPs most commonly used by food secure households were those with automatic enrollment. At a programmatic level, our research highlights the need for making nutritious and preferred foods available in FAPs and standardizing the application of enrollment criteria.

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.

International Physical Activity and Built Environment Study of adolescents: IPEN Adolescent design, protocol and measures

INTRODUCTION

Only international studies can provide the full variability of built environments and accurately estimate effect sizes of relations between contrasting environments and health-related outcomes. The aims of the International Physical Activity and Environment Study of Adolescents (IPEN Adolescent) are to estimate the strength, shape and generalisability of associations of the community environment (geographic information systems (GIS)-based and self-reported) with physical activity and sedentary behaviour (accelerometer-measured and self-reported) and weight status (normal/overweight/obese).

METHODS AND ANALYSIS

The IPEN Adolescent observational, cross-sectional, multicountry study involves recruiting adolescent participants (ages 11-19 years) and one parent/guardian from neighbourhoods selected to ensure wide variations in walkability and socioeconomic status using common protocols and measures. Fifteen geographically, economically and culturally diverse countries, from six continents, participated: Australia, Bangladesh, Belgium, Brazil, Czech Republic, Denmark, Hong Kong SAR, India, Israel, Malaysia, New Zealand, Nigeria, Portugal, Spain and USA. Countries provided survey and accelerometer data (15 countries), GIS data (11), global positioning system data (10), and pedestrian environment audit data (8). A sample of n=6950 (52.6% female; mean age=14.5, SD=1.7) adolescents provided survey data, n=4852 had 4 or more 8+ hours valid days of accelerometer data, and n=5473 had GIS measures. Physical activity and sedentary behaviour were measured by waist-worn ActiGraph accelerometers and self-reports, and body mass index was used to categorise weight status.

ETHICS AND DISSEMINATION

Ethical approval was received from each study site's Institutional Review Board for their in-country studies. Informed assent by adolescents and consent by parents was obtained for all participants. No personally identifiable information was transferred to the IPEN coordinating centre for pooled datasets. Results will be communicated through standard scientific channels and findings used to advance the science of environmental correlates of physical activity, sedentary behaviour and weight status, with the ultimate goal to stimulate and guide actions to create more activity-supportive environments internationally.

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

BACKGROUND

Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents.

METHODS

For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5-19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence.

FINDINGS

We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9-10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes-gaining too little height, too much weight for their height compared with children in other countries, or both-occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls.

INTERPRETATION

The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks.

FUNDING

Wellcome Trust, AstraZeneca Young Health Programme, EU.

Neighborhood environmental factors associated with leisure walking in adolescents

OBJECTIVE

To verify the associations of leisure walking with perceived and objective measures of neighborhood environmental factors stratified by gender and socioeconomic status (SES) in Brazilian adolescents.

METHODS

Cross-sectional study with a random sample of 1,130 high school students (47.3% girls; aged 14 to 20 years old) from Porto Alegre, Brazil. Leisure walking and SES were self-reported by the adolescents. Perceived environmental factors were assessed through Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Objective measures were evaluated using Geographic Information Systems, with road network calculated around the adolescent’s residential address, using 0.5km and 1.0km buffers. Data collection was carried out in 2017 and generalized linear regression models were used.

RESULTS

Leisure walking was positively associated with access to services (0.5 km buffers [Odds ratio (OR) = 2.22] 1.0 km buffers [OR = 2.17]) and lower distance to parks and squares (0.5 km [OR=2.80] 1.0 km [OR = 2.73]) in girls from low SES. Residential density (0.5 km [OR = 1.57] 1.0 km [OR = 1.54]) and walkability index (0.5 km [OR = 1.17] 1.0 km [OR = 1.20]) were associated with leisure walking in girls from middle SES. Boys from low SES showed an inverse association between crime safety and leisure walking (0.5 km [OR = 0.59] 1.0 km [OR = 0.63]). Neighborhood recreation facilities was positively associated with leisure walking in middle SES (0.5 km [OR = 1.55] 1.0 km [OR = 1.60]). Land use mix (0.5 km [OR = 1.81] 1.0 km [OR = 1.81]), neighborhood recreation facilities (0.5 km [OR = 2.32] 1.0 km [OR = 2.28]) and places for walking (0.5 km [OR=2.07] 1.0 km [OR=2.22]) were positively associated with leisure walking in high SES.

CONCLUSION

Environmental factors (objectively and subjectively measured) and leisure walking show association in boys and girls of different SES.

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular risk-changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.

Low concentrations of glyphosate-based herbicide cause complete loss of sperm motility of yellowtail tetra fish Astyanax lacustris

Environmental relevant concentrations of glyphosate-based herbicide as 50 µg l-1 , 300 µg l-1 and 1800 µg l-1 can affect sperm quality of yellowtail tetra fish Astyanax lacustris. Viability of sperm cells was impaired at 300 µg l-1 , a concentration that is within legal limits in U.S.A. waterbodies, while motility was impaired at 50 µg l-1 , which is the more stringent limit set in Brazilian law. Therefore, environment protection agencies must review regulations of glyphosate-based herbicides on water bodies.

Association of TNF -1031 C/C as a potential protection marker for leprosy development in Amazonas state patients, Brazil

Polymorphisms present in the TNF promoter region has shown to influence the gene transcription. Leprosy displays different clinical manifestations according to the immune responses of the individual infected with Mycobacterium leprae. In this study, we evaluated the single nucleotide polymorphisms (SNPs) -238 G/A (rs361525), -308 G/A (rs1800629), -857 C/T (rs1799724), -863 A/C (rs1800630) and -1031 T/C (rs1799964) in the promoter region of the TNF to see whether these SNPs influence host-susceptibility to leprosy and the different clinical manifestation. Nucleotide sequencing was performed with DNA samples from 108 leprosy patients and 253 control subjects. An association between -1031 C/C genotype and protection from leprosy was observed when leprosy patients were compared to controls (OR 0.11; 95% CI=0.01-0.82; p=0.012). The -857 C/T genotype may be associated with susceptibility to leprosy (OR=1.81; 95% CI=1.09-3.00; p=0.028). Similar genotype and allele frequencies for the SNPs -308 G/A and -238 G/A were observed between leprosy patients and control subjects. Altogether, TNF polymorphisms in the promoter region may be predictive of leprosy outcome.

Which social support and psychological factors are associated to active commuting to school?

OBJECTIVE

The aim of this study was to investigate the association between self-efficacy, enjoyment, and volitional control with active commuting, as well as to analyze the impact of social support from parents, friends, and teachers with active commuting to school.

METHODS

Participants in this cross-sectional study were 625 students (male: 46.3%) aged 10 to 15years from Porto, Portugal (2010/2011). A questionnaire was used to assess active commuting to/from school (walk/cycle), self-efficacy, enjoyment, volitional control and social support. Binary logistic regression was performed to identify significant associations between targeted variables and active commuting.

RESULTS

The results show positive associations in crude analyses for all variables, except for enjoyment for walk/cycle to school. In the adjusted model, higher likelihood of active commuting was found among students who reported having higher self-efficacy (OR=2.10; CI95%: 1.07; 4.11) to walk/cycle to school as well as among adolescents who reported being encouraged by their parents (OR=3.66; CI95%: 1.55; 8.69), and having the partnership of friends in active journeys (OR=4.31; CI95%: 1.79; 10.37).

CONCLUSION

Self-efficacy, encouragement from parents and companionship from friends were important indicators of active commuting to school among Portuguese adolescents. These findings provide support for further research to identify and understand factors that predict and explain the active commuting.

Perceived environmental characteristics and psychosocial factors associated with physical activity levels in adolescents from Northeast Brazil: structural equation modelling analysis

This study aimed to investigate the direct and indirect associations between perceived environmental characteristics and psychosocial factors and physical activity levels in adolescents from Northeast Brazil. The sample was composed of 2,361 adolescents aged 14-19 years (56.6% female). Physical activity was measured using a questionnaire and environmental (perceived environmental characteristics) and psychosocial (self-efficacy, social support from parents and friends for physical activity) factors with previously validated scales. Perceived environmental characteristics were not directly associated with the levels of physical activity, but exhibited significant indirect associations, mediated by self-efficacy in males. Self-efficacy and social support were positively and directly associated with physical activity levels, and part of the associations between social support and physical activity was mediated by self-efficacy. Perception of self-efficacy and social support, important factors associated with physical activity levels in adolescents, should be the target of interventions aimed at increasing physical activity. Favorable environments for physical activity also need to be considered, since they have a positive influence on the self-efficacy of adolescents.

Polymorphisms assessment in the promoter region of IL12RB2 in Amazon leprosy patients

Leprosy displays a wide clinical spectrum that is dependent of the type of immune response. We investigate here whether polymorphisms in the promoter region of the IL12RB2 gene are associated with susceptibility or resistance to clinical forms of leprosy. Nucleotide sequencing of the promoter region of IL12RB2 encompassing SNPs -1035 A/G, -1033 T/C, -1023 A/G, -650 del/G and -464 A/G was performed on DNA samples from 105 leprosy patients and 108 healthy controls. However, none of the SNPs were associated with susceptibility to the disease or any of its clinical forms. Similarly, haplotype analysis did not show any association. The haplotype -1035A/-1033T/-650G/-464A was prevalent, and homozygosity for this haplotype was associated to a lower distribution of CD4(+) T cells (p=0.041). Our data suggest that polymorphisms present in the promoter region of IL12RB2 may not be associated with susceptibility to leprosy or its clinical forms.

Parental physical activity, safety perceptions and children's independent mobility

BACKGROUND

Parents are likely to be a basic influence on their children's behavior. There is an absence of information about the associations between parents' physical activity and perception of neighborhood environment with children's independent mobility.The purpose of this study is to examine the contribution of parental physical activity and perception of neighborhood safety to children's independent mobility.

METHODS

In this cross-sectional study of 354 pupils and their parents, independent mobility, perceptions of neighborhood safety and physical activity were evaluated by questionnaire. Categorical principal components analyses were used to determine the underlying dimensions of both independent mobility and perceptions of neighborhood safety items.

RESULTS

The strongest predictor of independent mobility was the parental perception of sidewalk and street safety (beta = 0.132). Parent's physical activity was also a significant predictor. The final model accounted for 13.0% of the variance.

CONCLUSIONS

Parental perception of neighborhood safety and parents' self reported physical activity might be associated with children's independent mobility. Further research in this topic is needed to explore this possible association.

Is walking to school associated with improved metabolic health?

Background

Active commuting to/from school is an important source of physical activity that has been declining over the past years. Although it is an affordable and simple way of increasing physical activity levels it is still unclear whether it has enough potential to improve health. Therefore, the aim of this cross sectional study was to examine the relationship between active commuting to/from school and metabolic risk factors in 10 to 12 year old children.

Methods

Participants were 229 adolescents, selected through consecutive sampling, (121 girls) with mean age of 11.65 (±0.73) years old from Porto, Portugal. Means of transport to/from school was accessed by asking: ”How do you usually travel to school?” and “How do you usually travel from school?”. Active commuting was considered if children reported at least one of the trips (to or from school) by active means. Total physical activity was obtained with Actigraph accelerometer for 7 consecutive days. Lipid profile measurements were conducted with Cholestech LDX® analyser. Waist circumference and blood pressure were measured by standard methods. The criteria for metabolic syndrome defined by International Diabetes Federation for children and adolescents were used.

Results

Adjusted binary logistic regression analysis suggested that walkers have higher odds to have a better waist circumference (OR = 2.64, 95% CI = 1.63-6.01) and better high density lipoprotein cholesterol (OR = 2.14, 95% CI = 1.01-4.52) profiles than non-active commuters, independent of moderate-to-vigorous physical activity. No associations were found for other metabolic risk factors.

Conclusions

Exertions to increase and maintain walking to school may be particularly relevant as it is likely to have a positive impact on children’s health and eventually decrease metabolic and cardiovascular diseases.

Cardiorespiratory fitness and TV viewing in relation to metabolic risk factors in Portuguese adolescents

BACKGROUND

The purpose of this study was to examine whether adolescents who have high levels of cardiorespiratory fitness (CRF) co-existing with low levels of television (TV) viewing present a better metabolic risk profile compared to their low fit and high TV viewing counterparts.

SUBJECTS AND METHODS

A total of 372 students (aged 12-15 years old) comprised the sample of this study. Anthropometric data (body mass index and waist circumference) was collected. CRF was calculated based upon the 20 metres shuttle run test. A questionnaire was used to estimate weekly TV viewing. Information about biological maturity and parental education was collected. Participants were then categorized into one of four category profiles according to the scores they achieved: low TV-Fit; high TV-Fit; low TV-Unfit and high TV-Unfit. Metabolic risk score (MRS) was calculated based on the sum of the Z-scores of all the metabolic variables analysed.

RESULTS

Logistic regression analyses indicated that the high TV-Unfit group was almost 3-times more likely to be assigned to the high MRS group (OR = 2.85, 95% CI = 1.08-7.50) compared to their low TV-Fit group counterparts.

CONCLUSIONS

The data showed that the high TV-Unfit group was associated with an increased metabolic risk in adolescents after adjustment for gender, age, biological maturity and parental education.

Associations between body mass index, waist circumference and body shape index with resting blood pressure in Portuguese adolescents

BACKGROUND

Elevated blood pressure (BP) in childhood and adolescence is associated with overweight and obesity. Recently a body shape index (ABSI) has been suggested as superior to body mass index (BMI, kg/m(2)) and waist circumference (WC) as a measure of disease risk.

OBJECTIVE

To examine the association between ABSI, BMI, WC and BP in Portuguese adolescents and to consider the role of ABSI, BMI and WC when examining this issue in adolescents.

METHODS AND PROCEDURES

Height, body mass, WC and resting blood pressure were assessed in 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years.

RESULTS

ABSI, BMI and WC were all significantly related to both SBP and DBP (all p = 0.001 or better). ABSI, BMI and WC were all significant predictors of SBP and DBP for the whole sample and when analysed in separate gender groups (p = 0.001 or better in all cases). However, in all cases ABSI was a better predictor of BP than BMI or WC.

CONCLUSIONS

Although BMI and WC significantly predict resting BP in adolescents, the use of ABSI explained a greater amount of the variance in BP in this population. When examining the effect of weight status on BP, researchers should consider use of ABSI alongside BMI.

The association between cardiovascular disease risk and parental educational level in Portuguese children

The aim of this study was to examine any differences in cardiovascular disease (CVD) risk in Portuguese children split by parental educational level. A cross-sectional school-based study was conducted in 2011 on 359 Portuguese children (202 girls and 157 boys) aged 10 to 17 years (mean age ± SD = 13.9 ± 1.98 years). Height and body mass were assessed to determine body mass index (BMI). Parental education level (PEL) was used as a surrogate for socioeconomic status (SES). Capillary blood sampling was used to determine: Total Cholesterol (TC), Triglycerides (TG), Fasting Glucos (GLUC), High and Low Density Lipoprotein (HDL/LDL). These measurements were combined with measures of systolic blood pressure and cardiorespiratory fitness as z-scores. CVD risk was constructed by summing the z-scores. Analysis of covariance, controlling for BMI, indicated that CVD risk was significantly different across PEL groups (p = 0.01), with CVD risk score being significantly lower in low (p = 0.04) and middle (p = 0.008) PEL groups, compared to high PEL. Moreover, the covariate, BMI was also significant (p = 0.0001, β = 0.023), evidencing a significant positive association between BMI and CVD risk, with higher BMI associated with greater CVD risk. In Portuguese children, significantly greater CVD risk was found for children of high PEL, while higher BMI was associated with greater CVD risk.

Differences between weekday and weekend levels of moderate-to-vigorous physical activity in Thai adolescents

Attempts to reduce the decline in physical activity (PA) in adolescence have been the focus of many public health interventions. This study aimed to (1) determine differences in moderate-to-vigorous PA (MVPA) levels between weekdays and weekends and (2) identify adolescents meeting current PA guidelines (PAG). To meet these objectives, 186 Thai adolescents aged 13 to 18 years were asked to wear an ActiGraph accelerometer for 7 consecutive days. The results showed that MVPA levels were significantly higher in boys than girls on both weekdays (P < .01) and weekends (P < .05). MVPA was higher during weekdays compared with weekend days. Additionally, MVPA levels tend to decline with increasing age during adolescence. The results also showed statistically significant differences between genders in the proportion of adherence to PAG for youth. This study highlights the need to take weekend-weekday differences into account when developing PA interventions for adolescents.

[Validity and reproducibility of a physical activity questionnaire for adolescents: adapting the Self-Administered Physical Activity Checklist]

OBJECTIVES

To evaluate test-retest reproducibility and the validity of a physical activity questionnaire for adolescents (adapted from Self-Administered Physical Activity Checklist).

METHODS

The test-retest reproducibility analysis was completed by 239 adolescents (average age 16 years, SD = 1.2; 56.4% female), and the validity analysis by 70 adolescents (average age 15.7 years, SD = 1.2; 55.7% female). All adolescents were high school students in João Pessoa, PB, in Northeastern Brazil, in 2009. The test-retest reproducibility was determined by repeated evaluations with one week interval between them. Validity of the physical activity questionnaire was assessed by comparing the results of the questionnaire with those of four 24-hour recalls (reference method).

RESULTS

The test-retest reproducibility was high (intraclass correlation coefficient: ICC = 0.88; 95%CI: 0.84 - 0.91), and the agreement was moderate for physical activity classified in two groups (< 300 min/week vs. > 300 min/week; kappa coefficient: k = 0.52). Spearman correlation coefficient comparing the questionnaire data with those of four 24-hour recalls (reference method) was moderate (rho = 0.62; p < 0001). The agreement between these measures (questionnaire and 24-hours recalls) for physical activity classified in two groups was moderate (k = 0.59).

CONCLUSIONS

The physical activity questionnaire showed high reproducibility, and moderate validity, and therefore, its use is recommended for assessing adolescents' physical activity level.

Comparisons between inverted body mass index and body mass index as proxies for body fatness and risk factors for metabolic risk and cardiorespiratory fitness in Portuguese adolescents

OBJECTIVES

To compare inverted body mass index (iBMI, cm(2) /kg) and body mass index (BMI, kg/m(2) ) as predictors of body fatness, metabolic risk, and cardiovascular fitness in adolescents.

METHODS

A cross-sectional school-based study was conducted on 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years. Height and body mass were assessed to determine iBMI and BMI, percent body fatness was determined from skinfold measures (tricep, subscapular) using the Slaughter et al. (1988: Hum Biol 60: 709-723) regression equation and cardiorespiratory fitness (CRF) was assessed using the 20-m shuttle run test. Capillary blood sampling was used to determine: Total cholesterol, triglycerides, high, and low density lipoprotein. These were combined with measures of systolic blood pressure and waist circumference as z-scores. Metabolic risk (MRS) was constructed by summing the z-scores.

RESULTS

iBMI and BMI were both significantly related to percent body fatness, CRF and MRS (all P = 0.005 or better). BMI was not normally distributed (P = 0.0001), whereas iBMI was (P > 0.05). Regression analysis identified that iBMI and BMI, both alongside for age, were significant predictors of percent body fatness, CRF and MRS (all P = 0.005 or better). Compared with BMI, iBMI was a similar predictor of CRF, MRS and body fatness.

CONCLUSIONS

iBMI offers a biologically sound alternative to BMI to assess the effect of weight status on MRS and CRF in adolescents and allows appropriate use of parametrical statistical techniques without changing the conclusions drawn from such data.

IFN-γ +875 microsatellite polymorphism as a potential protection marker for leprosy patients from Amazonas state, Brazil

Polymorphisms present in the first intron of IFN-γ may have an important role in the regulation of the immune response, which could have functional consequences for gene transcription. Leprosy patients are characterized by different immune responses in different clinical forms. We investigated a possible association of the +874 polymorphism and CA repeats present in the first intron of IFN-γ with susceptibility to leprosy and with the manifestation of the different clinical forms. Nucleotide sequencing was performed with samples from 108 leprosy patients and 113 controls subjects, as well as immunophenotyping of CD(4)(+), CD(8)(+) and CD(69)(+) T cells by flow cytometry. The data showed that there were no significant differences between patients and control subjects, as well as according classification of Ridley-Jopling. However, the A/A genotype was significantly increased in paucibacillary patients (p=0.028) and the microsatellite encoding 16 CA repeats were significantly associated with paucibacillary compared to multibacillary patients (p=0.019). Individuals homozygous for the +874 A allele, the mean level of CD(4)(+) and CD(69)(+) T cells was higher. Our data suggest that polymorphisms present in the first intron of IFN-γ are not associated with susceptibility to leprosy, nevertheless, the +874 polymorphism and the CA repeats number encoded in IFN-γ gene may be related to a higher cellular immune response in patients and are consistently more frequently detected in PB patients.

A associação entre a proximidade a equipamentos desportivos e a prática de atividade desportiva em adolescentes de 13 anos de idade do Município do Porto, Portugal

O ambiente construído pode influenciar a prática desportiva. O objetivo foi examinar a associação entre a proximidade (500m) de equipamentos desportivos e a participação em atividades desportivas. Foram avaliados 1.175 (54% meninas) estudantes de 13 anos de idade matriculados em escolas públicas e privadas do Município do Porto, Portugal. A atividade desportiva foi avaliada utilizando um questionário autoaplicável. As residências dos participantes e os equipamentos públicos foram georreferenciados. Foi calculada uma matriz de distância da residência de cada participante até os equipamentos. A maioria dos adolescentes (87%) reside na proximidade de, pelo menos, um equipamento desportivo. Não foram encontradas diferenças na prática desportiva relacionadas com a proximidade aos equipamentos (< 500m vs. > 500m), sendo as proporções 44% vs. 38%, p = 0.414 (meninas) e 72% vs. 61%, p = 0.094 (meninos). A proximidade de equipamentos não estava associada com a prática do desporto.

Associations of cardiorespiratory fitness in children and adolescents with physical activity, active commuting to school, and screen time

BACKGROUND

The objective of this study was to analyze associations of cardiorespiratory fitness (CRF) with physical activity, time spent watching television and using computer, mode of commuting to school (CS), and adiposity, by gender.

METHODS

Participants were 1708 students (53.8% girls), aged 11 to 19 years. CRF was evaluated with a 20-meter shuttle-run test using VO2max by previously published equation. Maturation stages determined by Tanner's criteria, body mass index, and skinfolds were measured, and a questionnaire used to assess socioeconomic status, PA, television and computer time, and mode of CS. We conducted a regression analysis using CRF as the dependent variable.

RESULTS

CRF was independent and positively associated with physical activity [β = 0.338 (95% CI = 0.119; 0.188); P < .001] and with maturation [β = -0.876 (95% CI = 0.666; 1.087); P < .001]; independent and negatively associated with television time [β = -0.003 (95% CI = -0.005; -0.002); P < .001] and adiposity [β = -0.068 (95% CI = -0.076; -0.060); P < .001]. CRF was positively associated with CS [β = 0.337; (95% CI = 0.014; 0.741); P = .014]. No associations were found for computer time.

CONCLUSIONS

These findings suggest that increasing overall physical activity levels through interventions in different domains such as active CS, reducing sedentary activities, such as television time, might be effective strategies for improving CRF in youth.

Perception of the social and built environment and physical activity among Northeastern Brazil adolescents

OBJECTIVE

To evaluate the association between levels of physical activity and perception of the social and built environmental in adolescents from Northeastern Brazil.

METHODS

The sample comprised 2874 adolescents aged 14 to 19 years (57.8% females) enrolled in private or public secondary schools in the municipality of João Pessoa, Northeastern Brazil. Level of physical activity was measured by questionnaire. Perception of environmental characteristics was measured by means of fifteen questions rated on four-point Likert-type scales ranging from 1 ("strongly disagree") to 4 ("strongly agree"). The association between physical activity and perception of environmental characteristics was investigated using multivariate binary logistic regression.

RESULTS

Multivariate analysis showed that adolescents living in neighborhoods where other adolescents were physically active (68.7% vs. 60.1%, OR=1.20; 95%CI: 1.05-1.56, among boys only) or who lived close to places they liked to frequent (71.8% vs. 53.4%, OR=1.96; 95%CI: 1.40-2.78 among boys; and 42.0% vs. 32.3% OR=1.33; 95%CI: 1.10-1.74 among girls) were more likely to be physically active.

CONCLUSIONS

Adolescents with positive perceptions of certain environmental characteristics were more likely to be physically active. Environmental characteristics may relate differently to levels of physical activity among boys and girls.

Perceived neighbourhood environmental characteristics and physical activity according to socioeconomic status in adolescent girls

OBJECTIVE

The purpose of this study was to analyse the associations between physical activity (PA) and several characteristics of the built environment with socioeconomic status (SES) in adolescent girls.

METHODS

The sample comprised 599 girls (mean age 14.7, SD = 1.6 years) living in the Aveiro Region of Portugal. Questionnaires were used to describe physical activity level and perceived neighbourhood environments. SES was established by maternal education level. Girls were grouped into low, middle or high SES group.

RESULTS

Logistic regression analysis showed that girls assigned to the higher SES group were more likely (OR = 2.4; 95%CI = 1.3-4.5) to belong to the active group than their low SES peers. Girls in high (OR = 2.4; 95%CC = 1.3-4.4) and medium (OR = 1.6; 95%CC = 1.14-2.3) SES groups were more likely to have a higher perception of better aesthetics in their neighbourhoods than their low SES peers and higher SES was also associated with better perception of a street connectivity (OR = 2.9; 95%CI = 1.7-5.4).

CONCLUSION

The study showed that girls of higher SES are more active than those of lower SES and that social background might be associated with differences in neighbourhood environmental perceptions.

Cardiorespiratory fitness status and body mass index change over time: a 2-year longitudinal study in elementary school children

OBJECTIVE

This study aimed to examine the prospective relationship of baseline body mass index (BMI) and performance in a cardiorespiratory fitness (CRF) field test with a change in BMI (DeltaBMI) over a 2-year period in a sample of rural children from elementary school in Fundão, Portugal.

METHODS

Obesity status was obtained by the age- and sex-specific BMI cut-off points and CRF by a 9-minute run test.

RESULTS

BMI stratification at baseline showed that overweight/obese children were over 11 times (OR=11.31; p=0.007) more likely to be DeltaBMI gainers than their normal weight peers. Those who were classified as unfit were 3.9 times more likely to be DeltaBMI gainers than those classified as fit at baseline. Both BMI at time 1 and CRF change (DeltaCRF) were not significantly associated with DeltaBMI over time.

CONCLUSION

The findings of this study suggest that children who have higher BMI and lower CRF are likely to have greater BMI gain over time.

Obese girls differences in neighbourhood perceptions, screen time and socioeconomic status according to level of physical activity

The purpose of this study was to investigate perceptions of neighbourhood, amount of screen time and socioeconomic status (SES) in active and non-active 'overweight/obese girls'. The sample comprised 162 girls aged 14.1 +/- 1.5 years old. Girls were assigned as active obese (AO) and non-active obese (NAO). Environmental variables, screen time and SES were assessed by questionnaire. No statistically significant differences were found for screen time between AO and NAO groups. Educational status of father (r = 0.23; P = 0.003) and mother (r = 0.18; P = 0.02) was positively and significantly associated with AO. AO girls reported to more significantly (P < 0.05) agree with living in a neighbourhood with several public recreation facilities and that they see people being physically active in neighbourhood. Logistic regression analysis showed that social environment [odds ratio (OR) = 15.06; P = 0.037] and recreational facilities domain (OR = 11.16; P = 0.042) were associated to likelihood to be more active. Creating social support and providing PA facilities within neighbourhoods, particularly in low SES neighbourhoods, are desirable.

Relationships between physical activity, obesity and meal frequency in adolescents

OBJECTIVE

The purpose of this study was to assess the associations and impact of increased meal frequency, physical activity and 'skipping' breakfast on obesity levels in a sample of urban adolescents, aged 13-17 years old, from Porto, Portugal.

METHODS

Overweight and obesity were defined according to age- and sex-specific BMI cut-points. Daily meal frequency was assessed by questionnaire. Self-reported physical activity was recalled.

RESULTS

The proportion of overweight/obese girls (p < or = 0.05) and boys (p < or = 0.001) that consumed fewer than three meals was significantly higher than those reported from normal-weight counterparts. While no statistically significant differences were reported in girls, obese boys skipped breakfast significantly more (13% vs 5.6%; p < or = 0.05) than normal-weight counterparts did. Normal-weight boys but not girls were significantly more active (p < or = 0.01) than obese peers. An additional meal in boys (OR: 2.75; p < or = 0.05) and girls (OR: 1.97; p < or = 0.05) reduced the risk of being overweight/obese. Regardless of gender, breakfast skipping is not seen as a predictor of being overweight/obese. However, boys (OR: 2.10; p < 0.003), but not girls, who were moderately active were more likely to be of normal weight.

CONCLUSION

The data indicate that increased meal frequency may have a beneficial effect on a reduced BMI. Physical activity and breakfast skipping may be candidate targets for prevention programmes aimed at reducing overweight/obesity among adolescents.

["Physical fitness of institutionalized elderly: comparative analysis with reference values"]

In many elders the causes of dependency and institutionalization appear to be simply a progressive loss of functional capacity to undertake the instrumental daily living activities (personal toilet, dressing, etc.). Various professionals thus show considerable interest in the potential to prevent and reverse functional limitations, disability, and dependency by an appropriate regimen of regular PA. The purpose of this study was to characterize the levels of physical performance of 185 institutionalized elders by gender and age, and compare our results with normative standards to determine their functional status. This study reports: (i) men present better physical fitness; (ii) elders present better scores to the standard in the strength and in the aerobic resistance and (iii) worse scores in the flexibility and agility.

Thermodiffusion in a multicomponent lyotropic mixture in the vicinity of the critical micellar concentration by using the Z -scan technique

Thermodiffusion in a lyotropic mixture of water and potassium laurate is investigated by means of an optical technique (Z scan) distinguishing the index variations due to the temperature gradient and the mass gradients. A phenomenological framework allowing for coupled diffusion is developed in order to analyze thermodiffusion in multicomponent systems. An observable parameter relating to the mass gradients is found to exhibit a sharp change around the critical micellar concentration, and thus may be used to detect it. The change in the slope is due to the markedly different values of the Soret coefficients of the surfactant and the micelles. The difference in the Soret coefficients is due to the fact that the micellization process reduces the energy of interaction of the ball of amphiphilic molecules with the solvent.

Active versus passive transportation to school-differences in screen time, socio-economic position and perceived environmental characteristics in adolescent girls

OBJECTIVE

The aims of this study were (1) to assess the relationships between transport to and from school (active vs. passive), sedentary behaviours, measures of socio-economic position and perceived environmental variables, and (2) to determine which, if any, variables were predictors of active transportation.

METHODS

The sample comprised 705 girls with mean age of 14.7 (SD = 1.6) years old. Questionnaires were used to describe travel mode to school and to estimate weekly television and computer use (screen time). Girls were assigned to active transportation (AT) or passive transportation (PT) groups depending on whether they walked or bicycled (AT) to and from school or travelled by car or bus (PT). Screen time was determined by the number of hours they reported watching television and using computers in the week preceding the examination, including weekends. Socio-economic position was established by parental occupation and educational level. A questionnaire assessed Perceived Neighbourhood Environments.

RESULTS

No statistically significant differences were seen for screen time between travel groups. Occupational status of both mother (r = -0.17) and father (r = -0.15) and father's educational level (r = -0.10) were significantly and negatively associated with AT, while street connectivity (r = 0.10) was positively and significantly associated with AT. Logistic regression analysis showed that the likelihood of active commuting decreased by around 50% with increasing father's occupation (odds ratio (OR) = 0.51; p </= 0.05) and father's education (OR = 0.52; p </= 0.05) from low to middle socio-economic position groups. Further, the data showed that girls who agreed that 'there are many four-way intersections in my neighbourhood' were more likely to be active (OR = 1.63; p </= 0.05).

CONCLUSION

The data of this study showed that lower socio-economic position is associated with active commuting to school and that street connectivity is a predictor of active transportation in adolescent girls.

Perceived neighborhood environments and physical activity in an elderly sample

Increasing evidence indicates the importance of environmental variables in explaining physical activity. This study evaluated sex differences in perception of home and neighborhood environmental support and assessed which neighborhood environmental variables were associated with reported physical activity of elderly people. A sample of 126 women (M age = 79.1 +/- 6.6 yr.) and 55 men (M age = 76.6 +/- 7.7 yr.) were healthy, community-dwelling individuals. A questionnaire about environmental variables was administered. Physical activity was assessed on the Baecke Questionnaire. Logistic regression analysis showed that Neighborhood Safety was related to total physical activity, activity in leisure time, and sport activities. Men were also likely to be more active in leisure time than women. Neighborhood Personal Safety was associated with physical activity of these elderly people, showing a potential influence of the environmental domain in physical activity.