A comparative study between traditional and sports school uniforms on cardiorespiratory and muscular fitness and waist-height-to-ratio in adolescents.

Background: Improving health of children and adolescents is crucial for their overall development. Therefore, it is essential to explore factors that may influence their health at both the public health and school system levels. Objective: This study compares physical fitness components and waist-height-to-ratio (WHtR) in adolescents according to school uniforms, namely the traditional uniform (i.e., shirt and school necktie in boys and skirt and blouse in girls) and the sports uniform (i.e., polo shirts or t-shirts and sport or short trousers). Additionally, it seeks to investigate potential differences in these measures based on sex and school type (i.e., public, subsidized, and private). Methods: This cross-sectional study used data from the Chilean national learning outcome assessment system (SIMCE)-2014 and involved 8,030 adolescents. Cardiorespiratory fitness (CRF) and muscular fitness (MF) were measured. WHtR was assessed as a health cardiovascular indicator. Mixed models and ANCOVA were performed to compare uniform types, adjusting for multiple covariates. value of p and effect size (ES) was used to establish significant results. Results: Overall, sports uniforms (SU) were linked to higher CRF (p < 0.001) than the traditional uniform (TU). Boys from private schools wearing SU presented higher CRF (p = 0.016; ES = 0.37), and a positive trend was observed for MF (p = 0.645; ES = 0.21). In subsidized, a trend was found in CRF (p = 0.005; ES = 0.16). Girls wearing SU from private schools showed a positive trend in CRF (p = 0.167; ES = 0.28). Trends in WHtR were found in both sexes from private (p = 0.555; ES = 0.24; p = 0.444; ES = 0.25, respectively). Conclusion: Wearing SU seems a promissory alternative to promote healthy physical fitness and body composition at the educational level. However, the relationship between higher physical activity and CRF, MF, and lower WHtR due to SU must be verified. Finally, when deciding to implement this measure, special attention must be paid to boys from public schools and girls from all types of schools.

Short-term effect of physical activity on sleep health: A population-based study using accelerometry.

BACKGROUND: Regular physical activity (PA) is an important behavior in improving sleep health. However, the short-term effects of PA on sleep are still controversial. This study aimed to verify the effect of different intensities of PA practiced in different periods of the day on the subsequent sleep night in a population-based cohort of young adults. METHODS: Prospective analyses were conducted for PA performed during the day and its effect on the following sleep night using data from the 22-year follow-up of the 1993 Pelotas Birth Cohort in Brazil (mean age of participants = 22.6 years). Wrist-worn accelerometry was used to measure both PA and sleep parameters. Regarding intensity, we analyzed the sleep effect of light PA (LPA), moderate PA, and vigorous PA, stratified by sex. Sleep variables were sleep time window (STW; the difference between sleep onset and sleep end), total sleep time (TST; the sum of minutes classified as sleep in STW), and sleep percent (SP; SP = (TST/STW); expressed in percentage). We performed generalized estimating equations using Stata software. RESULTS: The means of STW, TST, and SP were 443.6 min/day, 371.1 min/day, and 84%, respectively. Time spent in moderate PA and vigorous PA in the morning and afternoon was not associated with sleep variables. Among men, 10 min/day of morning LPA increased TST by 2.56 min/day. Among women, 10 min/day of morning LPA increased SP by 0.15 percentage points. Afternoon LPA also increased SP by 0.09 percentage points for women. Night PA seems to have an inverse effect on sleep variables for any intensity and both sexes. CONCLUSION: The effect of PA on sleep health is intrinsically related to the period of the day in which it is performed. The effect magnitude is different between sexes. For better sleep health, it is preferable that PA be performed during the day.

Physical Activity During Pregnancy and Preterm Birth: Findings From the 2015 Pelotas (Brazil) Birth Cohort Study.

BACKGROUND: Physical activity (PA) during pregnancy is associated with several benefits in maternal and child outcomes, and its relationship with preterm birth is still conflicting. This study aims to examine the associations between PA during pregnancy and occurrence of preterm birth. METHODS: PA was assessed by questionnaire (for each trimester) and accelerometry (second trimester) in women enrolled in a birth cohort study that started during pregnancy and included births that occurred between January 1 and December 31, 2015. Gestational age was based on the last menstrual period and ultrasonography. All deliveries before 37 weeks of gestation were considered preterm births. A Poisson regression model was used to measure associations controlling for potential confounders. RESULTS: PA information was available for 4163 women and 13.8% of births were preterm. A total of 15.8% of women were engaged in PA during pregnancy. Multivariate analysis showed that only PA performed in the third trimester of pregnancy (prevalence ratio = 0.58; 95% confidence interval, 0.36-0.96) was associated with the outcome. CONCLUSIONS: PA performed in the third trimester of pregnancy was associated with a protection to preterm birth. Pregnant women should be counseled to engage in PA to lower the risk of premature delivery.

Wealth-related inequalities in the coverage of reproductive, maternal, newborn and child health interventions in 36 countries in the African Region.

OBJECTIVE: To investigate whether sub-Saharan African countries have succeeded in reducing wealth-related inequalities in the coverage of reproductive, maternal, newborn and child health interventions. METHODS: We analysed survey data from 36 countries, grouped into Central, East, Southern and West Africa subregions, in which at least two surveys had been conducted since 1995. We calculated the composite coverage index, a function of essential maternal and child health intervention parameters. We adopted the wealth index, divided into quintiles from poorest to wealthiest, to investigate wealth-related inequalities in coverage. We quantified trends with time by calculating average annual change in index using a least-squares weighted regression. We calculated population attributable risk to measure the contribution of wealth to the coverage index. FINDINGS: We noted large differences between the four regions, with a median composite coverage index ranging from 50.8% for West Africa to 75.3% for Southern Africa. Wealth-related inequalities were prevalent in all subregions, and were highest for West Africa and lowest for Southern Africa. Absolute income was not a predictor of coverage, as we observed a higher coverage in Southern (around 70%) compared with Central and West (around 40%) subregions for the same income. Wealth-related inequalities in coverage were reduced by the greatest amount in Southern Africa, and we found no evidence of inequality reduction in Central Africa. CONCLUSION: Our data show that most countries in sub-Saharan Africa have succeeded in reducing wealth-related inequalities in the coverage of essential health services, even in the presence of conflict, economic hardship or political instability.

Does women's age matter in the SDGs era: coverage of demand for family planning satisfied with modern methods and institutional delivery in 91 low- and middle-income countries.

BACKGROUND: The Sustainable Development Goals (SDGs) include specific targets for family planning (SDG 3.7) and birth attendance (SDG 3.1.2), and require analyses disaggregated by age and other dimensions of inequality (SDG 17.18). We aimed to describe coverage with demand for family planning satisfied with modern methods (DFPSm) and institutional delivery in low- and middle-income countries across the reproductive age spectrum. We attempted to identify a typology of patterns of coverage by age and compare their distribution according to geographic regions, World Bank income groups and intervention coverage levels. METHODS: We used Demographic and Health Survey and Multiple Indicator Cluster Surveys. For DFPSm, we considered the woman's age at the time of the survey, whereas for institutional delivery we considered the woman's age at birth of the child. Both age variables were categorized into seven groups of 5 year-intervals, 15-19 up to 45-49. Five distinct patterns were identified: (a) increasing coverage with age; (b) similar coverage in all age groups; (c) U-shaped; (d) inverse U-shaped; and (e) declining coverage with age. The frequency of the five patterns was examined according to UNICEF regions, World Bank income groups, and coverage at national level of the given indicator. RESULTS: We analyzed 91 countries. For DFPSm, the most frequent age patterns were inverse U-shaped (53%, 47 countries) and increasing coverage with age (41%, 36 countries). Inverse-U shaped patterns for DFPSm was the commonest pattern among lower-middle income countries, while low- and upper middle-income countries showed a more balanced distribution between increasing with age and U-shaped patterns. In the first and second tertiles of national coverage of DFPSm, inverse U-shaped was observed in more than half of countries. For institutional delivery, declining coverage with age was the prevailing pattern (44%, 39 countries), followed by similar coverage across age groups (39%, 35 countries). Most (79%) upper-middle income countries showed no variation by age group while most low-income countries showed declining coverage with age (71%). CONCLUSION: Large inequalities in DFPSm and institutional delivery were identified by age, varying from one intervention to the other. Policy and programmatic approaches must be tailored to national patterns, and in most cases older women and adolescents will require special attention due to lower coverage and because they are at higher risk for maternal mortality and other poor obstetrical outcomes.

Prenatal and birth predictors of objectively measured physical activity and sedentary time in three population-based birth cohorts in Brazil.

Physical inactivity is a global pandemic with no signs of improvement. Prolonged sitting time is an emerging risk factor that exacerbates the health consequences of physical inactivity. Both behaviours are influenced by various individual and environmental factors but it remains unknown whether early-life exposures "program" these behaviours in later life. The current evidence is limited by a small number of studies which were primarily conducted in high-income countries, and a narrow range of early-life variables examined. Using data from three population-based Brazilian birth cohorts (analytical samples: n = 2740 for 1982 cohort, aged 30 years; n = 3592 for 1993 cohort, aged 18; n = 2603 for 2004 cohort, aged 6), we show that being female and higher family socioeconomic status at birth are strong and consistent predictors of lower physical activity and higher sedentary time from childhood to adulthood. Meanwhile, higher birth weight and lower birth order may also predict lower physical activity and higher sedentary time. Our findings are distinct from evidence from high-income countries, suggesting the importance of broader socioeconomic context in determining individual's activity patterns through the life- course. Such evidence is essential for understanding the biological etiology and socioeconomic context of physical activity and sedentary behaviour at an early stage in life.

Objectively measured physical activity in one-year-old children from a Brazilian cohort: levels, patterns and determinants.

BACKGROUND: The aim of this study is to describe objectively measured physical activity (PA) and its correlates in one-year-old children. METHODS: The current study includes participants from the 2015 Pelotas (Brazil) birth cohort. At age one, PA was assessed in a 24-h protocol during 4 days with a wrist-attached accelerometer (ActiGraph, wGT3X-BT), from which two complete days of data were analyzed, with 5-s epochs. RESULTS: A total of 2974 individuals provided valid accelerometry data. Infants able to walk independently spent on average 19 h per day below 50 mg of acceleration (including sleep time), and those who could not walk spent on average 21 h in this intensity category. Girls spent approximately 10 min more than boys below 50 mg daily in both walking status categories, and less activity than boys on higher intensity categories. Boys and infants whose mothers were more physically active during pregnancy presented more acceleration, regardless of walking status. Among infants who could walk by themselves, those with mothers with one to eight schooling years; adequate length-for-age (z-score); not attending daycare; and more physically active fathers also showed higher levels of acceleration. CONCLUSIONS: Our findings demonstrate higher levels of PA among boys and those children with higher maternal PA during pregnancy, regardless of walking status. Also, among infants able to independently walk, 1-8 years of maternal schooling, adequate length-for-age (z-score), no daycare attendance and higher paternal PA are positive correlates of objectively measured PA early in life.

Associations of physical activity and sedentary time with body composition in Brazilian young adults.

The findings of studies on the association between physical activity and adiposity are not consistent, and most are cross-sectional and used only self-reported measures. The aims of this study were to evaluate: 1) independent and combined cross-sectional associations of objectively-measured physical activity and sedentary time with body composition outcomes at 30 years, and 2) prospective associations of changes in self-reported physical activity from 23 to 30 years with the same outcomes in participants from the 1982 Pelotas (Brazil) Birth Cohort. Body mass index, waist circumference, visceral abdominal fat, fat mass index, and android/gynoid fat ratio were the outcomes. 3,206 participants were analysed. In cross-sectional analyses, higher objectively-measured moderate-to-vigorous physical activity was associated with lower body mass index (ß = 0.017, 95%CI: -0.026; -0.009), waist circumference (ß = -0.043, 95%CI: -0.061; -0.025), visceral abdominal fat (ß = -0.006, 95%CI: -0.009; -0.003), and fat mass index (ß = -0.015, 95%CI: -0.021; -0.009), independent of sedentary time. Sedentary time was independently associated only with higher fat mass index (ß = 0.003, 95%CI: 0.001; 0.005). In longitudinal analyses, using self-reported measure, adiposity was lower among those who were consistently active or who became active. Adiposity was similar among the "became inactive" and "consistently inactive" subjects. Our findings suggest metabolic benefits from engagement in physical activity throughout young adulthood, with stronger associations on concurrent levels.

Association of physical activity with sleep health: a systematic review / Associação da atividade física com o sono: uma revisão sistemática

The aim of this study was to systematically examine the literature on physical activity and sleep in non-clinical and population-based settings. The inclusion criteria were original studies testing the association between physical activity (as exposure) and sleep (as outcome) in representative samples of the general population, workers, or undergraduate students. Sleep health included sleep duration, sleep quality and insomnia. Studies evaluating samples including only individuals with some dis-ease or a health condition were excluded. A search was performed in the PubMed, Scopus, Lilacs, CINAHL, and SPORTdiscus databases in March 2018. Data extraction was performed using the following items: year, author, country, population, age group, sample size, study design, sleep meas-urement/definition, physical activity measurement/definition, adjustment and main results. A total of 57 studies were selected, which markedly used heterogeneous instruments to measure physical activity and sleep. The majority were conducted in high-income countries and with cross-sectional design. Physical activity was associated with lower odds of insomnia (observed in 10 of 17 studies), poor sleep quality (observed in 12 of 19 studies) and long sleep duration (observed in 7 of 11 studies). The results about short sleep or continuous sleep duration remain unclear. Physical activity seems to be associated with sleep quality and insomnia, especially among adult and elderly populations in which these outcomes are more usually measured. The short- and long-term effects of physical activity intensities and dose-response on sleep should be better evaluated

Examinar sistematicamente a literatura sobre atividade física e sono em amostras não clínicas e de base populacional. Foram incluídos artigos originais testando a associação entre atividade física (como exposição) e sono (como desfecho) em amostras representativas da população em geral, de trabalhadores ou de univer-sitários. Os desfechos incluídos foram duração do sono, qualidade do sono e insônia. Estudos que avaliaram amostras que incluíram somente indivíduos com alguma doença ou condição de saúde foram excluídos. A busca foi realizada em março de 2018 nas seguintes bases: PubMed, Scopus, Lilacs, CINAHL e SPORTdis-cus. As informações extraídas dos dados foram ano, autor, país, população, faixa etária, tamanho da amostra, delineamento, mensuração e definição das variáveis de desfecho e exposição, variáveis de ajuste e principais resultados. Foram selecionados 57 estudos. A maioria foi conduzida em países de renda alta e com delinea-mento tranversal. Atividade física foi associada a menor odds de insônia (10 de 17 estudos), qualidade ruim do sono (12 de 19 estudos) e longa duração (7 de 11 estudos). Os resultados sobre curta duração ou duração avaliada de forma contínua permanecem inconclusivos. Os estudos selecionados usaram instrumentos hete-rogêneos tanto para atividade física quanto sono. Atividade física parece estar associada com qualidade do sono e insônia especialmente entre adultos e idosos onde estes desfechos foram mais frequentemente avaliados. Os efeitos a curto e longo prazo da atividade física em diferentes intensidades ainda precisam ser melhor explorados em futuros estudos originais

Physical activity during pregnancy and offspring neurodevelopment: A systematic review.

BACKGROUND: Maternal physical activity (PA) during pregnancy could affect offspring's neurodevelopment. However, studies in humans in early childhood are scarce and show inconsistent results. We aimed to review the literature on the association between physical activity during pregnancy and offspring neurodevelopment. METHODS: LILACS, MEDLINE and Web of Science were searched for studies published since 1977. Original studies conducted in humans, without language, country, or study type restriction, were eligible. Information on the study methodology like study design, sample size, PA exposure and neurodevelopment assessment, covariates, and the effect measure were extracted from the selected articles. RESULTS: From 802 non-duplicated titles initially located, 6 articles were selected and included (one randomised clinical trial and 5 cohort studies). The instruments used to measure PA during pregnancy and neurodevelopment varied between the studies. PA was self-reported at different gestational ages and neurodevelopment was assessed prospectively in offspring aged 1-8 years old. Only the randomised clinical trial found no effect of PA over offspring neurodevelopment. Cohort studies found a positive association between PA practice during pregnancy and offspring neurodevelopment. CONCLUSIONS: These findings suggest that leisure-time physical activity practice may have positive association with language offspring's neurodevelopment in the age range of 18 from 60 months.

Effect of physical exercise on spontaneous physical activity energy expenditure and energy intake in overweight adults (the EFECT study): a study protocol for a randomized controlled trial.

BACKGROUND: Physical exercise interventions have been extensively advocated for the treatment of obesity; however, clinical trials evaluating the effectiveness of exercise interventions on weight control show controversial results. Compensatory mechanisms through a decrease in energy expenditure and/or an increase in caloric consumption is a possible explanation. Several physiological mechanisms involved in the energy balance could explain compensatory mechanisms, but the influences of physical exercise on these adjustments are still unclear. Therefore, the present trial aims to evaluate the effects of exercise on non-exercise physical activity energy expenditure, energy intake and appetite sensations among active overweight/obese adults, as well as, to investigate hormonal changes associated with physical exercise. METHODS: This study is a randomized controlled trial with parallel, three-group experimental arms. Eighty-one overweight/obese adults will be randomly allocated (1:1:1 ratio) to a vigorous exercise group, moderate exercise group or control group. The trial will be conducted at a military institution and the intervention groups will be submitted to exercise sessions in the evening, three times a week for 65 min, during a 2-week period. The primary outcome will be total spontaneous physical activity energy expenditure during a 2-week period. Secondary outcomes will be caloric intake, appetite sensations and laboratorial biomarkers. Intention-to-treat analysis will be performed using linear mixed-effects models to evaluate the effect of treatment-by-time interaction on primary and secondary outcomes. Data analysis will be performed using SAS 9.3 and statistical significance will be set at p < 0.05. DISCUSSION: The results of the present study will help to understand the effect of physical exercise training on subsequent non-exercise physical activity, appetite and energy intake as well as understand the physiological mechanisms underlying a possible compensatory phenomenon, supporting the development of more effective interventions for prevention and treatment of obesity. TRIAL REGISTRATION: Physical Exercise and Energy Balance trial registry, trial registration number: NCT 03138187 . Registered on 30 April 2017.

Socioeconomic Inequalities Persist Despite Declining Stunting Prevalence in Low- and Middle-Income Countries.

Background: Global stunting prevalence has been nearly halved between 1990 and 2016, but it remains unclear whether this decline has benefited poor and rural populations within low- and middle-income countries (LMICs). Objective: We assessed time trends in stunting among children <5 y of age (under-5) according to household wealth and place of residence in 67 LMICs. Methods: Stunting prevalence was analyzed in 217 nationally representative Demographic and Health Surveys and Multiple Indicator Cluster Surveys from 67 countries with ≥2 surveys between 1993 and 2014. National estimates were stratified by wealth and area of residence, comparing the poorest 40% with the wealthiest 60%, and those residing in urban and rural areas. Time trends were calculated for LMICs by using multilevel regression models weighted by under-5 population, with stratification by wealth and by residence. Trends in absolute (slope index of inequality; SII) and relative (concentration index; CIX) inequalities were calculated. Results: Mean prevalences in 1993 were 53.7% in low-income and 48.2% in middle-income countries, with annual average linear declines of 0.76 and 0.72 percentage points (pp), respectively. Although similar slopes of declines were observed for the poorest 40% and wealthiest 60% groups in all countries (0.78 and 0.74 pp, respectively), absolute and relative inequalities increased over time in low-income countries (SII increased from -19.3% in 1993 to -23.7% in 2014 and CIX increased from -6.2% to -10.8% in the same period). In middle-income countries, socioeconomic inequalities remained stable. Overall, stunting prevalence decreased more rapidly among rural than for urban children (0.78 and 0.55 pp, respectively). Conclusions: The prevalence of stunting is decreasing. Poor-rich gaps are stable in middle-income countries and slightly increasing in low-income countries. Rural-urban inequalities are decreasing over time.

Overall and Leisure-Time Physical Activity Among Brazilian Adults: National Survey Based on the Global Physical Activity Questionnaire.

BACKGROUND: To describe overall physical activity prevalence measured by the Global Physical Activity Questionnaire as well as inequalities in leisure-time physical activity among Brazilian adults (15 y and older). METHODS: Data from the Brazilian Survey on Medicine Access, Utilization, and Rational Use of Medicines were analyzed. The study was carried out between September 2013 and February 2014. Physical activity was measured through Global Physical Activity Questionnaire and classified according to the recommendations of the World Health Organization. Additional analysis determined the contribution of each physical activity domain to the total amount of physical activity. Inequalities in terms of sex, age, and socioeconomic position were explored. RESULTS: About one-third of the participants (37.1%; 95% confidence interval, 35.5-38.8) were physically inactive. Work-based activities were responsible for 75.7% of the overall physical activity. The prevalence of participants achieving physical activity guidelines considering only leisure-time activities was 17.8% (95% confidence interval, 16.7-19.2). Females and older participants were less active than their counterparts for both overall and leisure-time physical activity; socioeconomic status was positively associated to leisure-time physical activity. CONCLUSIONS: Major overall physical activity is attributed to work-related physical activity. Leisure-time physical activity, a key domain for public health, presents important gender and socioeconomic inequalities.

Shifting the Physical Inactivity Curve Worldwide by Closing the Gender Gap.

PURPOSE: The aims of this study were to (i) examine gender differences in physical inactivity in countries with different levels of Human Development Index (HDI); and (ii) assess whether small changes in the prevalence of inactivity in women could achieve the World Health Organization's (WHO) global inactivity target. METHODS: Data on inactivity were extracted for 142 countries for the year 2010 from the WHO Data Repository. Data for HDI were obtained for the year 2010 from the United Nations Development Program. Absolute and relative gender differences were calculated for countries according to four HDI categories. The potential effects of increasing women's activity levels on achievement of the WHO physical inactivity target were computed. RESULTS: Overall inactivity prevalence was higher in women (27%) than in men (20%). Women were more inactive than men in all except eight countries. Absolute gender differences [median 7.5% (range -10.1 to 33.2)] did not vary by HDI category, but there was a small negative correlation between relative gender difference in inactivity and HDI (rho -0.19; p = 0.02), which was mostly influenced by three outlier countries with low HDI. A decrease in inactivity levels of 4.8% points among women across the world would achieve the WHO target of reducing global levels of inactivity by 10%. CONCLUSION: Gender differences in the prevalence of physical inactivity were highly variable, both within and across categories of HDI. Interventions which result in small changes in inactivity prevalence in women would achieve the 2025 WHO global target for inactivity, without any change to the prevalence in men.

Is governance, gross domestic product, inequality, population size or country surface area associated with coverage and equity of health interventions? Ecological analyses of cross-sectional surveys from 80 countries.

OBJECTIVE: To assess associations between national characteristics, including governance indicators, with a proxy for universal health coverage in reproductive, maternal, newborn and child health (RMNCH). DESIGN: Ecological analysis based on data from national standardised cross-sectional surveys. SETTING: Low-income and middle-income countries with a Demographic and Health Survey or a Multiple Indicator Cluster Survey since 2005. PARTICIPANTS: 1 246 710 mothers and 2 129 212 children from 80 national surveys. EXPOSURES OF INTEREST: Gross domestic product (GDP), country surface area, population, Gini index and six governance indicators (control of corruption, political stability and absence of violence, government effectiveness, regulatory quality, rule of law, and voice and accountability). MAIN OUTCOMES: Levels and inequality in the composite coverage index (CCI), a weighted average of eight RMNCH interventions. Relative and absolute inequalities were measured through the concentration index (CIX) and slope index of inequality (SII) for CCI, respectively. RESULTS: The average values of CCI (70.5% (SD=13.3)), CIX (5.3 (SD=5.1)) and mean slope index (19.8 (SD=14.7)) were calculated. In the unadjusted analysis, all governance variables and GDP were positively associated with the CCI and negatively with inequalities. Country surface showed inverse associations with both inequality indices. After adjustment, among the governance indicators, only political stability and absence of violence was directly related to CCI (ß=6.3; 95% CI 3.6 to 9.1; p<0.001) and inversely associated with relative (CIX; ß=-1.4; 95% CI -2.4 to -0.4; p=0.007) and absolute (SII; ß=-5.3; 95% CI -8.9 to -1.7; p=0.005) inequalities. The strongest associations with governance indicators were found in the poorest wealth quintile. Similar patterns were observed for GDP. Country surface area was inversely related to inequalities on CCI. CONCLUSIONS: Levels and equity in RMNCH interventions are positively associated with political stability and absence of violence, and with GDP, and inversely associated with country surface area.

Objectively-measured physical activity in children is influenced by social indicators rather than biological lifecourse factors: Evidence from a Brazilian cohort.

The aim of this study was to examine the longitudinal influences of early life social and biological indicators on objectively measured physical activity. All newborns in 2004 in the city of Pelotas, Southern Brazil were enrolled in a birth cohort study. At the age of 6years, a follow-up visit included objective assessment of overall physical activity (summarized in milli-g, 1mg=0.001g) by tri-axial wrist worn accelerometry. The associations between early life exposures, such as type of delivery, parity, birth weight, preterm delivery, maternal physical activity, socioeconomic position, and overall physical activity were examined. Valid accelerometry data were obtained from 2604 children (78.2% of the eligible individuals). Girls were less active than boys (ß=-8.65mg; 95% CI -10.0; -7.30). Higher socioeconomic position was related to lower activity levels (ß=-9.69mg. 95% CI -12.45; -6.93) and a similar association was found with maternal schooling. No associations were found with birthweight, type of delivery or preterm delivery. This study provides evidence for the role of some social factors in explaining children's physical activity behaviors, and minimizes the influence of some early life biological factors at determining physical activity levels.