Virgílio Viana Ramires

Physical activity levels in three Brazilian birth cohorts as assessed with raw triaxial wrist accelerometry

Background: Data on objectively measured physical activity are lacking in low- and middle-income countries. The aim of this study was to describe objectively measured overall physical activity and time spent in moderate-to-vigorous physical activity (MVPA) in individuals from the Pelotas (Brazil) birth cohorts, according to weight status, socioeconomic status (SES) and sex. Methods: All children born in 1982, 1993 and 2004 in hospitals in the city of Pelotas, Brazil, constitute the sampling frame; of these 99% agreed to participate. The most recent follow-ups were conducted between 2010 and 2013. In total, 8974 individuals provided valid data derived from raw triaxial wrist accelerometry. The average acceleration is presented in milli-g (1 mg = 0.001g), and time (min/d) spent in MVPA (>100 mg) is presented in 5- and 10-min bouts. Results: Mean acceleration in the 1982 (mean age 30.2 years), 1993 (mean age 18.4 years) and 2004 (mean age 6.7 years) cohorts was 35 mg, 39 mg and 60 mg, respectively. Time spent in MVPA was 26 [95% confidence interval (CI) 25; 27], 43 (95% CI 42; 44) and 45 (95% CI 43; 46) min/d in the three cohorts, respectively, using 10-min bouts. Mean MVPA was on average 42% higher when using 5-min bouts. Males were more active than females and physical activity was inversely associated with age of the cohort and SES. Normal-weight individuals were more active than underweight, overweight and obese participants. Conclusions: Overall physical activity and time spent in MVPA differed by cohort (age), sex, weight status and SES. Higher levels of activity in low SES groups may be explained by incidental physical activity.

Methodological description of accelerometry for measuring physical activity in the 1993 and 2004 Pelotas (Brazil) birth cohorts

The aim of this study was to characterize the methodology of data collection on physical activity using accelerometry in two birth cohorts (2004 and 1993) in Pelotas, Rio Grande do Sul State, Brazil, at the 6-7 and 18-year follow-up visits, respectively. During visits to the study headquarters for a health evaluation, cohort subjects received the accelerometer to be worn on the wrist for 5 to 8 days, after which the device was retrieved at their homes. Genea and GENEActiv triaxial estimators of gravity (g) acceleration were employed. Accelerometry data were collected from 3,331 children (93.7% of those included in follow-up) and 3,816 adolescents (99% of those in follow-up). The study characterizes the data collection methodology in more than 7,000 individuals and discusses issues in its implementation. It thus provides a methodological framework aimed at helping to plan future population-based studies with the use of such technology and to improve understanding of physical activity in the context of epidemiological studies.

Social Support and Leisure-Time Physical Activity Among the Elderly: A Population-Based Study

BACKGROUND Physical inactivity in elderly is a public health problem. The purpose of this study is to describe and test the association between social support and leisure-time physical activity among the elderly. METHODS A cross-sectional, population-based study with 1,285 subjects (60+ years old) living in a city in southern Brazil was carried out in 2014. Physical activity practice was measured using the International Physical Activity Questionnaire [leisure domain: at least 150 minutes per week of walking + moderate physical activity + 2(vigorous physical activity)], while social support was measured using the Physical Activity Social Support Scale. RESULTS The prevalence of elderly who reached the recommendations of leisure-time physical activity was 18.4%. The elderly persons who had the company of family or friends to walk had a 2.45 times higher prevalence of reaching the recommendations of physical activity in leisure than those who did not. Those who had company of friends to practice moderate-to-vigorous physical activity (MVPA) were 3.23 times more likely to reach physical activity recommendations than their counterparts. The least common social support was the joint practice for walking and for MVPA. CONCLUSION Strategies that incentivize family members and friends to provide social support to the elderly for physical activity focusing on joint practice must be encouraged.

Descrição metodológica do uso de acelerometria para mensurar a prática de atividade física nas coortes de nascimentos de Pelotas, Rio Grande do Sul, Brasil, 1993 e 2004

O objetivo deste trabalho e caracterizar a metodologia de coleta de atividade fisica por meio de acelerometria nas coortes de nascidos em 2004 e 1993 em Pelotas, Rio Grande do Sul, Brasil, nos acompanhamentos dos 6-7 e 18 anos, respectivamente. Ao visitarem a sede para um amplo estudo de saude, esses individuos receberam o acelerometro e a posterior busca foi realizada no domicilio por meio de motociclistas da equipe de pesquisa. Os modelos utilizados foram o GENEA e GENEActiv, estimadores triaxiais da aceleracao da gravidade (g), utilizados no punho de criancas e adolescentes por um periodo de 5 a 8 dias. O numero de individuos com dados de acelerometria nas coortes foi de 3.331 criancas (93,7% do acompanhamento) e 3.816 jovens (92,9% do acompanhamento). Ao caracterizarmos a coleta de acelerometria em mais de 7.000 individuos, apresenta-se um arcabouco metodologico para o planejamento de novos estudos populacionais no tema, descrevendo situacoes especificas dessa experiencia e qualificando a compreensao da atividade fisica no contexto de estudos epidemiologicos.

Longitudinal Association Between Physical Activity and Body Fat During Adolescence: A Systematic Review

BACKGROUND Physical activity (PA) practice has been inversely associated to body fat (BF) and recommended as a way to reduce and prevent obesity. The objective of this study was to conduct a systematic review on the association of PA and BF in adolescence. METHODS The review includes 18 longitudinal studies found in the PubMed database, comprising papers published from January 1990 to July 2014. Studies assessing BF only through body mass index were excluded. RESULTS Among the outcomes analyzed, waist circumference, skinfolds, and absolute and relative fat mass measurement were identified. Questionnaires were the more predominant way to evaluate PA. Most studies showed that PA promotes a protective effect against a higher BF gain. CONCLUSION It was concluded that PA has a protective effect against BF with differences between the genders and according to the BF marker or measurement assessed; higher intensity PA leads to a greater effect against BF gain in both genders; and the maintenance or increase of PA level on BF observed through analysis of change in PA level yielded more consistent findings in the relation between PA and BF.

Calibration of raw accelerometer data to measure physical activity: A systematic review

Most of calibration studies based on accelerometry were developed using count-based analyses. In contrast, calibration studies based on raw acceleration signals are relatively recent and their evidences are incipient. The aim of the current study was to systematically review the literature in order to summarize methodological characteristics and results from raw data calibration studies. The review was conducted up to May 2017 using four databases: PubMed, Scopus, SPORTDiscus and Web of Science. Methodological quality of the included studies was evaluated using the Landis and Kochs guidelines. Initially, 1669 titles were identified and, after assessing titles, abstracts and full-articles, 20 studies were included. All studies were conducted in high-income countries, most of them with relatively small samples and specific population groups. Physical activity protocols were different among studies and the indirect calorimetry was the criterion measure mostly used. High mean values of sensitivity, specificity and accuracy from the intensity thresholds of cut-point-based studies were observed (93.7%, 91.9% and 95.8%, respectively). The most frequent statistical approach applied was machine learning-based modelling, in which the mean coefficient of determination was 0.70 to predict physical activity energy expenditure. Regarding the recognition of physical activity types, the mean values of accuracy for sedentary, household and locomotive activities were 82.9%, 55.4% and 89.7%, respectively. In conclusion, considering the construct of physical activity that each approach assesses, linear regression, machine-learning and cut-point-based approaches presented promising validity parameters.

Physical Activity at 11 Years of Age and Incidence of Mental Health Problems in Adolescence: Prospective Study

AIM To evaluate the longitudinal association between physical activity behavior at 11 years of age and the incidence of mental health problems from 11 to 15 years of age. METHODS Individuals born in the city of Pelotas, Brazil, in 1993 have been followed up since birth. At 11 and 15 years of age, mental health was assessed using the Strengths and Difficulties Questionnaire (SDQ). At 11 years of age, physical activity was assessed through a validated questionnaire. The continuous SDQ score at 15 years was used as the outcome variable. The main exposure was physical activity behavior at 11 years of age divided into 3 categories (0, 1-299, ≥ 300 min/wk). RESULTS The incidence of mental health problems from 11 to 15 years was 13.6% (95% CI, 12.4-14.9). At 11 years, 35.2% of the adolescents achieved 300 min/wk of physical activity. In the unadjusted analysis, physical activity was inversely related to mental health problems (P = .04). After adjustment for confounders, the association was no longer significant in the whole sample but was still significant among boys. CONCLUSION Physical activity appears to be inversely related to mental health problems in adolescence, but the magnitude of the association is weak to moderate.

Longitudinal and Cross-Sectional Associations of Physical Activity With Triglyceride and HDLc Levels in Young Male Adults

BACKGROUND The purpose of this study was to evaluate cross-sectional and longitudinal associations between physical activity and triglyceride and HDLc levels in young male adults. METHODS We used information about males belonging 1982 Pelotas Birth Cohort. Physical activity in 4 domains (leisure time, transportation, household, and occupation) was assessed by self-report in participants of the cohort at ages of 18 and 23 years. Subjects were active if reached the recommendation of 150 min/week of moderate to vigorous physical activity. At 23 years of age, blood sample was collected, and triglycerides and HDLc levels estimated. Multivariate linear and Poisson regression were used to adjust the estimates for confounders. RESULTS Males who were inactive at 18 and active at 23 years had 41% lower risk (β = 0.59; 95% confidence interval: 0.40; 0.89) for borderline-high triglycerides (≥ 150 mg/dL) as compared with those who were inactive at both follow-ups. No association was found between changes of physical activity and HDLc level. In cross-sectional analyses, greater HDLc levels were found in active subjects in 4 domains, whereas there was no difference in HDL levels according physical activity during leisure time. CONCLUSION Becoming active from adolescence to early adulthood reduced the risk for high triglycerides. Current physical activity was associated with greater HDLc levels.

Metabolic equivalent of task (METs) thresholds as an indicator of physical activity intensity

The purpose of the study was to identify and compare validity parameters of different absolute intensity thresholds in METs, using relative intensity classification as criterion measure. Convenience sampling was used to recruit total of 112 adults. The participants carried out an incremental maximal cycle ergometer test and asked to perform nine free-living activities. The oxygen uptake was measured by a VO2000® gas analyser throughout the tests. The intensity thresholds were identified using Receiver Operator Characteristic (ROC) curve analysis, having relative intensity categories as criterion measure. A total of 103 participants attended the two visits. Among 54 men and 49 women, the mean (± SD) ages were 36.1 (± 11.1) and 33.9 (± 10.6) years, respectively. The intensity thresholds identified were 4.9 METs for moderate and 6.8 METs for vigorous physical activity. In conclusion, the physical activity thresholds, generated according to the entire sample, were higher and presented improved specificity when compared to thresholds currently recommended. Moreover, these parameters presented relatively high accuracy, even when applied to specific groups such as sex, age, nutritional status and physical fitness.

Simultaneity of risk factors for chronic non-communicable diseases in the elderly in Pelotas, Rio Grande do Sul State, Brazil[Simultaneidade de fatores de risco para doenças crônicas não transmissíveis entre idosos da zona urbana de Pelotas, Rio Grande do Sul, Brasil]

Resumo: O objetivo do estudo foi descrever a simultaneidade de fatores de risco para doencas cronicas nao transmissiveis em idosos (60 anos ou mais), residentes em uma cidade do Sul do Brasil. Trata-se de um estudo transversal, de base populacional, realizado em 1.451 idosos em 2013. Com uma abordagem de analise de clusters, foi avaliado o agrupamento entre os fatores de risco em estudo (tabagismo, consumo de alcool, excesso de peso e inatividade fisica). Para a avaliacao da associacao da simultaneidade dos fatores de risco com variaveis sociodemograficas, foi utilizada regressao logistica. O agrupamento mais frequente entre os homens (18,1%) e mulheres (30,7%) foi inatividade fisica + excesso de peso. As combinacoes consumo de alcool + excesso de peso excederam o esperado entre os homens (O/E = 1,27; IC95%: 1,01; 1,59) e mulheres (O/E = 1,72; IC95%: 1,35; 2,20). A presenca de dois ou mais fatores de risco na populacao idosa (88,1%) aponta para a necessidade de intervencoes especificas para esta populacao voltadas ao combate simultâneo dos fatores de risco e nao de forma isolada.This study aimed to describe the simultaneity of risk factors for chronic non-communicable diseases among the elderly (≤ 60 years) in a city in Southern Brazil. This was a cross-sectional, population-based study of 1,451 elderly in 2013. Cluster analysis was applied to selected risk factors (smoking, alcohol consumption, excess weight, and physical inactivity). Logistic regression was used to assess the association between simultaneity of risk factors and socio-demographic variables. The most frequent cluster in men (18.1%) and women (30.7%) was physical inactivity + excess weight. The cluster alcohol consumption + excess weight exceeded the expected level in men (O/E = 1.27; 95%CI: 1.01; 1.59) and women (O/E = 1.72; 95%CI: 1.35; 2.20). The presence of two or more risk factors in the elderly population (88.1%) points to the need for specific interventions for this population to fight risk factors simultaneously rather than separately.