Background: This investigation aimed to analyze the agreement between the GT3X accelerometer and the ActivPAL inclinometer for estimating and detecting changes in sedentary behavior of different contexts among adolescents. Methods: Secondary data from an intervention using standing desks in the classroom conducted within 2 sixth-grade classes (intervention [n = 22] and control [n = 27]) were used. The intervention took place over 16 weeks, with activity assessments (ActivPAL and GT3X) being performed 7 days before and in the last week of the intervention. Baseline information from both groups was considered for cross-sectional analysis (209 valid days), while data from 20 participants (intervention group) were used for longitudinal analysis. Results: The authors observed that GT3X overestimated sedentary time at school (16.8%), after school (13.5%), and during weekends (7.3%) compared with ActivPAL (P < .05). Outside the school (after school [r = −.188] and on weekends [r = −.260]), there was a trend to higher overestimation among adolescents with less sedentary behavior. Longitudinally, the GT3X was unable to detect changes resulting from an intervention in school hours (ActivPAL = −34.7 min·9 h−1 vs GT3X = +6.7 min·9 h−1; P < .05). Conclusions: The authors conclude that GT3X (cut-point of <100 counts·min−1) overestimated sedentary time of free-living activities and did not detect changes resulting from a classroom standing desk intervention in adolescents.
Danilo R. Silva, Cláudia S. Minderico, Pedro B. Júdice, André O. Werneck, David Ohara, Edilson S. Cyrino and Luís B. Sardinha
André O. Werneck, Evelyn C.A. Silva, Maria R.O. Bueno, Lidyane Z. Vignadelli, Adewale L. Oyeyemi, Catiana L.P. Romanzini, Enio R.V. Ronque and Marcelo Romanzini
Purpose: To investigate the association between patterns of sedentary behavior and obesity indicators among adolescents. Methods: This was a cross-sectional study conducted among 389 adolescents (186 boys) aged 10–14 years. Body mass index, body fat (skinfolds), and waist circumference were adopted as outcomes. Sedentary behavior patterns (total time, bouts, and breaks) measured through accelerometry (GT3X and GT3X+; ActiGraph, Pensacola, FL) were adopted as exposures. Peak height velocity, moderate to vigorous physical activity (accelerometer), cardiorespiratory fitness (Léger test), sex, and chronological age were adopted as covariates. Linear regression models adjusted for covariates were used to determine associations between outcome and exposure variables. Results: The mean age of adolescents was 11.8 (0.7) years. Boys were more active than girls (P < .001). Accumulating shorter bouts (1–4 min) of sedentary behavior was negatively associated with body mass index (β = −0.050; 95% confidence interval [CI], −0.098 to −0.003) and waist circumference (β = −0.133; 95% CI, −0.237 to −0.028). Similarly, a higher number of breaks in sedentary behavior were negatively associated with body mass index (β = −0.160; 95% CI, −0.319 to −0.001) and waist circumference (β = −0.412; 95% CI, −0.761 to −0.064). Conclusion: Shorter bouts of sedentary behavior (1–4 min) and a higher number of breaks of sedentary behavior were associated with lower adiposity. Our findings also suggest that breaking up sedentary time to ensure bouts of sedentary behavior are short might contribute to the prevention of obesity in adolescents.
André O. Werneck, Adewale L. Oyeyemi, Rômulo A. Fernandes, Marcelo Romanzini, Enio R.V. Ronque, Edilson S. Cyrino, Luís B. Sardinha and Danilo R. Silva
Background: This study aims to describe the regional prevalence and patterns of physical activity (PA) and sedentary behavior among Brazilian adolescents. Methods: Data from the Brazilian Scholar Health Survey, a nationally representative survey of ninth-grade adolescents [mean age: 14.29 y (14.27–14.29)] conducted in 2015 (n = 101,445), were used. Outcomes were television viewing, sitting time (ST), total PA, and active traveling collected via self-administered questionnaire. Information on frequency of physical education classes and type of school was collected from the school’s director. Frequencies with 95% confidence intervals were used to determine the prevalence and patterns of outcomes. Results: Higher prevalence of PA (≥300 min/wk) and ST (>4 h/d) was found in Midwest (PA = 38.0%; ST = 44.5%), South (PA = 37.6%; ST = 50.1%), and Southeast (PA = 36.1%; ST = 49.3%) compared with Northeast (PA = 29.7%; ST = 36.9%) and North (PA = 34.4%; ST = 34.8%) regions of Brazil. ST was higher among adolescents from private schools (51.5%) than public schools (42.9%), whereas active traveling was greater among students of public schools than private schools (62.0% vs 34.4%). Most inequalities in outcomes between capital and interior cities were in the poorest regions. Conclusions: The results indicate that national plans targeting regional inequalities are needed to improve PA and to reduce sedentary behavior among Brazilian adolescents.
André O. Werneck, Edilson S. Cyrino, Paul J. Collings, Enio R.V. Ronque, Célia L. Szwarcwald, Luís B. Sardinha and Danilo R. Silva
Background: This study describes the levels and patterns of television (TV) viewing in Brazilian adults and investigates associations of TV viewing with hypertension, type 2 diabetes, and heart disease. Methods: Data from the Brazilian Health Survey, a nationally representative survey that was conducted in 2013 (N = 60,202 men and women aged ≥18 y), were used. Information regarding TV viewing, physician diagnoses of type 2 diabetes, hypertension, and heart disease was collected via interview-administered questionnaire. Data on covariables (including chronological age, educational status, skin color, sodium consumption, sugar consumption, tobacco smoking, alcohol consumption, and leisure-time physical activity) were also self-reported. Logistic regression models and population attributable fractions were used for the etiological analyses. Results: The prevalence (95% confidence interval) of >4 hours per day of TV viewing was 12.7% (12.0–13.4) in men and 17.5% (16.8–18.3) in women. Men and women being younger or older, moderately educated, living alone, smoking tobacco, and drinking alcohol were associated with higher reported TV viewing time. Odds ratios (95% confidence interval) revealed that >4 hours per day of TV viewing was associated with type 2 diabetes [male: 1.64 (1.23–2.17) and female: 1.33 (1.09–1.63)], hypertension [male: 1.36 (1.14–1.63) and female: 1.20 (1.05–1.37)], and heart disease [male: 1.96 (1.43–2.69) and female: 1.30 (1.00–1.68)]. Exceeding 4 hours per day of TV viewing was responsible for 6.8% of type 2 diabetes, 3.7% of hypertension, and 7.5% of heart disease cases. Conclusions: Independent of covariates, >4 hours per day of TV viewing was associated with type 2 diabetes, hypertension, and heart disease. High volumes of TV viewing are prevalent and appear to contribute to chronic disease burden.