What are the correlates of intention to be physically active in Brazilian adolescents? A network analysis.

OBJECTIVE: The current study aimed to explore the association of individual characteristics, social and environmental factors - school and region - in the intention to be physically active in Brazilian adolescents. METHODS: This is a cross sectional study based on the third edition of the National School Health Survey. The study included a total of 53,937 adolescents. To assess the intention to be physically active, only who engaged in less than 300 min of physical activity per week were included. Participants were asked: "If you had the opportunity to practice physical activity most days of the week, what would your attitude be?" Individual characteristics, physical activity domains, social factors, school, and regional environments were used as exposures. Network analysis was utilized to evaluate the associations. RESULTS: We observed that boys had higher intentions to be physically active compared to their peers, as did adolescents who perceived themselves as fat. In addition, students from private schools show a higher intention to regularly engage in physical activities, and in general, private schools offer more extracurricular physical activities. CONCLUSION: In conclusion, individual factors such as sex and body image perception, and environmental factors such as school administrative dependency and availability of extracurricular activities had a significant contribution to the intention to be physically active among Brazilian adolescents.

Prevalence and sociodemographic correlates of physical activity and sitting time among South American adolescents: a harmonized analysis of nationally representative cross-sectional surveys.

BACKGROUND: To identify the prevalence and sociodemographic correlates of different domains of physical activity (PA) and higher sitting time among South American adolescents. METHODS: Data from national surveys of 11 South American countries were analyzed, and comprised information on 166,901 adolescents. PA (≥ 60 min/day of moderate-vigorous PA), physical education classes (PEC) (≥ 3 classes/wk), active commuting to school (≥ 1 d/wk), and higher sitting time (≥ 3 h/d) were self-reported. Sociodemographic correlates, such as gender, age, and food security status were explored using a random effect meta-analysis for logistic parameters. RESULTS: Recommended PA ranged between 7.5% (Brazil) and 19.0% (Suriname). Peru (2.2%) and Guyana (43.1%) presented the lowest prevalence of PEC and active commuting to school, respectively. Higher sitting time was less prevalent in Bolivia (24.6%) and more prevalent in Argentina (55.6%). Compared to girls, boys were more prone to reach recommendations for PA [OR = 1.94(1.65;2.28)]; to reach ≥ 3 PEC [OR = 1.17(1.04;1.33)] and to be active in commuting to school [(OR = 1.14(1.06;1.23)], but less prone to higher sitting time [OR = 0.89(0.82;0.96)]. Older adolescents had less odds of reach PA guidelines [OR = 0.86(0.77; 0.97)] and accumulated higher sitting time [OR = 1.27(1.14;1.41)]. Adolescents with food insecurity reported more PEC [OR = 1.12(1.04;1.21)] and active commuting to school [OR = 1.12(1.02;1.22)] but had less higher sitting time than their food security pairs [OR = 0.89(0.81;0.98)]. CONCLUSIONS: Few adolescents reach the PA recommendation. Actions aiming the promotion of PA and the reduction of sitting time must consider girls and older adolescents as target groups, as well as the specifics of each country.

Global prevalence and gender inequalities in at least 60 min of self-reported moderate-to-vigorous physical activity 1 or more days per week: An analysis with 707,616 adolescents.

BACKGROUND: Guidelines recommend that adolescents should accumulate an average of 60 min per day of moderate-to-vigorous physical activity (MVPA). However, using only this cut-off could hide important information. For instance, from a population-level point of view, increasing physical activity for those with no or low physical activity could provide more health benefits than increasing physical activity for those with intermediate levels. Also, including a more sensitive cut-point of ≥1 day per week could be an additional strategy for identifying those with low access/opportunities for physical activity practice. Thus, the current study aims to estimate the prevalence of ≥60 min of MVPA ≥1 days per week among adolescents globally, and to describe any relevant gender inequalities. METHODS: We used representative datasets from 146 countries/territories collected between 2003 and 2019. MVPA was self-reported. Participants were grouped into younger (≤14 years old) and older (>14 years old) adolescents. Crude Poisson regression models were used to identify the relative differences in ≥60 min of MVPA ≥1 days per week between boys and girls, and random-effects meta-analysis models were used to identify the pooled estimates. Analyses were stratified by country and region. RESULTS: Approximately 80% of both younger and older adolescents reported ≥60 min of MVPA ≥1 days per week. This prevalence was ≥94% in Europe and Central Asia and North America, while the estimates for the other regions were <77%. The prevalence of ≥60 min of MVPA ≥1 days per week was higher among boys than girls, with the largest differences occurring among the oldest adolescents (PR≤14y: 1.04 (95% confidence interval (95%CI): 1.03‒1.04) vs. PR>14y: 1.09 (95%CI: 1.08‒1.10)). CONCLUSION: Approximately 8 out of 10 adolescents reported accumulating ≥60 min of MVPA ≥1 day per week, with notable differences between regions. Gender differences were observed in several countries, especially among the oldest adolescents. Priorities for physical activity promotion among adolescents should include increasing access/opportunities for physical activity among those who do not achieve ≥60 min of MVPA ≥1 days per week and reducing gender inequalities.

The moderating effect of physical activity on the association between screen-based behaviors and chronic diseases.

We analyzed the associations of screen-based behaviors with obesity, hypertension, and diabetes, and the moderation of different physical activity (PA) domains in these associations. We used data from the 2019 Brazilian National Health Survey, including data from 80,940 adults (mean age of 32.6 years). TV viewing, other screens (PC, tablet, and cell phone), PA domains (leisure-time, occupational, and transport) were collected via interview. Logistic regression models were used. There was a dose-response association of higher TV viewing with diabetes. Within the groups with medium and higher time spent on other screens, those with < 150 min/week in leisure-time PA increased the odds for obesity [1-2.9 h/day: OR = 1.18 (1.01, 1.39)] and hypertension [1-2.9 h/day: OR = 1.29 (1.08, 1.53); ≥ 6 h/day: OR = 1.47 (1.03, 2.09)]. Likewise, among the participants who spent ≥ 6 h/day of TV viewing, those with < 150 min/week of occupational PA presented higher odds for hypertension [OR = 1.61 (1.03, 2.53)]. In the group with higher use of other screens, < 150 min per week of occupational PA was associated with lower odds for obesity [1-2.9 h/day: OR = 0.81 (0.68, 0.97)] and hypertension [≥ 6 h/day: OR = 0.65 (0.44, 0.98)]. In conclusion, the associations of other screens with obesity and hypertension were strongest among those without leisure-time PA, while the moderator role of occupational PA was not clear.