Sedentary behavior based on screen time: prevalence and associated sociodemographic factors in adolescents

<div><p>Abstract The aim of this study to estimate the prevalence of sedentary behavior based on screen time (≥ 2-hour day) and to identify the association with sociodemographic factors among adolescents in a city in southern Brazil. This is an epidemiological survey of school-based cross-sectional study with students aged 14-19 years in the city of São José/SC - Brazil. Self-administered questionnaire was used, containing information sociodemographic, level of physical activity and about screen time. Descriptive statistics were performed, and odds ratios were estimated using binary logistic regression and 95% confidence level. The prevalence of excess screen time was 86.37% followed by computer use (55.24%), TV use (51.56%) and Videogame use (15.35%). Boys had higher prevalence of excessive video game use. Those of skin color different from white and mothers who studied less than eight years were more likely to watch too much TV, and those of low economic level were more likely of having excessive screen time. Girls of skin color different from white were more likely to watch too much TV, and those aged 14-16 years were more likely to have videogame use time and total time screen above recommended.</p></div

Association between different contexts of physical activity and abdominal obesity and excess weight in adolescents.

<div><p>Abstract Aim: To investigate the association between different contexts of physical activity (school commuting, participation in Physical Education classes, school recess, physical activity to improve muscular strength / endurance and overall physical activity) with abdominal obesity and excess weight in adolescents. Method: Cross-sectional study with 1,132 adolescents (14-19 years), enrolled in public schools in São José, Brazil. Information regarding the contexts of physical activity was obtained through questionnaires. The anthropometric indicators used to identify excess weight and abdominal obesity were body mass index (BMI) and waist circumference (WC). Binary logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI). Results: Adolescents who actively commuted to school for 10 minutes or longer were 36% less likely (OR: 0.64, 95% CI: 0.58 a 0.71) of having abdominal obesity investigated by WC and 25% less likely (OR: 0.75, 95% CI: 0.65 a 0.86) of having excess weight investigated by means of BMI. The other physical activity contexts were not associated with anthropometric indicators. Conclusion: Active commuting to school was associated with lower odds of having abdominal obesity and excess weight in adolescents. Thus, active commuting to school can be an alternative for maintaining adequate levels of body composition.</p></div

Comparison of lumbar force between pubertal and post-pubertal adolescents: interference of physical growth, body fat and lifestyle.

<div><p>Abstract Aim: To compare performance in the lumbar force test in pubertal and post-pubertal adolescents by controlling the interference of physical growth, body fat, screen time and physical activity. Methods: A cross-sectional study with 933 adolescents (492 girls) aged 14-19 from the city of São José, Brazil. Lumbar strength was assessed using the isometric lumbar extension test proposed by the Canadian Society of Exercise Physiology. Sexual maturation was classified according to Tanner’s criteria. Physical growth variables (age, body weight, stature, BMI), body fat (triceps and subscapular skinfolds), sedentary behavior based on screen time and overall physical activity were controlled in the Analysis of Covariance (ANCOVA), with a significance level of 5%. Results: Post-pubertal boys presented higher lumbar force compared to pubertal ones only when interference of BMI, body fat, screen time and physical activity was controlled. Pubertal girls presented higher lumbar force compared to post-pubertal ones, both when controlling the analysis for the studied variables and when not controlled by them. Conclusion: BMI, body fat, screen time and physical activity interfere in the difference in lumbar strength of boys, in which post-pubertal boys presented better performance in lumbar force compared to pubertal ones. Regardless of interference or not of these variables, pubertal girls presented better performance in lumbar force when compared to post-pubertal ones.</p></div

SECULAR CHANGES IN AEROBIC FITNESS LEVELS IN BRAZILIAN CHILDREN

<div><p>ABSTRACT Introduction: Aerobic fitness is a component of physical fitness related to health and has great importance in the prevention of cardiovascular diseases. Objective: To verify the secular changes in aerobic fitness levels and to identify factors over a decade related to low levels of aerobic fitness in Brazilian children. Methods: This secular change study was carried out from 1999 to 2010 with 11,083 children aged from six to nine years, of both sexes, living in all regions of Brazil. The aerobic fitness was assessed by the 9-minute run test. The independent variables were sex, age, geographic region, area of residence, and nutritional status. The “t” test was used for independent samples and analysis of variance, chi-square test, and Poisson regression were used to estimate prevalence ratio (PR) and confidence intervals of 95% (CI 95%). Results: No significant changes in the distance covered in the 9-minute run test and in the prevalence of low levels of aerobic fitness were observed from 1999 to 2010. The population subgroups most likely to have low aerobic fitness levels were students aged seven years, those in the Midwestern, Southeast, and South of Brazil, those living in rural areas and those with overweight and obesity. Conclusions: Over a decade, low levels of aerobic fitness were present in four fifths of Brazilian children and this picture did not change. Low levels of aerobic fitness affected more children above six years old, living in the economically most favored regions of Brazil, in rural areas and with overweight.</p></div

Values of mean and standard deviation of VO₂max according to the anthropometric indicators of adolescents.

<p>Values of mean and standard deviation of VO₂max according to the anthropometric indicators of adolescents.</p

Total and stratified by sex of mean and standard deviation of age, height, body mass, anthropometric indicators and VO₂max of adolescents.

<p>Total and stratified by sex of mean and standard deviation of age, height, body mass, anthropometric indicators and VO₂max of adolescents.</p

Odds ratios and 95% confidence intervals, crude and adjusted, between the simultaneous presence of eight anthropometric indicators of excess body fat and independent variables.

<p>Odds ratios and 95% confidence intervals, crude and adjusted, between the simultaneous presence of eight anthropometric indicators of excess body fat and independent variables.</p

Prevalence of combinations of anthropometric indicators in adolescents.

<p>Prevalence of combinations of anthropometric indicators in adolescents.</p

Characteristics of anthropometric indicators of adolescents according to demographic and economic variables.

<p>Characteristics of anthropometric indicators of adolescents according to demographic and economic variables.</p

Prevalence of suicidal thoughts and behaviors and its association with body dissatisfaction in adolescents

<p></p><p>ABSTRACT Objective To estimate the prevalence of suicidal thoughts and behaviors and its association with body image dissatisfaction in adolescents. Methods Participants were 1,090 adolescents (501 male and 589 female), with mean age of 16.2 (1.1) years, who were high school students in Sao Jose-SC. In a self-administered questionnaire, adolescents answered sociodemographic questions (sex, age), sexual maturation, body dissatisfaction (figure rating scale), suicidal thoughts and behaviors (ideation, planning and attempts), and had body weight and height measured to calculate the body mass index (BMI = body weight divided by squared height). Binary logistic regression was used to data analysis. Results Greater prevalence of ideation, planning and suicidal attempts was found among female than male. Adolescents who were dissatisfied by thinness and by overweight were more likely to ideation and planning suicide. No associations between suicidal attempts and body image dissatisfaction were found. Conclusions Females had higher prevalence of ideation, planning and attempt than males. Regardless of sex, age, BMI and sexual maturation, the adolescents who were dissatisfied with their body (both by thinness and by overweight) were more likely to ideation and planning the suicide, compared to those who were satisfied. Giving that these adolescents are in school age, the school can be an agent of discussion on the subject, assisting to prevent body dissatisfaction and suicidal outcomes. Other professionals who work with adolescents and relatives need to pay attention to these issues.</p><p></p