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Objective: The aim of this study was to analyze isolated and combined associations of physical inactivity excessive screen time with negative self-rated health, according to sex, among school adolescents., Methods: In this cross-sectional study conducted with 2,517 adolescents in Amazonas State, participants were asked about their self-rated health with the following question: How do you rate your health? Responses were dichotomized into positive (excellent and good) and negative (regular, bad, and terrible). Information on sex, age group, family income, physical activity, and screen time (watching TV, using a computer, or playing video games) was collected through a self-administered questionnaire. Adolescents simultaneously classified as physically inactive (<60 min/day) and having excessive screen time (>2 h/day) were considered to have two risk factors. Data was analyzed using binary logistic regression., Results: Out of every 10 adolescents, 2 had a negative self-rated health. After adjusting for age and family income, there were no isolated or combined associations between physical inactivity or excessive screen time and negative self-rated health in girls. In boys, negative self-rated health was associated with insufficient levels of physical activity (odds ratio [OR]: 2.39; 95% confidence interval [CI]: 1.03-5.59) and with the accumulation of two risk factors (OR: 1.61; 95%CI 1.10-2.34)., Conclusions: Being insufficiently active and the combination of physical inactivity and excessive screen time become exposure factors to the negative self-rated health of adolescent boys.

Adolescence is a period characterized by large accumulation of bone mass. Body composition is an important determinant of bone mass. This study aimed to assess the relationship of bone mass with lean mass (LM) and fat mass (FM) in normal-weight and overweight adolescents with consideration of sex, sexual maturation and physical activity covariates. A total of 118 adolescents (60 girls and 58 boys) aged between 10 and 14 years participated in the study. Individuals were classified as normal weight or overweight according to body mass index. Bone mineral density (BMD), bone mineral content (BMC), LM, and FM were measured by dual-energy X-ray absorptiometry. In normal-weight adolescents, LM ( β  = 0.725, p < 0.001) and FM ( β  = 0.185, p = 0.019) were associated with lumbar spine BMC, whereas in overweight adolescents only LM ( β  = 0.736, p < 0.001) was associated with lumbar spine BMC. Furthermore, in the normal-weight group, FM and LM were associated with total body less head BMD (LM, β  = 0.792, p < 0.001; FM, β  = 0.257, p = 0.007) and lumbar spine BMD (LM, β  = 0.553, p < 0.001; FM, β  = 0.199, p < 0.035). In the overweight group, only LM was associated with total body less head BMD ( β  = 0.682, p < 0.001) and lumbar spine BMD ( β  = 0.528, p < 0.001). LM was the main predictor of bone mass in normal-weight and overweight adolescents. FM was associated with bone mass in normal-weight adolescents only. LM may be considered an important and useful marker in adolescents, when investigating bone health in this population. Activities that promote LM gain to reduce the risk of bone fractures and diseases in adulthood are recommended., Competing Interests: The authors declare there are no competing interests., (©2022 Bim et al.)

Objective: To verify the prevalence of abdominal obesity with the waist-to-height ratio (WHtR) and associated factors in adolescents from a city in Southern Brazil., Methods: A total of 960 adolescents (494 boys) aged 15-18 years old participated in this study. The dependent variable was WHtR; independent variables were self-reported age, economic level, sexual maturation, physical activity level, screen time, and body fat. Data were analyzed using descriptive statistics and logistic regression., Results: It was observed that 36.7% of the adolescents presented high WHtR (50.2% in girls and 23.9% in boys). Regardless of sex, adolescents with high body fat were more likely of having high WHtR (boys: Odds Ratio [OR] 29.79; 95% confidence interval [95%CI] 16.87-52.62; girls: OR 19.43; 95%CI 10.51-35.94). In girls, high WHtR was associated with age (OR 1.83; 95%CI 1.17-2.87), and in boys, with economic level (OR 2.34; 95%CI 1.01-5.45)., Conclusions: One in each three adolescents has abdominal obesity. Among adolescents with high body fat, girls aged 15-16 and boys with high-income are the groups most exposed to abdominal obesity.