The association of telomere length with body mass index and immunological factors differs according to physical activity practice among children and adolescents.

ABSTRACT

BACKGROUND: This study aims to verify the relationship between screen and sleep time, body mass index (BMI) and immunological factors with telomere length according to leisure-time physical activity (PA) in children and adolescents. METHODS: A cross-sectional study involving a sample of 476 schoolchildren of both sexes, aged seven to 17 years, from a community in southern Brazil. Behavioral variables (PA, sleep time, and screen time) were self-reported using a questionnaire. PA was classified as inactive and any PA (doing some physical activity). The associations of screen time, sleep time, BMI, and immunologic factors with telomere length were tested using multiple linear regression models, with the sample divided according to the schoolchildren's leisure-time physical activity practices. RESULTS: An inverse association between BMI and telomere length (ß -0.239; 95% CI -0.468; -0.010) and a direct association of leukocytes (ß 0.151; 95% CI 0.029; 0.278) and neutrophils (ß 0.131; 95% CI 0.008; 0.254) with telomeres were found in the inactive students. No association was found between screen time and sleep time and telomeres. No association was found among students who engaged in any PA. CONCLUSION: The associations between telomeres, BMI, and immunologic factors were found only in inactive students. These results suggest that the association between BMI and immunological factors and telomere length may be influenced by physical activity.