Papel da obesidade, do estilo de vida e dos fatores imunológicos no comprimento dos telômeros em crianças e adolescentes.

Abstract

INTRODUCTION: The increase in obesity in children and adolescents is related to environmental changes such as unhealthy eating habits, sedentary lifestyles, and lack of physical activity. The accumulation of fat in the body triggers inflammation, which increases cell proliferation and telomere shortening. External factors and lifestyle play an important role in the shortening of telomeres, which have the function of protecting genetic material. Many complications associated with obesity are related to telomere shortening. GENERAL OBJECTIVE: To verify the role of obesity, lifestyle, immunologic and sociodemographic factors on telomere length in children and adolescents. MANUSCRIPT 1: Objective: To verify the role of sociodemographic factors in the associations between behavioral and immunologic factors, body mass index (BMI), and telomere length in children and adolescents. Methods: Cross-sectional study of 476 children and adolescents aged 7 to 17 years, 57.6% female, from a community in southern Brazil. Sociodemographic variables used were age, sex, school zone, skin color, and socioeconomic status. Behavioral variables (physical activity, sleep, and screen time) were self-reported using an adapted questionnaire. Weight and height were measured to calculate BMI. Blood was drawn to assess telomere length using the salting out technique and immunologic parameters (leukocytes, neutrophils, and lymphocytes) and to calculate the Systemic Immune Inflammation Index (SII). Associations between variables were tested using multiple linear regression stratified by sociodemographic variables. Results: An inverse association was found between BMI and telomere length in adolescents (β: -0.205; 95% CI: -0.376; -0.033), non whites (β: -0.344; 95% CI: -0.674; -0.014), and rural students (β: -0.336; 95% CI: -0.602; -0.070). Leukocytes were directly associated with telomere length in urban students (beta: 0.127; 95% CI: 0.005; 0.244). Lymphocytes showed a direct association with telomere length in non-whites (beta: 0.248; 95% CI: 0.050; 0.446). IBS showed a direct association with telomere length in urban school children (beta: 0.134; 95% CI: 0.011; 0.256). Conclusions: The results suggest that the relationship between BMI, immunological factors and telomere length differs between different sociodemographic groups, with associations occurring only in specific groups. MANUSCRIPT 2: Objective: To verify the relationship between screen and sleep time, BMI and immunological factors with telomere length according to leisure-time physical activity (PA) in children and adolescents. Method: A cross-sectional study comprising a sample of 476 schoolchildren of both sexes aged between seven and 17 from a municipality 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 (practicing some physical activity). The associations of screen and sleep time, BMI and immunological factors with telomere length were tested by multiple linear regression models, with the sample divided according to the leisure-time physical activity practice of the schoolchildren. Results: In the inactive schoolchildren, an inverse association was found between BMI and telomere length (β:-0.239; 95% CI: -0.468; -0.010) and a direct relationship of leukocytes (β: 0.151; 95% CI: 0.029; 0.278) and neutrophils (β: 0.131; 95% CI: 0.008; 0.254) with telomeres. No association was found between screen time and sleep time and telomeres. Among students who performed any PA, no association was found. Conclusion: The associations between telomeres, BMI and immunological factors were identified exclusively in inactive schoolchildren. These results suggest that the association between BMI and immunological factors and telomere length may be influenced by physical activity. FINAL CONSIDERATIONS: The results highlight the complexity of the interactions between BMI, immunological factors and telomere length, revealing significant variations between different sociodemographic groups. The influence of physical activity on telomere length underscores the need for personalized approaches to health promotion. These findings provide crucial insights for future research in the local child and adolescent population, reinforcing the need for awareness of healthy habits and helping to prevent future problems related to overweight and obesity.