Changes in physical growth and nutritional status in adolescents in a region of Chile

Introduction: the demographic changes experienced in recent decades have positioned overweight and obesity among the most urgent public health problems. Objectives: to evaluate secular trends in the physical growth and nutritional status of adolescents over a 20-year interval. Methodology: a longitudinal trend study was designed in two cohorts (1997 and 2017) in adolescents aged 11.0 to 17.0 years. Two cohorts were considered. For the 1997 cohort, 939 adolescents were selected and 1026 for 2017. Weight and height were assessed. Body mass index (BMI) was calculated. Nutritional status categories were determined using WHO cut-off points: underweight, normal weight, overweight and obese. Results: this study showed positive trends in physical growth in body weight (in males from ~2.8 to 9.35 kg and in females from 3.83 to 9.9 kg). Height only increased in boys at younger ages (between 11 and 13 years, from ~3.5 to 6.8 cm). In addition, BMI increased significantly in both sexes and at all ages over 20 years (in males it increased from ~1.43 to 2.43 kg/m2 and in females from ~1.8 to 3.27 kg/m2). The prevalence of underweight disappeared, normal weight decreased by 15.2 %, and overweight increased by 6.3 % and obesity by 9.8 %. Conclusions: the study found a significant increase in BMI and prevalence of overweight and obesity in adolescents in south-central Chile over the last 20 years. This suggests the urgent need to implement programs that promote healthy lifestyles to counteract this trend and improve the well-being of adolescents.