Trend analysis, gender-specific patterns, and age dynamics of childhood and adolescent obesity: insights from the Tehran lipid and glucose study

Childhood and adolescent obesity pose significant challenges to global health, with escalating prevalence and associated short- and long-term health consequences. This longitudinal study leveraged data from the Tehran Lipid and Glucose Study (TLGS) to investigate the trends of obesity among Tehranian children and adolescents over a 21-year period. Utilizing data from TLGS phases I to VII (1999-2021), we included 3845 participants aged 3-18 years at the beginning of phase I. Anthropometric measures, including height and weight, were collected, and body mass index (BMI) was calculated. Childhood obesity (2-19 years) was defined as BMI-for-age > 2SD based on World Health Organization (WHO) standards, and adult obesity was defined as BMI ≥ 30. Descriptive statistics, trend analysis, prevalence calculations, odds ratios, and interaction analyses were employed for data interpretation. The mean BMI increased from 18.46 ± 4.37 kg/m² at Phase I to 26.36 ± 5.03 kg/m² at Phase VII. Boys exhibited a greater increase in BMI than girls, and age at study entry influenced BMI trajectories. The prevalence of obesity rose from 6.4% at Phase I to 21.5% at Phase VII, with a more pronounced increase in boys. Odds ratios for obesity steadily increased across phases, indicating a growing risk. Interaction analyses revealed age-specific dynamics, with older participants demonstrating lower odds ratios initially but higher odds ratios in later phases. Our study shows a worrisome increase in childhood obesity among Tehranian children and adolescents over 21 years. Sex- and age-specific trends emphasize the necessity for targeted interventions, informing policymakers, healthcare practitioners, and educators regarding public health strategies and interventions against the obesity epidemic.