Age, period and birth cohort effects on the prevalence of overweight and obesity among Taiwanese adolescents: A national population-based study

Background The age-period-cohort effects on youth overweight and obesity among junior and senior high school students in Taiwan is not clear. Methods We utilized the 2006-14 nationally representative School Physical Fitness Dataset. Based on the International Obesity Task Force cutoff criteria, a log-linear age-period-cohort analysis was performed to determine the influence of age, period and cohort on the trend in being overweight, obese and severely obese for both sexes. Results The final dataset included 1073173 individuals (n = 520 382 boys and 552 791 girls). For girls, the prevalence of overweight and obesity declined with age, and the prevalence of overweight declined over time. For boys, the prevalence of overweight and obesity declined with age and over time from 2006 to 2014. The prevalence of severe obesity declined over time and increased with age for the boys. The younger birth cohorts had greater odds of being overweight, obese and severely obese than the older birth cohorts. Conclusions After differentiating the age-period-cohort effects, the data suggested a decreasing temporal trend in overweight and obesity among adolescents in Taiwan from 2006 to 2014. Among the birth cohorts of the 1990s, the younger cohorts had greater odds of being overweight and obese than the older cohorts when they reached adolescence.