Secular Trends of Overweight and Obesity in Young Southern Californians 2008-2013

OBJECTIVE: To investigate secular trends in pediatric obesity in Southern California between 2008 and 2013.

STUDY DESIGN: In a population-based cohort study, measured weight and height were extracted from electronic health records of 1,331,931 patients aged 2-19 years who were enrolled in an integrated prepaid health plan between 2008 and 2013. Outcomes were the prevalence of overweight and obesity (body mass index-for-age ≥85th percentile).

RESULTS: The prevalence of obesity was 19.1% in 2008 and decreased by 1.6% (95% CI, 1.7%-1.5%) by 2013, corresponding to a relative decline of 8.4%. A significant decline was observed across all ages, sexes, races, and socioeconomic groups, but the magnitude of the decrease varied. The relative decline in obesity was stronger in boys (-9.3%) than in girls (-7.2%), in children aged 2-5 years (-15.4%) and 6-11 years (-11.8%) than in adolescents aged 12-19 years (-4.5%), and in whites (-12.6%) and Asians (-12.2%) than in Hispanics (-6.9%) and African Americans (-7.5%).

CONCLUSION: Secular trends from this large population-based cohort suggest that overweight and obesity in boys and girls are declining across age and racial/ethnic groups. However, the declines are less pronounced in adolescents compared with children, in girls, and in some minority groups. Programs addressing childhood obesity may need to be targeted.