MON-106 Prevalence and Incidence of Obesity in Children and Young Adults in Korea: The Kangwha Study

Childhood obesity is a major global concern, arousing a variety of health problems and high social costs. The prevalence of childhood obesity has increased, but plateaued during the first decade of the 21th century in developed countries. Many previous studies reported cross-sectional data with prevalence of obesity, but researches about incidence of obesity based on longitudinal data is insufficient, especially in Korean population. In this study, we analyzed prevalence and incidence of overweight and obesity in Korean children and young adults from a prospective cohort study. We analyzed data from the Kangwha study, which is a community-based prospective cohort study began in 1986 with 6-year-old, first-grade elementary school students in Kangwha county, South Korea. The Kangwha study is a dynamic cohort, which the number of participants was expanded several times during the follow-up period. The study was started with 482 children, which expanded to total 1,223 participants. The participants were examined annually until 1997, which is 17 years of age. Four adulthood follow-up studies were performed in 1999, 2005, 2010, and 2015. The data includes a 30-year period (1986–2015), with total 16 observations conducted. We used the 2007 Korean National Growth Charts to determine cutoffs for normal weight, overweight, and obesity in children. In adulthood, Asia-Pacific classification of obesity from World Health organization (WHO) recommendation was applied to define overweight and obesity. When the children were in their first-grade of elementary school, prevalence of overweight was 1.04% and obesity was 0.62%. Prevalence of overweight and obesity increased since age 10 (fifth-grade in elementary school) (overweight 4.44%, obesity 1.18%), reaching 7.34% and 3.39% in age 12 (first-grade in middle school), and 9.5% and 5.37% in age 17 (third-grade in high school). Prevalence of overweight and obesity in girls were higher than in boys throughout childhood. Annual incidence of obesity showed small peak at entering middle school (2.1%, age 12), and another peak at third-grade in high school (2.33%, age 17). Also, a positive correlation was found between body mass index (BMI) in younger ages and follow-up BMI. Prevalence of overweight and obesity increased since senior years of elementary school, and more prominent in girls. Detailed study design and larger population would be required for subsequent investigations.