The objective of this study was to provide current estimates of the prevalence and examine trends of overweight and obesity in children and adolescents.

Height and weight measurements from 183,159 (112,974 in 1997, 70,185 in 2005) children and adolescents aged 2 to 18 years were obtained via the 1997 and 2005 National Growth Survey . Obesity among children and adolescents was defined as being at or above the 95th percentile of the gender-specific body mass index (BMI) for age in the 2007 Korean National Growth Charts or a BMI of 25 or higher; overweight was defined as being at or above the 85th percentile to less than the 95th percentile BMI.

In 2005, 9.7% (11.3% for boys, 8.0% for girls) of South Korean children and adolescents were obese; 19.0% (19.7% for boys, 18.2% for girls) were overweight or obese. The overall prevalence of obesity increased from 5.8% in 1997 to 9.7% in 2005 (from 6.1% in 1997 to 11.3% in 2005 for boys and from 5.5% in 1997 to 8.0% in 2005 for girls); the increasing trend was most evident in boys, especially those aged 13-18 years.

The prevalence of obesity among children and adolescents increased significantly during the eight-year period from 1997 to 2005. This study suggests that we need to make a priority of developing strategies to control obesity in children and adolescents; the potential health effects of increases in obesity are of considerable public health importance.