Prevalence of obesity among Thai schoolchildren: a survey in Khon Kaen, Northeast Thailand

Background: There is a worldwide increase in obese children and adolescents. No systematized biometric data are available to confirm this trend in Thailand. Objective: Estimate the prevalence of obesity among 12- to 18-years-old attending the secondary school in the municipality of Khon Kaen, Northeast Thailand. Materials and methods: We used stratified, two-stage, cluster sampling to select 7,096 healthy boys and girls from 12,021 students of grades 7 to 12 at three government schools. Height and weight were measured to calculate body mass index (BMI) (weight (kg)/height (m)2). Sex-specific, BMI-for-age growth charts were created from the data on the 2,593 boys and 4,503 girls (between 12 and 18 years of age) using simple random sampling. Sex-specific BMI-for-age growth charts and the weight-for-height (W/H) were used to estimate the prevalence of obesity and overweight. Results: The respective national prevalence of obese and overweight children was 4.9% and 9.5% in the BMI-forage, the rates between boys and girls being comparable. There were no significant differences in the prevalence of either obesity or overweight with increasing age. In the Thai standard W/H, 13.7% of the children were obese and 5.3% were overweight. Obesity was more prevalent n boys (18.9%) than girls (10.8%) and decreased with age. The prevalence of overweight did not change with age regardless of gender. Conclusion: Obesity among children in Khon Kaen was similar to, or less prevalent than that reported for other areas of Thailand. The prevalence of obesity needs to be judged by the same (or similar) criteria before any comparison among various studies is done.