Determinants of overweight tracking from childhood to adolescence: a 5 y follow-up study of Hat Yai schoolchildren

Abstract

To study the determinants of overweight tracking from childhood to adolescence of Hat Yai schoolchildren. A longitudinal study. Primary and secondary schools of Hat Yai municipality, southern Thailand. 2252 schoolchildren recruited in 1992 and follow-up for 5y. Child's annual body mass index (BMI, kg/m2) from 1992 to 1997; parental BMIs, parental income, and family history of diseases by a questionnaire completed by parents in 1992. Prevalence of overweight of males using the 85th percentile of the U S First National Health and Nutritional Examination Survey reference for age and sex as a cut-off point increased from 12.4% in 1992 to 21% in 1997, whereas that of females went down from 15.2 to 12.6. At the end of the fifth year, 11.8% of children remained overweight while 4.5% became overweight. Comparing to the non-overweights, the risk for becoming an overweight adolescent of an overweight boy was 8.2 (95% confidence interval (CI) = 6, 11.2) whereas that of the overweight girls was 20 (95% CI = 12.4, 32.3). The generalized estimating equations model predicted an increase in child BMI associated with having a father or a mother with high BMI, a family history of obesity, a monthly income greater than 5000 baht, and a lower level of exercise than their peers. Secular increase in BMI was also observed. Predictors of overweight tracking found in this study would be useful to select children at risk for preventive intervention.