Secular increases in weight, height and body mass index among school children of Hat Yai, Thailand: a 5 years follow-up study.

Upward trend of growth and overweight has been reported from developed countries. As Thailand has been undergoing rapid economic transition over the previous decade, we conducted an analysis to demonstrate the secular changes of growth over five years follow-up. Subjects were a cohort of 2,252 primary school children recruited in 1992 for the Hat Yai childhood obesity study. Baseline demographic and family data were collected by a questionnaire completed by parents. To quantify the cohort effect, a generalized estimating equations analysis for a cross sectional time series data was undertaken with weight, height, and body mass index (BMI, kg/m2) as a dependent variable and containing a quadratic term of age, sex, year of birth and family variables. One thousand and ninety-four (48.5%) children completed 6 anthropometric measurements. Graphs of median weight, height, BMI and overweight prevalence of each birth cohort against age showed secular increases of growth and overweight, and an age effect. For each one-year younger cohort, the median weight, median height and median BMI increased by 1.22 kg, 1.25 cm and 0.23 kg/m2, respectively. An increasing trend of childhood overweight reported here may signify a need for preventing overweight and reducing weight in childhood adolescence in the future.

Increasing obesity in school children in a transitional society and the effect of the weight control program.

Childhood obesity is an increasing problem in developed countries. Its persistence into adulthood with accompanied health risks has raised many concerns. In a country with rapid growing economy and changing life styles such as Thailand, the natural history of obesity in school children aged 6-12 years was investigated. Yearly weight and height measurements were performed from 1991 onwards. Of 1,156 primary school children enrolled in 1991, two year follow-up was possible in 1,106 cases. Prevalence of obesity, as diagnosed by weight-for-height > 120% of the Bangkok reference, rose from 12.2% in 1991 to 13.5% in 1992 and 15.6% in 1993. In two years, 74 non-obese children became obese while 28 obese children showed the opposite trend. For those obese children who attended the weight control program, their body mass indices and triceps skinfold thickness increased significantly less than those of the non-attendees in the first year. These findings persisted in the second year but were of a smaller magnitude. Results of this study demonstrate the trend of increasing obesity in school children in the transitional society and the short term benefit of a weight control program.

Breast-feeding and infant growth in the first six months.

Weight and length of 67 breast-fed infants were followed every two weeks from birth to 6 months. All infants were healthy and developed normally. Weight curves were found to be parallel to the NCHS and Bangkok curves up to 4 months then bending slightly but not statistically significant. This supports "the breast-fed infants having a different growth pattern from the mixed (breast-formula) fed" finding observed in studies from developed countries. In comparison to the NCHS and Bangkok length data, rural male infants were significantly (p less than 0.01 and 0.05 respectively) shorter from birth onwards, whereas, median lengths of the rural female infants were significantly shorter (p less than 0.01 and 0.05 respectively) after 4 months. Genetic influence on linear growth was thought to be the cause. The cautious use of the current growth curves on breast-fed infants was emphasized.