Initiating BMI prevalence studies in Vietnamese children: changes in a transitional economy.

BACKGROUND Rapid changes in dietary patterns and lifestyles in Vietnam warrant monitoring trends of weight, height and body mass index (BMI) among children. OBJECTIVE To determine the trends of weight, height and BMI classification of Vietnamese children, 6-15 years of age, from 1992 to 2000 with reference to socioeconomic, urban and rural differences. METHODS Data in the Vietnam Living Standard Survey (1992-1993) and the General Nutrition Survey (2000) were collected from representative samples of children. Body mass index classification was determined using the International Obesity Task Force criteria to calculate the prevalence and trends in each survey, and in a pooled survey analysis. RESULTS Statistically significant increases were seen in children's mean weight, height and BMI between the two surveys: 2.1 kg for weight, 4 cm for height, and 0.28 kg/m2 for BMI. Increases in height were greater in rural than urban areas, and BMI increases were smaller in rural than urban areas. CONCLUSIONS The rising prevalence of children at risk of overweight in urban Vietnam is a concern that must be monitored to guide policy changes. The unchanging prevalence of rural underweight boys requires attention. A national nutrition program to address under- and overweight for children throughout primary school is needed.