Changes in adiposity indicators of Ho Chi Minh City adolescents in a 5-year prospective cohort study

OBJECTIVE: The aim of this study was to examine changes over 5 years in body mass index (BMI) and waist circumference (WC) of adolescents from Ho Chi Minh City by age, gender and household economic status. METHODS: Anthropometry including height, weight and WC measurements of 759 secondary high school students were collected 1-year apart in a prospective cohort study, between 2004 and 2009. BMI was calculated and overweight/obesity was defined using International Obesity Task Force (IOTF) BMI cutoffs. Abdominal 'overweight' and 'obesity' were defined as WC > 91st-97th and >= 98th centile, respectively. BMI z-scores were also created. RESULTS: Over the 5-year period, the absolute changes in mean BMI and WC were statistically significant (P<0.001). Boys had higher BMI and WC values than girls (P<0.001). The prevalence of overweight and obesity defined by IOTF BMI cutoff values increased gradually from 12.5% and 1.7% in the first year to 16.7% and 5.1% in the last year. Using WC cutoff values, the prevalence of abdominal overweight and obesity increased from 12.9% and 1.8% to 18.5% and 6.6%, respectively. BMI z-score curves shifted towards the right-hand side of the distribution (that is, towards overweight and obesity). CONCLUSION: Overweight and obesity, as measured by BMI or WC, continued to increase among adolescents of Ho Chi Minh City over the 5-year period.