Defining anthropometric cut-off levels related to metabolic risk in a group of Sri Lankan children.

BACKGROUND: Body mass index (BMI) is widely used as a measure of adiposity. However, currently used cut-off values are not sensitive in diagnosing obesity in South Asian populations.

AIM: To define BMI and waist circumference (WC), cut-off values representing percentage fat mass (%FM) associated with adverse health outcomes.

SUBJECTS AND METHODS: A cross-sectional descriptive study of 285 5-14 year old Sri Lankan children (56% boys) was carried out. Fat mass (FM) was assessed using the isotope (D(2)O) dilution technique based on 2C body composition model. BMI and WC cut-off values were defined based on %FM associated with adverse health outcomes.

RESULTS: Sri Lankan children had a low fat free mass index (FFMI) and a high fat mass index (FMI). Individuals with the same BMI had %FM distributed over a wide range. Lean body tissue grew very little with advancing age and weight gain was mainly due to increases in body fat. BMI corresponding to 25% in males and 35% in females at 18 years was 19.2 kg/m(2) and 19.7 kg/m(2), respectively. WC cut-off values for males and females were 68.4 cm and 70.4 cm, respectively.

CONCLUSION: This chart analysis clearly confirms that Sri Lankan children have a high %FM from a young age. With age, more changes occur in FM than in fat free mass (FFM). Although the newly defined BMI and WC cut-off values appear to be quite low, they are comparable to some recent data obtained in similar populations.