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

Abstract

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 (D₂O) 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/m² and 19.7 kg/m², 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.

Keywords::

• BMI cut-off
• fat mass
• Hattori chart
• Sri Lankan children
• waist circumference cut-off

Acknowledgements

We are grateful to all subjects and their parents for participating in this study. Dr Samanmali Sumanasena is thanked for providing assistance in the collection of data.

Declaration of interest: This study was carried out with financial support from Children's Nutrition Research Centre, Department of Paediatrics and Child Health, University of Queensland, Brisbane, Australia. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.