Waist circumference percentile curves for Malaysian children and adolescents aged 6.0-16.9 years

Background. The prevalence of obesity is increasing rapidly and abdominal obesity especially is known to be a risk factor for metabolic syndrome and other non-communicable diseases. Waist circumference percentile curves are useful tools which can help to identify abdominal obesity among the childhood and adolescent populations. Objective. To develop age- and sex-specific waist circumference (WC) percentile curves for multi-ethnic Malaysian children and adolescents aged 6.0-16.9 years. Subjects and methods. A total of 16,203 participants comprising 8,093 boys and 8,110 girls recruited from all regions of Malaysia were involved in this study. Height, weight, WC were measured and BMI calculated. Smoothed WC percentile curves and values for the 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th and 97th percentiles were constructed using the LMS Method. Results. WC was found to increase with age in both sexes, but boys had higher WC values at every age and percentile. Z-scores generated using the UK reference data shows that Chinese children had the highest WC compared to Malays, Indians and other ethnicities. Comparisons with other studies indicate that at the 50th percentile, Malaysian curves did not differ from the UK, Hong Kong and Turkish curves, but at the 90th percentile, Malaysian curves were higher compared with other countries, starting at 10 years of age. The 90th percentile was adopted as the cut-off point to indicate abdominal obesity in Malaysian children and adolescents. Conclusion. These curves represent the first WC percentiles reported for Malaysian children, and they can serve as a reference for future studies.