Height-adjusted percentiles evaluated central obesity in children and adolescents more effectively than just waist circumference

Aim: We compared the prevalence of obesity based on both waist circumference for height and body mass index (BMI) in Iranian children and adolescents. Methods: Data on 13 120 children with a mean age of 12.45 +/- 3.36 years (50.8% male) from the fourth Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable Disease study were included. Measured waist circumference values were modelled according to age, gender and height percentiles. The prevalence of obesity was estimated using the 90th percentiles for both unadjusted and height-adjusted waist circumferences and compared with the World Health Organization BMI cut-offs. They were analysed further for short, average and tall children. Results: Waist circumference values increased steadily with age. For short and average height children, the prevalence of obesity was higher when height-adjusted waist circumference was used. For taller children, the prevalence of obesity using height-adjusted waist circumference and BMI was similar, but lower than the prevalence based on measurements unadjusted for height. Height-adjusted waist circumference and BMI identified different children as having obesity, with overlaps of 69.47% for boys and 68.42% for girls. Conclusion: Just using waist circumference underestimated obesity in some Iranian children and measurements should be adjusted for height.