Sizes and obesity pattern of South Iranian adolescent females

Abstract

Background : Sizes (height and weight) and obesity (a scaled weight-by-height index) charts of a representative sample of 1743 healthy adolescent females of Shiraz (Southern Iran) aged 11-17 years are presented. Methods : An adjusted weight-for-height was used to define a possible obesity index. Polynomial modelling was used by applying the HRY (Healy, Rasbash, Yang) nonparametric method to estimate age-related smoothed centiles of sizes and obesity. Results : A ponderal index in the form of weight/height 3 represented obesity better than any other index which is logically related to weight/volume and enjoys biological justification. No more than cubic polynomials were needed to fit height-for-age, weight-for-age, obesity-for-age and weight-for-height smoothly. The 10th, 75th and 97th centiles of height and weight of our subjects lie on the 3rd, median and 90th centiles of the NCHS standard, respectively. Obesity pattern increases with age, giving an appropriate index to study obesity of female adolescents. However, weight-for-height chart independent of age range of subjects may serve as an alternative. Conclusion : It is concluded that the ponderal index is an appropriate index to study obesity of adolescent females, and is a simple one that is biologically plausible. However, other indices such as weight-for-height may be considered as an alternative. A local standard for assessing sizes and obesity of adolescent females is recommended for clinical as well as community health purposes in Iran.