Longitudinal pattern and reference values of obesity indices of infants in Jahrom [southern region of], Iran

ABSTRACT

Obesity [scaled weight-by-height index] charts of a cohort of 597 healthy infants [391 boys and 206 girls] living in Jahrom [Southern Iran] are presented. An adjusted weight-for-height was used to develop power type obesity indices, Ip=W/Hp. Polynomial modeling was used by applying HRY [Healy, Rasbash, Yang] nonparametric method to estimate age-related smoothed centiles of obesity. The optimal value of p was found to be 2.5 for girls and 2 for boys. No more than cubic and quadratic polynomials were needed to fit obesity-for-age smoothly for infants. Infant's obesity increases from birth to six months of age and decreases later on to the age of 20 months when it becomes stable. Using age-dependent obesity index [scaled weight by height] is an appropriate index which explores the degree of fatness. A local standard for assessing obesity in clinical practice as well as community health programs in Iran is of urgent need; our data serve this purpose: