Longitudinal Pattern and Reference Values of Obesity Indices of Infants in Jahrom (Southern Region of), Iran

Objective: 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.
Material & Methods: An adjusted weight-for-height was used to develop power type obesity indices, I_p=W/H^p. Polynomial modeling was used by applying HRY (Healy, Rasbash, Yang) nonparametric method to estimate age-related smoothed centiles of obesity.
Findings: 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.
Conclusion: 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.