Update of Growth Percentiles for Children of an Iranian Population

Background – Growth assessment is an essential component of pediatric health surveillance because almost any problem within physiologic, interpersonal, and social domains can adversely affect growth. The growth chart is the most powerful tool in growth assessment. Standard growth charts are based on the data collected by the American National Center for Health Statistics (NCHS).Growth percentiles require periodic revision because of the changes in the ethnic mix of the population as well as socioeconomic and environmental conditions. This paper describes the new reference percentile curves for weight, height, and head circumference in an Iranian population between birth and 6 years of age.Methods – Fifteen-hundred and forty children (808 boys and 732 girls) were studied using cross-sectional method. Based on the primary data, 5 percentiles (5, 25, 50, 75, and 95) were determined for each sex and age group separately. The smoothed curves were then prepared. The smoothed curves of the 50th percentiles in our study compared to those of NCHS. Results – Using Run test, there were no significant differences between the percentiles found in our study and those in NCHS except for three groups: the height of males at birth (p = 0.0268), the weight of females at 18th month (p = 0.0456), and the weight of males at 4 ½ years of age (p = 0.0109). However, after 36th month, Iranian children were found to be generally lighter and smaller than the subjects in NCHS references. Conclusion – The new reference smoothed curves are similar to NCHS curves. The means, NCHS/WHO standards are appropriate for growth assessment in our community in this range of age (0 – 6 years). Nevertheless, for determination of standard growth charts especially for weight and height, more extensive studies on other age groups and in different locations of Iran are recommended.