Vahid Alinejad - Urmia University of Medical Sciences, Urmia, Iran.
Rasool Gharaaghaji Asl - Urmia University of Medical Sciences, Urmia, Iran.

Objectives: Growth trajectory standards are important components to monitor for suitable child growth. This study investigated longitudinal data to identify factors affecting growth trajectory of infants for height and weight.Methods: This study includes ۳۱۰ neonates (۱۶۲ boys and ۱۴۸ girls) born in West Azerbaijan Province, northwest of Iran, and followed from birth for ۴ years. Weights and heights of the subjects were recorded at birth, one, two, four, six, nine months and ۱, ۱.۵, ۲, ۳ and ۴ years of age. In this study LMS method was utilized to construct growth curves for each measure. The linear mixed model was applied to determine factors affecting the growth trajectory.Results: The study shows birth region, breast feeding duration and infants’ gender had a significant effect on growth trajectory. However, other variables had not any significant effect on growth. Growth curves for significant factors of weight and height (۵th, ۵۰th, ۹۵th percentiles) were obtained. The growth charts increased rapidly from birth to ۲ years of old and then remained relatively constant up to ۴ years.Conclusions: The paper provided the first local growth trajectory standards of height and weight for infants by analyzing longitudinal measurements produced for West Azerbaijan province. Study determines effective factors on growth trend in both indices. It seems that there is significant difference between the growth trajectories of infants in subgroups of effective factor.

Growth curve, infant, weight, height, LMS method.