Child Weight Growth Trajectory and its Determinants in a Sample of Iranian Children from Birth until 2 Years of Age.
BACKGROUND
Growth is one of the most important indices in child health. The best and most effective way to investigate child health is measuring the physical growth indices such as weight, height and head circumference. Among these measures, weight growth is the simplest and the most effective way to determine child growth status. Weight trend at a given age is the result of cumulative growth experience, whereas growth velocity represents what is happening at the time.


METHODS
This longitudinal study was conducted among 606 children repeatedly measured from birth until 2 years of age. We used linear mixed model to analyze repeated measures and to determine factors affecting the growth trajectory. LOWESS smooth curve was used to draw velocity curves.


RESULTS
Gender, child rank, birth status and feeding mode had a significant effect on weight trajectory. Boys had higher weight during the study. Infants with exclusive breast feeding had higher weight than other infants. Boys had higher growth velocity up to age 6 month. Breast fed infants had higher growth velocity up to 6 month, but thereafter the velocity was higher in other infants.


CONCLUSIONS
Many of the studies have investigated child growth, but most of them used cross-sectional design. In this study, we used longitudinal method to determine effective factors on weight trend in children from birth until 2-year-old. The effects of perinatal factors on further growth should be considered for prevention of growth disorders and their late complications.
Department of Bio-statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Sayed-Mohsen
SM
Hosseini
Department of Bio-statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Mohamad-Reza
MR
Maracy
Department of Bio-statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Sheida
S
Sarrafzade
Department of Pediatrics, Faculty of Medicine and Child Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Roya
R
Kelishadi
Growth; linear mixed model; velocity; weight