In this study, we found that the prevalence of stunting was 3.7%. Birth weight, fathers’ height and maternal age were the main contributing factors to stunting in the studied population.
The prevalence of stunting in this study was in agreement with the one reported by National Study of Malnutrition Prevalence in Iranian children. It seems that the prevalence of stunting has been decreased in the past decade in the country. The decreasing trend of stunting has been reported in South East Asia, where the stunting has reduced in elementary school children from 52.4%in 1998 to 32.8% in 2000.[27
] Worldwide stunting prevalence has also decreased from 48.8% in 1980 to 39.9% in 1995.[28
] This can be explained by improved primary health care during pregnancy and early childhood, breastfeeding and growth monitoring.
In this study, the prevalence of low birth weight and short duration of breastfeeding (<6 mo) was higher in cases than that in controls. The same findings have been reached by Lwambo et al
] Marshall et al
] and Ricci et al
] Low birth weight infants have inadequate nutrient stores required for height growth. Due to increased requirements in these infants, additional amounts of nutrients are needed for these babies to reach normal height growth.[32
] Findings of the current study about breastfeeding are in agreement with those of Marquis et al
., in Peru[33
] and Semba et al
., in Indonesia and Bangladesh which indicated that short duration of breastfeeding was positively related to prevalence of stunting. Short duration of breastfeeding would prohibit adequate dietary intakes of energy, protein and micronutrients required for normal height growth.[34
Low birth weight was found as a contributing factor to stunting in this study. This finding is in line with earlier studies among Brazilian,[35
] and Pakistani children.[37
] Birth weight has also been reported as a strong predictor of child size in later life among children with Intra-Uterine Growth Retardation (IUGR). Most IUGR infants do not catch-up to normal size during childhood. Low birth weight and subsequent stunting could be induced by maternal under-nutrition during pregnancy. In the current study, we did not collect data about dietary intakes of mothers during their pregnancy. Adequate nutrition during pregnancy would result in increased birth weight and in turn would improve child growth in later life.
Another determinant of stunting in the current study was maternal age. This finding is in agreement with previously reported ones. In Egypt, children born to mothers aged ≥35 years showed a higher prevalence of stunting than children born to mothers in other age groups.[15
] Maternal age has also been reported as a determinant factor of stunting in South African children.[38
] The effect of the age of the mother on child health outcomes has also been explored in several studies.[39
] In the case of India, Raj et al
., showed that children born to mothers who were married below the age of 18 were at a higher risk of stunting and underweight compared to children of women who had married at age 18 or older. Although, several studies have reported the importance of mothers’ young age at pregnancy on health outcomes of children, limited data have focused on older age. The current findings highlight the importance of old age of mothers as a contributing factor to stunting.[41
As we all know socioeconomic status and dietary intakes are two important contributing factors to stunting.[42
] We tried to collect data on economical status of the households; however, after completion of the study, we found that these data are not reliable. So, we used educational status of parents as a proxy of socioeconomic status. One might suggest the use of living district as a proxy of socioeconomic status. In the current study, when we explored the frequency of stunting in different districts of Tehran (5 districts were selected in this study), we failed to find a significant difference. Due to the inclusion of children from different socioeconomic status in the current study, the findings can easily be extrapolated to the Tehrani children, however, more caution are required about the generalizability of the findings to the whole country.