Neurodevelopment of low birth weight born infants in relation to their iron status in Dar es salaam, Tanzania

Abstract

ABSTRACT Background: Iron plays an essential role in many important biochemical processes. As with all nutrients, the requirement for iron is greater during periods of rapid growth and differentiation such as in the late fetal and neonatal period. Poor iron homeostasis during this period can result in disordered development. Inadequate tissue iron levels can lead to reduced erythropoiesis and poor oxygen carrying capacity. The nervous system, which develops rapidly during the late fetal and early neonatal period, seems to be particularly susceptible to iron deficiency. Objective: To assess neurodevelopment of low birth weight infants in relation to their iron status. Methodology Hospital based descriptive cross-sectional study of 270 infants who were born premature/low birth weight aged less than 12 months, attending the high-risk children clinic, whose mothers consented. Infants were recruited on Mondays and Fridays during their clinic visit using convenient sampling technique. Infants with known congenital anomalies, born with birth asphyxia, meningitis and jaundice and those who were acutely ill during the clinic visit were excluded from the study. Bayley Mental Developmental Scoring was done on all infants recruited in the study, along with a thorough history, physical examination and laboratory tests including serum ferritin and complete blood count. Cognitive, motor and language development scores were considered normal with score of ≥85 and poor with score of <85. Iron deficiency were considered if serum ferritin was <12µ/dl. Results Of the 270 infants, 124 (45.9%) were male and 146 (54.1%) were female providing a male to female ratio of 0.8:1. The prevalence of poor cognitive, motor and language development were 90%, 88.2% and 59.2% respectively. Poor cognitive, language and motor development were noted with vii increasing age with p=0.0001 in all categories. Language and motor development were more poorly developed in females than males with p=0.05 and p= 0.006 respectively. Infants with iron deficiency and poor cognitive percentile score were 37% compared with 18% of iron deficient infants with normal cognitive percentile scores (p=0.007). More infants with poor language percentile scores (35%) were observed in iron deficient infants than iron sufficient infants (p=0.04). Motor development percentile score was not significantly affected among the iron deficient infants Infants with a history of not receiving iron supplementation had poor cognitive, language and motor development with p=0.006, 0.001, and 0.0001 respectively. The prevalence of iron deficiency was 34.1%. The iron status of the baby was significantly associated with the gestational age (p=0.0004), the birth weight (p=0.0013) and the nutrition status of the infant (p=0.013). Whereas maternal age, gestation age and maternal education were not significantly associated with poor neurodevelopment outcomes, birth weight, nutritional status and iron supplementation status were significantly associated with neurodevelopment. Infants born with very low birth weight of 0.8-1.49kg were significantly associated with poor cognitive development. However, wasting was a positive predictor of poor motor development and not predictive of the status of cognitive and language development. Conclusion and Recommendations Neurodevelopment was poor among infants born with low birth weight and was more pronounced among iron deficient infants. Neurodevelopment was significantly associated with birth weight, iron deficiency and wasting. Therefore the study recommends early neurodevelopment assessment done on all preterm/low birth weight infants to identify neurologically challenged infants and to direct them for further stimulation and supplementation, in order to improve neurodevelopment. viii The study also recommends an improvement in iron supplementation program through universal iron supplementation in the right doses and appropriate duration to all low birth weight infants as well as exploring for other causes of poor neurodevelopment and intervening as needed.