Relationship between infant birth weight < 2000gms. And maternal ZINC levels at Muhimbili National Hospital, Dar es Salaam, Tanzania.

The incidence of low birth Weight (LBW) in Tanzania is among the highest in the world. It accounts for more than 16% of all deliveries. Despite efforts by the Ministry of health (MOH) using different intervention measures to reduce it, there are no improvement as shown by the data of 1979 (15%). 1990 (16%) and on recent estimates of 2000 and 2001 (18%). LBW is a reliable indicator of (risk of death, growth failure, neurodevelopment problems, recurrent infections and hospitalization). There is a need to reduce the incidence of LBW. Maternal zinc deficiency has been noted in a number of settings to impair growth and development of the fetus. In Tanzania, there is little information on zinc deficiency and its effect on birth weight of infants. However, based on dietary intakes of many communities. It is likely that zinc deficiency is a problem. Study objective To determine the relationship between infant birth weight < 2000gms and maternal zinc status. Study design Unmatched case control. Study setting The study was conducted at Muhimbili National Hospital (MNH) in labour ward, from July to September 2002 Study population The study population consisted of infants with birth weight of <2000gms and their mothers as cases and infants with birth weight of > 3000gms and their mothers as cases and controls respectively who consented for the study. Methodology The study used convenient sampling technique. The first mother with an infant weighing <2000gms who consented was recruited as a case and the consenting mother who had a normal birth weight infant was recruited as a control. Subsequently all eligible subjects were recruited until the estimated sample size was reached. Maternal and infants cord blood samples were taken after delivery. Plasma zinc was analyzed using atomic absorption spectrophotometry method. Data were analyzed using epiinf version 6. Logistic regression was used to assess the contribution of other risk factors on infant birth weight. Data were converted to STATA format and logistic regression analysis was done using STATA program version 8. Results The results showed that there is significant relationship between infant birth weight and maternal zinc levels. Mothers with low zinc levels were two and half times more at risk of having an infant weighing <2000gms compared to those with normal zinc level (OR2.62 Cl 1.36-5.73). the association was statistically significant (p value = 0.002). Cord blood zinc concentration was significantly lower in LBW compared to control babies. Infants with low zinc levels were almost three times more at risk of being born with birth weight <2000gms compared to those with normal zinc levels (OR 2.79 Cl 1.36-5.73). The relationship is statistically significant (p value= 0.0016). Conclusions • This case- control study indicated that there is a relationship between low infant birth weight < 2000gms and maternal zinc deficiency. • There is a relationship between infant birth weight and infant zinc level • Maternal age of <19 years is associated with low infant birth weight and low maternal zinc levels. • Plasma zinc levels in mothers correlated with plasma zinc levels in their offspring.

Recommendation • A community based survey is needed to determine if the relationship between maternal zinc and LBW is a public health problem in Tanzania and therefore initiate zinc supplementation.