Epidmiology and Effct on Birtweight of Prenatal Zinc and Vitamin a Deficiencies in Rural Sidama Southern Ethiopia
Creators: name: Gebremedhin, Samson
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2012

description: Background: In the developing world pregnant women face diverse nutritional deficiencies with potentially grave consequences. The most prevalent deficiencies are assumed to be Protein Energy Malnutrition (PEM), Iron Deficiency Anemia (IDA), Vitamin A (VA) Deficiency (D), Iodine Deficiency Disorders (IDD) and Zinc Deficiency (ZD). Nevertheless, currently limited information is available about the prevalence of prenatal zinc and vitamin A deficiencies in Ethiopia. Previous studies which attempted to identify the correlates of the deficiencies and their effects on birthweight ended up in equivocal conclusions. Objective: To assess the prevalence, correlates and effect on birthweight of prenatal ZD and VAD in rural Sidama, Southern Ethiopia. Methods: The study included a community based cross-sectional baseline study to assess the prevalence and correlates of the deficiencies and a prospective cohort study to evaluate the effects of the deficiencies on birthweight. The baseline study was conducted in January 2011 among 700 randomly selected pregnant women. Data on potential correlates of the deficiencies were gathered using a structured questionnaire. Serum zinc, retinol, ferritin, hemoglobin and C - Reactive Protein (CRP) concentrations were determined from venous blood following standard procedures. In the cohort study 575 pregnant women who were in their second or third trimester during the baseline survey were successfully followed until delivery and birthweight was measured within 72 hours of birth. Data were analyzed using linear, logistic and log-binomial regression models. The dissertation also incorporated a meta-analysis of Randomized Control Trials (RCTs) so as to assess the effect of prenatal zinc supplementation on birthweight. Relevant studies were identified through web-based search. Effect Size (ES) was measured based on standardized mean difference and pooled using a variant of random effect model. xii Results: About 53.0%, 37.9% and 17.4% of the subjects had ZD, VAD and Iron Deficiency (ID). Taking the three deficiencies into consideration, 32.9% of the subjects had two or more concomitant deficiencies and 5.1% had three of the deficiencies. Elevated CRP and gestational age were significant negative correlates of zinc status. ZD was substantially higher among pregnant women from food insecured households and amongst those who had low Dietary Diversity Score (DDS) in the preceding day of the survey. Illiterates and women devoid of self income had 1.71 (95% CI: 1.09-2.60) and 1.74 (95% CI: 1.11-2.74) times increased risk of ZD. The risk was also 1.65 (95% CI: 1.02-2.67) times higher among women from maize staple diet category compared to Enset. Women aged 25-34 and 35-49 years were 1.57 (95% CI: 1.04-2.34) and 2.18 (95% CI: 1.25-3.63) times more likely to be deficient than those aged 15-24 years. Grand multiparas were 1.74 (95% CI: 1.09-3.23) times at risk than nulliparas. Frequency of coffee intake was negatively associated to zinc status. Positive association was noted between serum zinc and hemoglobin concentrations. Elevated CRP was associated with 22.5% reduction in serum retinol concentration. Women at their third trimester had 2.59 (95% CI: 1.23-5.48) times increased risk of VAD compared to those at the first trimester. The risk of VAD was significantly higher among illiterates and women without their own income. Women aged 35-49 years had 2.23 (95% CI: 1.31-3.81) times higher risk compared to those aged 15-24 years. Women with low DDS were 1.94 (95% CI: 1.17-3.19) times more likely to be deficient than their counterparts with high DDS. Compared to nulliparas, multiparas had 2.25 (95% CI: 1.20-4.22) times increased risk of VAD. VAD and ZD were associated to each other with adjusted OR of 1.80 (95% CI: 1.28-2.53). The mean birthweight among babies born to women who were at their second or third trimester at the time of exposure assessment was 2896 g and 16.5% (95 % CI: 13.5-19.6%) had LBW. Prenatal ZD and VAD were not significantly associated to LBW with Adjusted Relative Risk (ARR) of 1.25 (95 CI: 0.86-1.82) and 1.27 (95% CI: 0.86-1.87), respectively. The occurrences of ZD and VAD, neither in the second nor third trimester, were associated to LBW. The deficiencies did not show synergetic interaction in causing LBW with SI of 1.04 (95% CI: 0.17- 6.28). Significant determinants of LBW were maternal illiteracy, maternal thinness and stunting, primiparity, female sex of the baby and elevated CRP during pregnancy. xiii Among 17 RCTs included in the meta-analysis, 3 reported positive association between zinc supplementation and birthweight, 1 had marginally negative association where as 13 found no association. Based on DerSimonian and Laird's random effect model, the pooled ES was 0.071 (95% CI: 0.162 to -0.019) and it remained insignificant after stratification was made based on the dose of supplementation (optimal or high dose), design of the studies (community or health institution-based), and development status of the study country (developed or developing). Conclusion: ZD and VAD are of public health concern in the area. Key correlates of ZD were household food insecurity, low DDS, dependency on maize as a staple diet and low level of consumption of animal source foods. Illiterates and women devoid of self income had increased risk of ZD. Grand multiparity, old age pregnancy and frequent consumption of coffee were negative correlates. Pertaining to VAD, advanced gestational age elevated CRP were negatively associated with serum retinol level. Advanced maternal age, inferior socio-economic status, dependence on poorly diversified and plant based diet, ZD and history of too close and too many births were pertinent correlates of VAD. Prenatal ZD and VAD occurring neither in the second nor third trimester were not associated to LBW. Further, the deficiencies did not show synergetic interaction in causing LBW. Based on the meta-analysis, prenatal zinc supplementation did not show positive effect on birthweight. Recommendation: Zinc and VA deficiencies should be combated through food-based approach as it is a sustainable strategy to prevent multiple micronutrient deficiencies. Approaches that focus on dietary diversification like backyard gardening and poultry production should be promoted. The existing efforts to improve women's awareness about optimal nutrition prior and during pregnancy should be strengthened through building the capacity of health extension workers and voluntary community health promoters. Strong intersectoral collaboration must be established between the health and agriculture sectors so as to address the root causes of malnutrition. Use of household based phytate reduction techniques, utilization of zinc containing fertilizers should be considered as potential strategies to combat ZD. Expansion of family planning coverage, livelihood promotion and socio-economic empowerment of women shall have affirmative influence. Key Words: Prenatal zinc deficiency, prenatal vitamin A deficiency, low birthweight.