Birth prevalence of neural tube defects in eastern Africa: a systematic review and meta-analysis

Neural tube defects (NTDs) are associated with high rates of neonatal mortality and morbidity worldwide. The promotion of folic acid fortification and supplementation in pregnant women by the Food and Drug Administration significantly decreased the incidence of NTDs in the United States. This practice is not widely adopted in Eastern Africa countries. We hypothesized that these countries experience a higher burden of NTDs than countries that promote the use of folic acid. We aimed to estimate the birth prevalence of NTDs in the United Nations (UN) Eastern African region.

PubMed (Medline), Embase, and Cochrane Library databases were systematically searched from inception to December 17, 2021. We included randomized controlled trials or observational studies that reported the prevalence estimates of NTDs in Eastern Africa. Random effects model was used to pool the effect estimates. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess the certainty of the evidence. Outcome measures were overall and specific (spina bifida, anencephaly, encephalocele) rates of NTDs per 10,000 births, including live and stillborn cases.

The meta-analysis included 20 studies consisting of 752,936 individuals. The pooled prevalence of all NTDs per 10,000 births in Eastern Africa was 33.30 (95% CI: 21.58 to 51.34). Between-study heterogeneity was high (I² = 97%, p < 0.0001), The rate was highest in Ethiopia (60 per 10,000). Birth prevalence of spina bifida (20 per 10,000) was higher than anencephaly (9 per 10,000) and encephalocele (2.33 per 10,000). No studies on NTDs were identified in 70% of the UN Eastern Africa region. Birth prevalence increased by 4% per year from 1983 to 2018. The level of evidence as qualified with GRADE was moderate.

The birth prevalence of NTDs in the United Nations region of Eastern Africa is 5 times as high as observed in Western countries with mandatory folic acid supplementation in place. Therefore, mandatory folic acid supplementation of stable foods may decrease the risk of NTDs in Eastern Africa.