Describing the Prevalence of Neural Tube Defects Worldwide: A Systematic Literature Review

Abstract

BackgroundFolate-sensitive neural tube defects (NTDs) are an important, preventable cause of morbidity and mortality worldwide. There is a need to describe the current global burden of NTDs and identify gaps in available NTD data.Methods and FindingsWe conducted a systematic review and searched multiple databases for NTD prevalence estimates and abstracted data from peer-reviewed literature, birth defects surveillance registries, and reports published between January 1990 and July 2014 that had greater than 5,000 births and were not solely based on mortality data. We classified countries according to World Health Organization (WHO) regions and World Bank income classifications. The initial search yielded 11,614 results; after systematic review we identified 160 full text manuscripts and reports that met the inclusion criteria. Data came from 75 countries. Coverage by WHO region varied in completeness (i.e., % of countries reporting) as follows: African (17%), Eastern Mediterranean (57%), European (49%), Americas (43%), South-East Asian (36%), and Western Pacific (33%). The reported NTD prevalence ranges and medians for each region were: African (5.2–75.4; 11.7 per 10,000 births), Eastern Mediterranean (2.1–124.1; 21.9 per 10,000 births), European (1.3–35.9; 9.0 per 10,000 births), Americas (3.3–27.9; 11.5 per 10,000 births), South-East Asian (1.9–66.2; 15.8 per 10,000 births), and Western Pacific (0.3–199.4; 6.9 per 10,000 births). The presence of a registry or surveillance system for NTDs increased with country income level: low income (0%), lower-middle income (25%), upper-middle income (70%), and high income (91%).ConclusionsMany WHO member states (120/194) did not have any data on NTD prevalence. Where data are collected, prevalence estimates vary widely. These findings highlight the need for greater NTD surveillance efforts, especially in lower-income countries. NTDs are an important public health problem that can be prevented with folic acid supplementation and fortification of staple foods.

Factors associated with folic acid knowledge and intake among pregnant women in Sudan

“…This percentage is comparable to the rate in Qatar (8.7%) (23), but lower than rates in Saudi Arabia (15) and the United Arab Emirates (24), 11.2% and 14% respectively. In our study, lack of knowledge and less preconception use of folic acid may explain the high rate of neural tube defects prevalence (12.5/10 000 births) in our setting (25),compared with rates of 2/10 000, 3.3/10 000, and 0.4/10 000 births reported from Egypt, Nigeria and Saudi Arabia respectively (25).…”

“…Also, our study showed a significant association between preconception use of folic acid and living in urban areas, being booked, a higher level of education and antenatal care attendance. On the other hand, some studies failed to demonstrate any association between sociodemographic characteristics and folic acid use (25).…”

The Prevalence, Trend, and Associated Demographic Factors of Neural Tube Defects at Orotta National Referral Maternity Hospital, Asmara: Retrospective Record Review Study

“…This high prevalence can be argued that as in Eritrea, even though there is folic acid supplementation, it is only during pregnancy as well as absence of folic acid fortification on foods can lead to this high prevalence of NTD [8]. This high result is similar to most developing world, where folic acid supplementation and prenatal counseling was not practiced [9,10]. The result of the study showed anencephaly as the most common NTD.…”

Folic and Folate Acid

“…The reported NTD prevalence ranges and medians for each region were: Africa (5.2-75.4; 11.7 per 10,000 births), Eastern Mediterranean (2.1-124.1; 21.9 per 10,000 births), Europe (1.3-35.9; 9.0 per 10,000 births), Americas (3.3-27.9; 11.5 per 10,000 births), South-East Asia (1.9-66.2; 15.8 per 10,000 births), and Western Pacific (0.3-199.4; 6.9 per 10,000 births) [42]. According to the Morbidity and Mortality Weekly Report, if 50-70% of NTDs can be prevented by consuming 400 µg of folic acid per day, assuming a prevalence of 300,000 NTDs per year, worldwide folic acid fortification could prevent 150,000-210,000 NTDs annually [35].…”