Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis
| Autor: | Thilinie Rajapakse, Gilaad G. Kaplan, Tamara Pringsheim, Christine St. Germaine-Smith, Kirsten M. Fiest, Alexandra D. Frolkis, Amy Metcalfe, Nathalie Jette, Callie Atta |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
congenital hereditary and neonatal diseases and abnormalities medicine.medical_specialty Pediatrics Population MEDLINE Prevalence AJPH Research 030105 genetics & heredity Global Health 03 medical and health sciences Folic Acid Pregnancy Environmental health Epidemiology medicine Global health Humans Neural Tube Defects education Spinal Dysraphism education.field_of_study business.industry Spina bifida Public Health Environmental and Occupational Health medicine.disease Europe Meta-analysis Vitamin B Complex Food Fortified Female AJPH Editorials business |
| Zdroj: | Am J Public Health |
| ISSN: | 1541-0048 0090-0036 |
| DOI: | 10.2105/ajph.2015.302902a |
| Popis: | Background. Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region’s food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation. Objectives. We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population. Search methods. An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts. Selection criteria. Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party. Data collection and analysis. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as “mandatory” or “voluntary” folic acid fortification according to each country’s folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food Fortification Initiative). We determined study quality on the basis of sample representativeness, standardization of data collection and birth defect assessment, and statistical analyses. We analyzed study-level period prevalence estimates by using a random effects model (α level of Results. Of 4078 studies identified, we included 179 studies in the systematic review and 123 in a meta-analysis. In studies of live births (LBs) alone, period prevalences of spina bifida were (1) lower in geographical regions with mandatory (33.86 per 100 000 LBs) versus voluntary (48.35 per 100 000 LBs) folic acid fortification, and (2) lower in studies of LBs, stillbirths, and terminations of pregnancy in regions with mandatory (35.22 per 100 000 LBs) versus voluntary (52.29 per 100 000 LBs) fortification. In LBs, stillbirths, and terminations of pregnancy studies, the lowest pooled prevalence estimate was in North America (38.70 per 100 000). Case ascertainment, surveillance methods, and reporting varied across these population-based studies. Conclusions. Mandatory legislation enforcing folic acid fortification of the food supply lags behind the evidence, particularly in Asian and European countries. This extensive literature review shows that spina bifida is significantly more common in world regions without government legislation regulating full-coverage folic acid fortification of the food supply (i.e., Asia, Europe) and that mandatory folic acid fortification resulted in a lower prevalence of spina bifida regardless of the type of birth cohort. African data were scarce, but needed, as many African nations are beginning to adopt folic acid legislation. |
| Databáze: | OpenAIRE |
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