Prevalence of iron deficiency anemia in Brazilian women of childbearing age: a systematic review with meta-analysis

BACKGROUND: Iron deficiency anemia (IDA) is among the most common micronutrient deficiencies in women of childbearing age and may affect children’s development. Brazil has several national programs to tackle this condition, such as food fortification and supplementation for pregnant women, but IDA prevalence in this population has not been systematically reviewed. We sought to determine the prevalence of IDA in Brazilian women of childbearing age through a systematic review with metanalysis. METHODOLOGY: A protocol was previously published on the PROSPERO platform under the code CRD42020200960. A panel of the National Council for Scientific and Technological Development (CNPq) approved the protocol of this study under the public call number 26/2019. The main databases searched were MEDLINE, Web of Science, Scopus, Lilacs, and SciELO. In gray literature, the Brazilian Digital Library of Theses and Dissertations and the annals of the Brazilian Congress of Epidemiology and the Brazilian Congress of Public Health were accessed. The search strategy involved terms related to the condition (IDA) and the age group of the population of interest (teenagers and adults). Studies that had assessed the prevalence of IDA in Brazilian women of childbearing age (10–49 years) were included. Three independent reviewers read all titles and abstracts and extracted data from the included studies. Random effects meta-analyses using the Freeman-Tukey arcsine transformation were carried out with prevalence data, and meta-regression was conducted to test for subgroup differences. The quality of the studies was assessed using the Newcastle-Ottawa Scale. RESULTS: From 21,210 unique records screened, 237 full-texts were retrieved, of which 91 were included in the qualitative synthesis, and 83 were included in the meta-analysis. The overall IDA prevalence was 25% (95% CI [23–28], 83 studies). The subgroup of studies that used random sampling showed a prevalence of 22% (95% CI [17–27], 22 studies), whereas in those with non-random sampling, the prevalence was 27% (95% CI [23–30], 61 studies), without significant differences between subgroups in the metaregression (P = 0.13). High prevalence of IDA were found in the subgroups of studies conducted in the North and Northeast regions (30%; 95% CI [24–37]; seven studies, and 30%; 95% CI [26–34]; 27 studies, respectively), in studies conducted with indigenous population (53%; 95% CI [27–78], four studies), and with studies that had their collections after 2015 (28%; 95% CI [23–34], nine studies). CONCLUSIONS: IDA in women of childbearing age remains a public health problem in Brazil, especially in the North and Northeast region. The national programs should be strengthened and more thoroughly supervised to decrease this condition nationally.