Prevalence Of Vitamin B Complex Deficiencies In Women In Reproductive Age, Pregnant Or Lactating Woman In Brazil: A Systematic Review And Meta-Analysis Protocol

Abstract Background: Complex B vitamin deficiency are involved with several outcomes in fertility and pregnancy. In Brazil, the national prevalence rates of these micronutrients deficiencies in women at reproductive age was not known. Therefore, this study aims to systematically identify, select, evaluate, analyze and report the prevalence rates of complex B vitamins deficiencies in women at reproductive age in Brazil, and identify variables that may modify the outcome rates.Methods: A systematic review will be conducted guided by the following question: “What is the prevalence of vitamin B complex deficiencies in women at reproductive age in Brazil?”. The studies will be identified and selected from a literature search using electronic databases, consultation to researchers/specialists, as well as reference lists of eligible studies and reviews on the topic. Major eligibility criteria include observational cross-sectional and cohort studies performed in women with 10-49 years old from Brazil; pregnant and lactating mothers; and which that investigated the deficiency of complex B vitamins by laboratorial test. Two reviewers independently will perform the screening and selection of studies, to subsequently perform data extraction and risk assessment of bias. For data report, a narrative approach will be used to summarize the characteristics of the included studies and the individual prevalence found for each micronutrient tested, and if the studies are sufficiently homogeneous, a quantitative synthesis (meta-analysis) will be performed.Discussion: Identify the national and regional prevalence rates of complex B vitamins deficiencies allow the policy makers discuss, plan and implement public policy to prevent and/or reduces the rates, if they are larger, or at least highlight discussions about a program of screening the vitamins deficiencies in this specific population for to know the epidemiologic scenario among the years, serving as an indirect indicator of the socioeconomic and dietary patterns of this population. Also, specifically for folates, this study allows to compare the prevalence rates of deficiency of this vitamin before and after the mandatory fortification of wheat and corn flours implemented since 2004. Nevertheless, the evidence gathered may highlight the need for population-based studies to investigate the deficiency of these vitamins.Systematic review registration: PROSPERO registration number: CRD42020188474