Iodine deficiency in women of childbearing age in Brazil: systematic review and meta-analysis

Abstract

Background: Despite current policies of salt iodination, iodine deficiency is still a global public health problem, especially in women. So far, conflicting evidence has been suggested for the prevalence of iodine deficiency in Brazil. Objective: To estimate the prevalence of iodine deficiency and associated factors in women of childbearing age in Brazil. Methods: A systematic review was conducted using databases (PubMed, LILACS, WHO, Scopus, and Capes’ dissertation and thesis), from inception to May 2020. Meta-analyses of proportions were performed using the variance inverse for the fixed model. Reporting and methodological quality were assessed using the Joanna Briggs Institute tool to prevalence studies. Results: Our review identified seven studies published between 2002 e 2017, including 1354 participants, especially pregnant women. All studies presented at least one quality limitation, mainly regarding the sampling method (i.e., convenience) and small sample size. The prevalence of iodine deficiency ranged among studies from 16% to 62%. In contrast, the meta-analysis identified a mean prevalence of 40% (95% confidence interval, CI 37%-43%) for pregnant women and 13% (95% CI 4%-24%) for non-pregnant women. Cumulative meta-analysis suggests a tendency of higher iodine deficiency prevalence from 2018 in pregnant women. Conclusions: Although this systematic review identified studies with poor methodological and reporting quality, a high prevalence of iodine deficiency was identified in pregnant women, reinforcing the importance of national nutritional policies for monitoring iodine status in this population. Future studies should consider random probabilistic sampling, appropriate sample size, and pre-defined subgroup analysis to adequately inform the prevalence of iodine deficiency and associated factors in women of childbearing age and support health policies.

Deficiency and Insufficiency of Vitamin D in Women of Childbearing Age: A Systematic Review and Meta-analysis

“…1), and deficiency or insufficiency of 72% (95%CI: 71-74%) (►Appendix A, supplementary material) were obtained. 23 When the population subgroups were considered, lower and higher prevalence of vitamin D deficiency were identified in pregnant (27%) and postpartum women (48%), respectively; and lower and higher prevalence of vitamin D insufficiency were associated with adolescents (37%) and women of childbearing age (50%) (►Fig. 1).…”

“…Sensitivity analyses with alternative statistical methods identified values of prevalence ranging from 35 to 37% for vitamin D deficiency, 41 to 43% for vitamin D insufficiency, and 69 to 72% for vitamin D deficiency or insufficiency (►Appendix A, supplementary material). 23 Abbreviations: CI, confidence interval; GDM, gestational diabetes mellitus; HIV, human immunodeficiency virus; IQR, interquartile range; NR, not reported; RYGB, Roux-en-Y gastric bypass; SD, standard deviation. Notes: A -Pregnant, breastfed, carriers of chronic diseases (diabetes, hypertension, chronic kidney disease), chronic alcoholics, and chronic smokers were excluded.…”

“…The data that support the findings of this study are openly available in OSF at http:doi.org/10.17605/OSF.IO/J9QMH. 23…”

“…It was not possible to conduct sensitivity analyses regarding gestational trimesters.Potential publication biases were not identified in vitamin D deficiency (p ¼ 0.84), insufficiency (p ¼ 0.60), or deficiency or insufficiency (p ¼ 0.54) in statistical or visual analyses (►Appendix E, supplementary material) 23. It was also not…”

The Relationship Between Iodine Status and Thyroid Stimulating Hormone (TSH) and Free T4 (FT4) in Women of Childbearing Age in Wonogiri Regency

“…Because more than 90% of ingested iodine for individuals in positive iodine balance is ultimately excreted in the urine, urinary iodine is an excellent indicator of recent iodine intake. Collecting twenty-four (24) hour urine specimens in field research is impractical. Urinary iodine can be assessed in spot urine specimens from a representative sample of the target population [15,18,19].…”