The prevalence of insufficient iodine intake in pregnancy in Africa: protocol for a systematic review and meta-analysis

Abstract

Background Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal. Systematic review registration PROSPERO CRD42018099434 Electronic supplementary material The online version of this article (10.1186/s13643-019-1092-7) contains supplementary material, which is available to authorized users.

The Prevalence of Insufficient Iodine Intake in Pregnancy in Africa: a Systematic Review and Meta-analysis

“…Two investigators (CBB and HM) independently scored the quality of included studies. The risk of bias in individual studies was assessed using the Risk of Bias Tool for Prevalence Studies as previously described [16,18]. Discrepancies were resolved by consensus.…”

“…The methods of this systematic reviews and meta-analysis were described in a protocol [16] that was also registered with PROSPERO (CRD42018099434) Observational and intervention studies with data on iodine nutrition status in pregnancy conducted in the various African countries were included in this systematic review. The iodine nutrition status was de ned according to the WHO/ICCIDD classi cation of iodine intake of populations using median urinary iodine concentration [13].…”

“…Countries with o cial names in a language other than English were entered in the o cial form, and for countries that have changed names over time, both names were included in the search. The search strategy can be found in the published protocol for this review [16]. We also searched reference lists of relevant citations for articles of interest.…”

Prevalencia de bocio y yodo-deficiencia en embarazadas indígenas de cinco áreas no metropolitanas de Colombia 2019

“…La deficiencia de yodo es un problema de salud pública a nivel mundial que afecta tanto a los países desarrollados como a los que están en vías de desarrollo (4,(5)(6)(7)(8). Se calcula que entre el 20 % y el 60 % de los habitantes de los países en vías de desarrollo están en riesgo de sufrir transtornos por la deficiencia de yodo (4-7).…”

“…Posteriormente se determinó que, para el inicio de la gestación, las necesidades promedio de yodo (NPY) son de 150 µg/d y que al final de la gestación estas pueden llegar hasta 300 µg/d, cantidad necesaria para garantizar una concentración urinaria media de yodo óptima en el transcurso del embarazo (100-199 µg/L) (1,7). Las mujeres embarazadas con deficiencia leve de yodo (50-99 µg/L) y moderada (20-49 µg/L) pueden desarrollar hipotiroidismo subclínico, hipotiroidismo manifiesto o deficiencia aislada de T4, lo que se asocia con complicaciones materno-infantiles (7). Durante en el embarazo la deficiencia de yodo incrementa el riego de aborto, anomalías congénitas, restricción en el crecimiento intrauterino, y mortalidad perinatal (11) l. En el niño la deficiencia crónica de yodo causa hipotiroidismo congénito, cretinismo y deficiencias neuromotoras, intelectuales, conductuales y cognitivas, lo que lleva a problemas de aprendizaje, retraso mental irreversible, alteraciones en el crecimiento y defectos psicomotores (3,(9)(10)(11)(12)(13).…”