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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.

SUBMITTER: Businge CB

PROVIDER: S-EPMC6706900 | biostudies-other | 2019 Aug

REPOSITORIES: biostudies-other

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

Businge Charles Bitamazire CB Longo-Mbenza Benjamin B Kengne Andre Pascal AP

Systematic reviews 20190822 1

<h4>Background</h4>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 i ...[more]

PMID: 31439032

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Project description:IntroductionPre-eclampsia is one of the leading causes of maternal and perinatal morbidity and mortality worldwide. Although subclinical hypothyroidism (SCH) in pregnancy is one of the established risk factors for pre-eclampsia, the link between iodine deficiency, the main cause of hypothyroidism and pre-eclampsia remains uncertain. About two billion people live in areas with iodine insufficiency. The increased renal blood flow during pregnancy leading to increased renal iodine clearance together with the increased placental transfer of iodine to the fetus leads to further iodine deficiency in pregnancy. Iodine is one of the most potent exogenous antioxidants whose deficiency is associated with oxidant imbalance and endothelial dysfunction, one of the mechanisms associated with increased risk of pre-eclampsia.Methods and analysisA systematic search of published literature will be conducted for case-control studies that directly determined the iodine nutrition status of women with pre-eclampsia and appropriate normotensive controls. A similar search will be conducted for cohort studies in which the incidence of pre-eclampsia among pregnant women with adequate and inadequate iodine nutrition status was reported. Databases including MEDLINE, EMBASE, Google Scholar, SCOPUS and Africa Wide Information will be searched up to 31 December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias of the included studies will be assessed using a Newcastle-Ottawa Scale. Appropriate meta-analytic techniques will be used to pool prevalence and incidence rates, odds and relative risk of pre-eclampsia from studies with similar features, overall and by geographical regions. Heterogeneity of the estimates across studies will be assessed and 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.Ethics and disseminationSince the proposed study will use published data, there is no requirement for ethical approval. This review seeks to identify the risk of pre-eclampsia associated with insufficient iodine nutrition in pregnancy. This will help to ascertain whether insufficient iodine intake may be an independent risk factor for pre-eclampsia. This will advise policy makers on the possibility of maximising iodine nutrition in pregnancy and reproductive age as one of the remedies for prevention of pre-eclampsia among populations at risk of inadequate iodine intake. This review is part of the thesis that will be submitted for the award of a PhD in Medicine to the Faculty of Health Sciences of the University of Cape Town. In addition the results will be published in a peer-reviewed journal.Prospero registration numberCRD42018099427.

Project description:BackgroundUS iodine intake, estimated from the median urinary iodine concentration of population representative data, has declined by half since the 1970s, which is problematic because maternal iodine intake is critical for fetal neurodevelopment. Relying on median urinary concentrations to assess iodine intake of populations is standard practice but does not describe the number of individuals with insufficient intake. Prevalence estimates of inadequate and excessive intake are better for informing public health applications but require multiple urine samples per person; such estimates have been generated in pediatric populations but not yet among pregnant women.ObjectiveOur aims were as follows: (1) to assess median urinary iodine concentrations across pregnancy for comparison with national data and (2) to estimate the prevalence of inadequate and excessive iodine intake among pregnant women in mid-Michigan.Study designData were collected from 2008 to 2015 as part of a prospective pregnancy cohort in which women were enrolled at their first prenatal clinic visit. Few exclusion criteria (<18 years or non-English speaking) resulted in a sample of women generally representative of the local community, unselected for any specific health conditions. Urine specimens were obtained as close as practicable to at least 1 specimen per trimester during routine prenatal care throughout pregnancy (n=1-6 specimens per woman) and stored at -80°C until urinary iodine was measured to estimate the iodine intake (n=1014 specimens from 464 women). We assessed urinary iodine across pregnancy by each gestational week of pregnancy and by trimester. We used multiple urine specimens per woman, accounted for within-person variability, performed data transformation to approximate normality, and estimated the prevalence of inadequate and excessive iodine intake using a method commonly employed for assessment of nutrient status.ResultsMaternal characteristics reflected the local population in racial and ethnic diversity and socioeconomic status as follows: 53% non-Hispanic white, 22% non-Hispanic black, and 16% Hispanic; 48% had less than or equal to high school education and 71% had an annual income of <$25,000. Median urinary iodine concentrations in the first, second, and third trimester-including some women contributing more than 1 specimen per trimester-were 171 μg/L (n=305 specimens), 181 μg/L (n=366 specimens), and 179 μg/L (n=343 specimens), respectively, with no significant difference by trimester (P=.50, Kruskal-Wallis test for equality of medians). The estimated prevalence of inadequate and excessive iodine intake was 23% and <1%, respectively.ConclusionMedian urinary iodine concentrations in each trimester were above the World Health Organization cutoff of 150 μg/L, indicating iodine sufficiency at the group level across pregnancy. However, the estimated prevalence of inadequate iodine intake was substantial at 23%, whereas prevalence of excessive intake was <1%, indicating a need for at least some women to increase consumption of iodine during pregnancy. The American Thyroid Association, the Endocrine Society, and the American Academy of Pediatrics recommend that all pregnant and lactating women receive a daily multivitamin or mineral supplement that contains 150 μg of iodine. The data presented here should encourage the collection of similar data from additional US population samples for the purpose of informing the American College of Obstetricians and Gynecologists' own potential recommendations for prenatal iodine supplementation.

Project description:IntroductionMultimorbidity has increased globally over the past two decades, due to ageing populations and increased burden of non-communicable diseases (NCDs). In a country like South Africa, with a growing burden of NCDs and a high prevalence of HIV, information on multimorbidity can improve planning for healthcare delivery and utilisation, and reduce costs in the context of constrained health resources. This review aims to synthesise prevalence studies on multimorbidity, and identify dominant clusters and trends of multimorbidity in South Africa.Methods and analysisWe will search electronic bibliographic databases (PubMed, Scopus, JSTOR, POPLINE, PsycINFO, ScienceDirect, Web of Science and CINAHL), and the reference lists of included articles. Two researchers will independently screen title and abstracts, and then full text to identify studies published before and in 2020 that report on prevalence of multimorbidity in South Africa. Risk of bias assessments will be done for each study. Information on the prevalence of multimorbidity and disease clusters will be extracted from each study. Where possible, prevalence of specific clusters of multimorbidity will be pooled using a random effects meta-analysis to account for variability between studies. The I2 statistic will be used to establish the extent of heterogeneity due to variation in prevalence estimates rather than due to chance. The systematic review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses.Ethics and disseminationOnly published journal articles will be included in the systematic review. This review received ethics approval as part of a larger project by the University of the Western Cape Biomedical Science Research Ethics Committee (BM20/5/8). The findings from this research will be used to estimate the prevalence of multimorbidity in South Africa and will contribute to the design of future research projects. The findings will be disseminated in a peer-reviewed journal article.Prospero registration numberCRD42020196895.

Project description:IntroductionThere are no data summarising the epidemiology of pulmonary hypertension (PH) among adults residing in Africa. Establishment of accurate epidemiological data on PH in this region may guide decision-making toward interventions to curb the burden of PH in Africa. The aim of this systematic review is to determine the prevalence, incidence and aetiologies of PH among people residing in Africa.Methods and analysisThis systematic review and meta-analysis will follow the MOOSE guidelines for reporting. Relevant abstracts published until 30 September 2016 will be searched in PubMed/Medline, EMBASE (Excerpta Medica Database), African Journals Online and Africa Index Medicus. Full texts of eligible studies will then be accessed through PubMed, Google Scholar, HINARI and the respective journals' websites. Relevant unpublished papers and conference proceedings will also be checked. Data will be analysed using STATA version 13 software. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate of the prevalence/incidence and aetiologies of PH across studies. Heterogeneity of studies will be evaluated by the ?2 test on Cochrane's Q statistic. Funnel plot analysis and Egger's test will be done to detect publication bias. Results will be presented by geographical region (central, eastern, northern, southern and western Africa).Ethics and disseminationThe current study is based on published data; ethical approval is, therefore, not required. This review will guide policy, practice and research by providing information on the magnitude of PH among people residing in Africa. Findings will be presented in evidence tables of individual studies as well as in summary tables. The final report of this systematic review, in the form of a scientific paper, will be published in a peer-reviewed journal. Furthermore, findings will be presented at conferences and submitted to relevant health authorities.Review registration numberPROSPERO CRD42016049351.

Project description:ObjectiveIn this systematic review, we estimate the prevalence of six types of arthritis in Africa; namely rheumatoid arthritis, osteoarthritis, juvenile arthritis, psoriatic arthritis, gout, and ankylosing spondylitis.MethodsWe comprehensively searched literature on 31 August 2014 in MEDLINE, EMBASE, Web of Science and the Cochrane Library to identify eligible studies from 1975 up to 31 July 2014. Two review authors independently selected studies, extracted data, and appraised studies. We carried out random effects meta-analysis of prevalence of arthritis and assessed heterogeneity through subgroup analyses. We performed separate analyses for population- and hospital-based studies, as well as rural and urban settings.Main findingsWe included 27 cross-sectional studies (20 population-based and 7 hospital-based) from Africa reporting on the prevalence of arthritis. The majority of the studies were from South Africa (44.4%, 12/27). Rheumatoid arthritis in urban settings ranged from 0.1% in Algeria, 0.6% in the DRC, to a meta-analysis overall prevalence of 2.5% in South Africa, and in rural settings ranged from a meta-analysis overall prevalence of 0.07% in South Africa, 0.3% in Egypt, to 0.4% in Lesotho. Osteoarthritis was the most prevalent form of arthritis and in urban settings it was 55.1% in South Africa and in rural settings, all in South Africa, ranged from 29.5%, 29.7%, up to 82.7% among adults aged over 65 years. Other results include highest prevalence of 33.1% for knee osteoarthritis in rural South Africa, 0.1% for ankylosing spondylitis in rural South Africa, 4.4% for psoriatic arthritis in urban South Africa, 0.7% for gout in urban South Africa, and 0.3% for juvenile idiopathic arthritis in urban Egypt. A third of the included studies had a low risk of bias (33.3%, 9/27), 40.8% (11/27) moderate risk, and 25.9% (7/27) had a high risk of bias.ConclusionsIn this systematic review, we have identified the paucity of latest prevalence data on arthritis in Africa. More studies are needed to address the prevalence and the true burden of this disease in Africa.

Project description:BACKGROUND:Evidence shows that adequate calcium intake during pregnancy reduces the risk of hypertensive disorders of pregnancy. In most low- and middle-income countries (LMICs) the daily calcium intake is well below recommendations. Mapping calcium intake during pregnancy worldwide and identifying populations with low calcium intake will provide the evidence base for more targeted actions to improve calcium intake. OBJECTIVE:To assess dietary calcium intake during pregnancy worldwide. SEARCH STRATEGY:MEDLINE and EMBASE (from July 2004 to November 2017). SELECTION CRITERIA:Cross-sectional, cohort, and intervention studies reporting calcium intake during pregnancy. DATA COLLECTION AND ANALYSIS:Five reviewers working in pairs independently performed screening, extraction, and quality assessment. We reported summary measures of calcium intake and calculated the weighted arithmetic mean for high-income countries (HICs) and LMICs independently, and for geographic regions, among studies reporting country of recruitment, mean intake, and total number of participants. When available, inadequate intakes were reported. MAIN RESULTS:From 1880 citations 105 works met the inclusion criteria, providing data for 73 958 women in 37 countries. The mean calcium intake was 948.3 mg/day (95% CI 872.1-1024.4 mg/day) for HICs and 647.6 mg/day (95% CI 568.7-726.5 mg/day) for LMICs. Calcium intakes below 800 mg/day were reported in five (29%) countries from HICs and in 14 (82%) countries from LMICs. CONCLUSION:These results are consistent with a lack of improvement in calcium dietary intake during pregnancy and confirm the gap between HICs and LMICs, with alarmingly low intakes recorded for pregnant women in LMICs. From the public health perspective, in the absence of specific local data, calcium supplementation of pregnant women in these countries should be universal. TWEETABLE ABSTRACT:Despite dietary recommendations, women in LMICs face pregnancy with diets low in calcium.

Project description:Despite the recent increasing worldwide attention towards pulmonary hypertension (PH), its epidemiology remains poorly described in Africa. Accordingly, we performed a systematic review and meta-analysis of PH prevalence, incidence and etiologies in Africa.We searched PubMed, EMBASE, African Journals Online, and Africa Index Medicus. Published observational studies until September 20, 2017, including adult participants residing in Africa were considered. Two review authors independently selected studies, assessed included studies for methodological quality, and extracted data. A random-effects model was used for meta-analysis. Heterogeneity was evaluated by the ? 2 test on Cochrane's Q statistic which is quantified by I2 values. Using Newcastle-Ottawa Scale, we considered a score of 0-4, 5-7, and 8-10 as indicative of high, moderate, and low risk of bias in included studies, respectively.Of 1611 entries, 25 studies were retained. Twelve (48%), seven (28%), and six (24%) papers had respectively a low, moderate and high risk of bias. The prevalence of PH widely varied across different populations: 9.8% (95% confidence interval: 3.2-19.3; I2?=?99.4%; 6 studies) in 11,163 people presenting with cardiac complaints; 10.6% (4.3-19.1; I2?=?90.3%; 4 studies) in 937 HIV-infected people; 32.9% (17.6-50.4; I2?=?97.2%; 3 studies) in 2077 patients with heart failure; 23.2% (15.2-32.2; I2?=?59.4%; 3 studies) in 248 patients on hemodialysis; 12.9% (11.8-14.0; I2?=?79.7%; 2 studies) in 3750 patients with rheumatic heart disease; 36.9% (29.7-44.3; I2?=?79.7; 2 studies) in 79 patients with sickle cell disease; 62.7% (49.0-74.7; 1 study) in 51 patients with chronic obstructive pulmonary disease; 25.4% (16.3-37.3; 1 study) in 63 patients with systemic lupus erythematous; 68.7% (62.8-74.1; 1 study) in 259 patients with cardiac surgery; and 7.4% (4.6-11.9; 1 study) in 202 patients with systemic sclerosis. No study reported PH incidence. From one international study (n?=?209), PH etiologies were: left heart disease (68.9%), pulmonary arterial hypertension (15.8%), lung disease and/or hypoxia (12.0%), chronic thromboembolic PH (1.9%) and unclear/multifactorial PH (15.8%).The prevalence of PH is relatively high in some populations in Africa, perhaps mainly driven by left heart diseases, highlighting the need for context-specific interventions.

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

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

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