RATIONALE:Iodine is a micronutrient crucial in the early stages of human development, as it is essential for synthesising thyroid hormones involved in somatic growth and neurodevelopment. It is far better to prevent iodine deficiency than to treat it, since children are particularly vulnerable to iodine deficiency disorders, which involve a broad spectrum of consequences including endemic goitre, delayed growth and development of the central nervous system, intellectual impairment, and infant mortality. The primary dietary sources of iodine are iodised salt, seafood (animals and plants concentrate iodine from seawater), and grains from iodine-rich soils. Reliable evidence is needed on the benefits and harms of direct iodine supplementation in children and adolescents before considering its use to prevent the health consequences of iodine deficiency. OBJECTIVES:To assess the benefits and harms of iodine supplementation for preventing iodine deficiency in children and adolescents. SEARCH METHODS:We searched CENTRAL, MEDLINE, eight other databases, and two trials registries to 8 May 2025. We also searched the reference lists of retrieved studies. ELIGIBILITY CRITERIA:We included randomised controlled trials (RCTs) evaluating the benefits and harms of iodine supplementation alone (orally or by injection) or in combination with vitamins and minerals (orally or by injection) compared with placebo. OUTCOMES:Our critical outcomes were cognitive function assessed by validated scales, growth, hypothyroidism, and adverse events. Important outcomes included health-related quality of life, all-cause mortality, and goitre. RISK OF BIAS:We used the Cochrane RoB 2 tool to assess the risk of bias in the included studies. SYNTHESIS METHODS:Two review authors independently selected trials, extracted data, and assessed risk of bias. We used random-effects meta-analysis to combine data. We assessed the certainty of the evidence using GRADE. INCLUDED STUDIES:We included eight RCTs with a total of 2528 participants. The trials were conducted in seven countries between 1982 and 2009. The trials compared iodine supplementation (alone or with iron in one study) versus placebo. In one study, iodine supplementation was 150 μg daily for 28 weeks, while in the remaining studies, iodine supplementation was done in a single dose: 100 mg in a study on infants younger than 1 year, and a dose between 400 mg and 490 mg for children 6 to 17 years. Follow-up ranged from 3 to 22 months. SYNTHESIS OF RESULTS:Iodine supplementation versus placebo Iodine supplementation results in a slight increase in cognitive function compared to placebo (standardised mean difference 0.19, 95% confidence interval (CI) 0.04 to 0.34; 1 study, 166 participants; high-certainty evidence). Iodine supplementation may result in little to no difference in children's weight (kg) compared to placebo (mean difference (MD) -0.20, 95% CI -1.92 to 1.52; I² = 44%; 3 studies, 658 participants; low-certainty evidence). We downgraded the certainty of evidence by one level for imprecision and one level for heterogeneity. Iodine supplementation likely results in a large reduction in hypothyroidism compared to placebo (risk ratio (RR) 0.03, 95% CI 0.00 to 0.23; 1 study, 264 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for risk of bias. No study reported adverse events related to iodine or quality of life. Iodine supplementation likely reduces all-cause mortality in infants compared to placebo (RR 0.32, 95% CI 0.14 to 0.73; 1 study, 617 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for risk of bias. The evidence is very uncertain about the effect of iodine supplementation on the reduction of goitre (RR 0.68, 95% CI 0.15 to 3.07; I² = 97%; 2 studies, 432 participants; very low-certainty evidence). We downgraded the certainty of evidence by one level for imprecision, one level for heterogeneity, and one level for risk of bias. However, a sensitivity analysis removing the study with high risk of bias showed that iodine likely results in a large reduction in goitre (RR 0.31, 95% CI 0.22 to 0.45; 1 study, 230 participants; moderate-certainty evidence). Iodine plus iron supplementation versus placebo Iodine plus iron supplementation was compared to placebo in a single study. The evidence is very uncertain about the effect of iodine plus iron on weight (MD -0.40, 95% CI -1.44 to 0.64; 1 study, 146 participants; very low-certainty evidence). We downgraded the certainty of evidence by two levels for imprecision and one level for risk of bias. No other outcomes were assessed for this comparison. AUTHORS' CONCLUSIONS:Iodine supplementation, in the doses and follow-up periods evaluated in published RCTs, results in a slight increase in cognitive function and may result in little to no difference in growth. It likely reduces hypothyroidism and the risk of death in infants, but the evidence is very uncertain about its effect on the reduction of goitre. Future studies should focus on areas or populations in which iodine deficiency could be a problem, and include children of lower socioeconomic levels. They should evaluate higher doses of iodine administered during longer periods of treatment and follow-up times. FUNDING:This Cochrane review had no dedicated funding. REGISTRATION:Protocol (2023). DOI: 10.1002/14651858.CD014475.
OBJECTIVE:To systematically summarise people's health-related values and preferences related to fat intake. DESIGN:We searched five databases for studies reporting people's perspectives on fats. Screening, data extraction and risk of bias assessment were performed by two independent reviewers. Data was analysed using a convergent integrated approach and the certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation methodology. SETTING:Qualitative and quantitative studies from any country or language. PARTICIPANTS:Primary studies of adults, with or without cardiometabolic conditions. RESULTS:From 52 166 records, we included eleven quantitative and two qualitative studies; studies were primarily conducted in high-income countries. Five main themes were identified: (i) negative perception of fat in food, (ii) positive perception of vegetable oil as being beneficial to health, (iii) willingness to lower fat consumption, (iv) willingness to pay for healthier fat content and (v) barriers towards unsaturated fat consumption. The most frequently reported themes were negative perception of fat and willingness to consume low-fat products, while prioritising vegetable oil as a healthy fat. The evidence certainty for these themes was very low to moderate, rated down for risk of bias and indirectness issues. CONCLUSIONS:People's perception of fats and oils in diets is complex and often contradictory; most viewed high-fat products as unhealthy and associated with weight gain, while vegetable oils were generally perceived as beneficial. However, views varied significantly depending on sex, age and dietary patterns. Overall, the evidence supporting these perceptions is of moderate to very low certainty and to inform guideline recommendations more research is needed.
BACKGROUNDThe rate of successful pregnancies brought to term has barely increased since the first assisted reproductive technology (ART) technique became available. Vasodilators have been proposed to increase endometrial receptivity, thicken the endometrium, and favour uterine relaxation, all of which could improve uterine receptivity and enhance the chances for successful assisted pregnancy.OBJECTIVESTo evaluate the effectiveness and safety of vasodilators in women undergoing fertility treatment.SEARCH METHODSWe searched the following electronic databases, trial registers, and websites: the Cochrane Gynaecology and Fertility Group (CGF) Specialised Register of controlled trials, the Cochrane Central Register of of Controlled Trials, via the Cochrane Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, the Open System for Information on Grey Literature in Europe (OpenSIGLE), the Latin American and Caribbean Health Science Information Database (LILACS), clinical trial registries, and the reference lists of relevant articles. We conducted the search in October 2017 and applied no language restrictions.SELECTION CRITERIARandomised controlled trials (RCTs) comparing vasodilators alone or in combination with other treatments versus placebo or no treatment or versus other agents in women undergoing fertility treatment.DATA COLLECTION AND ANALYSISFour review authors independently selected studies, assessed risk of bias, extracted data, and calculated risk ratios (RRs). We combined study data using a fixed-effect model and assessed evidence quality using Grades of Recommendation, Assessment, Development and Evaluation Working Group (GRADE) methods. Our primary outcomes were live birth or ongoing pregnancy and vasodilator side effects. Secondary outcomes included clinical pregnancy, endometrial thickness, multiple pregnancy, miscarriage, and ectopic pregnancy.MAIN RESULTSWe included 15 studies with a total of 1326 women. All included studies compared a vasodilator versus placebo or no treatment. We judged most of these studies as having unclear risk of bias. Overall, the quality of evidence was low to moderate for most outcomes. The main limitations were imprecision due to low numbers of events and participants and risk of bias due to unclear methods of randomisation.Vasodilators probably make little or no difference in rates of live birth compared with placebo or no treatment (RR 1.18, 95% confidence interval (CI) 0.83 to 1.69; three RCTs; N = 350; I² = 0%; moderate-quality evidence) but probably increase overall rates of side effects including headache and tachycardia (RR 2.35, 95% CI 1.51 to 3.66; four RCTs; N = 418; I² = 0%; moderate-quality evidence). Evidence suggests that if 236 per 1000 women achieve live birth with placebo or no treatment, then between 196 and 398 per 1000 will do so with the use of vasodilators.Compared with placebo or no treatment, vasodilators may slightly improve clinical pregnancy rates (RR 1.45, 95% CI 1.19 to 1.77; 11 RCTs; N = 1054; I² = 6%; low-quality evidence). Vasodilators probably make little or no difference in rates of multiple gestation (RR 1.15, 95% CI 0.55 to 2.42; three RCTs; N = 370; I² = 0%; low-quality evidence), miscarriage (RR 0.83, 95% CI 0.37 to 1.86; three RCTs; N = 350; I² = 0%; low-quality evidence), or ectopic pregnancy (RR 1.48, 95% CI 0.25 to 8.69; two RCTs; N = 250; I² = 5%; low-quality evidence). All studies found benefit for endometrial thickening, but reported effects varied (I² = 92%) and ranged from a mean difference of 0.80 higher (95% CI 0.18 to 1.42) to 3.57 higher (95% CI 3.01 to 4.13) with very low-quality evidence, so we are uncertain how to interpret these results.AUTHORS' CONCLUSIONSEvidence was insufficient to show whether vasodilators increase the live birth rate in women undergoing fertility treatment. However, low-quality evidence suggests that vasodilators may slightly increase clinical pregnancy rates. Moderate-quality evidence shows that vasodilators increase overall side effects in comparison with placebo or no treatment. Adequately powered studies are needed so that each treatment can be evaluated more accurately.
Background Desert dust and sandstorms raise concerns about their adverse effects on human health. Over the last decade, special attention has been given to mineral dust particles from desert sand. However, evidence from previous literature reviews has yielded inconclusive results regarding their health effects. We aim to systematically synthesize evidence on the short-term health effects of desert dust exposure from major dust source areas. Methods The bibliographic search was conducted using the MEDLINE (PubMed), Scopus, and Web of Science databases to investigate the health effects of short-term exposure to desert dust in human populations, using time series or case-crossover study designs. Study selection and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We evaluated the risk of bias (RoB) for individual studies and the certainty of evidence (CoE) for environmental exposures, as developed by a group of experts convened by the World Health Organization (WHO). Publication bias was examined using funnel plots and Begg’s asymmetry test. Results A total of 71 studies were included in the review, covering data from 1993 to 2024. Most studies focused on Asian and African desert dust, with fewer studies from Arabian, American, and Australian regions. We found a significant increase in the risk for all-cause mortality (Relative Risk, RR = 1.0121, 95 %CI = [1.0045, 1.0199]). In addition, the mortality risk associated with particulate matter less than 10 μm (PM10) was slightly higher on dust days compared to non-dust days, while for particulate matter less than 2.5 μm (PM2.5), the risk was higher on non-dust days. We also observed a significant increase in the risk for cardiovascular mortality (RR = 1.0252, 95 % CI = [1.0100, 1.0407]) during dust days compared to non-dust days, but not for respiratory mortality (RR = 1.0001, 95 % CI = [0.9773, 1.0277]). The risk also increased for cardiovascular (RR = 1.0094, 95 % CI = [1.0014, 1.0174]) and respiratory morbidity (RR = 1.0693, 95 % CI = [1.0188, 1.1224]). Conclusion Exposure to desert dust and sandstorms is linked to increased risks of all-cause and cardiovascular mortality, as well as respiratory morbidity. The overall evidence quality for each exposure-outcome combination was assessed as moderate, although data limitations prevent the establishment of specific air quality thresholds for desert dust particles. This review highlights the need for targeted public health interventions in affected regions.
Background:Practice guidelines may reduce health inequities by addressing preventable and unjust differences in health. However, health equity considerations are often inadequately integrated into the guideline planning and development process. This article describes a pragmatic approach to enhancing health equity considerations within guidelines by introducing an extension to the GIN-McMaster Guideline Development Checklist (GDC). Methods:We reviewed the latest guidance on enhancing health equity considerations in guideline development to draft the checklist and deployed a global online survey from March 27th, 2024, to May 13th, 2024 to gather consensus. We conducted a methodological review of guideline development handbooks to identify best practices in health equity considerations. An advisory board comprised of diverse interest-holders informed the development of the checklist. We made revisions based on the survey feedback and review findings. Findings:We present 21 extension items spanning 16 of the 18 guideline development topics from the GIN-McMaster GDC. Key additions include planning for engagement with individuals experiencing inequities in guideline development activities, applying an equity lens, and considering health equity in recommendation formulation, dissemination and implementation strategies. This checklist gives value to lived experiences to enrich health equity assessments, complementing empirical evidence to inform guideline recommendations. Guideline developers should assess guideline sensitivity to health equity to determine resource prioritization for optimal implementation of the extension items. Interpretation:The GIN-McMaster health equity extension provides guidance for the streamlined integration of health equity considerations throughout the guideline development process. Using this tool alongside the original GIN-McMaster GDC may lead to more equitable and impactful guidelines. Funding:This project was partially funded by Public Health Agency of Canada. The funder was not involved in the conceptualization or design or the conduct of the project.
