Serum 25-hydroxyvitamin D levels and the risk of depression: A systematic review and meta-analysis

Objective

No quantitative systematic review or meta-analysis of population-based epidemiological studies has been conducted to assess the association between serum 25-hydroxyvitamin D (25(OH)D) levels and the risk of depression. This study aimed to summarize the current evidence from cross-sectional and prospective cohort studies that have evaluated the association between 25(OH)D levels and the risk of depression.

Methods

Relevant studies were identified by systematically searching the PubMed, EMBASE, Web of Science, and PsycINFO databases through April 2012. Cross-sectional and cohort studies that reported adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association of interest were included. The reported risk estimates for 25(OH)D categories were recalculated, employing a comprehensive trend estimation from summarized dose-response data. A pooled OR was calculated separately for cross-sectional and cohort studies using random-effects models.

Results

In the meta-analysis, 25(OH)D levels were significantly inversely associated with depression in 5 of 11 case-control studies and 2 of 5 cohort studies. The pooled estimate of the adjusted OR of depression in 11 cross-sectional studies (n = 43,137) was 0.96 (95% CI = 0.94–0.99, I² = 63%) for a 10 ng/ml increase in 25(OH)D levels. The 5 included cohort studies comprised 12,648 participants, primarily elderly individuals, whose serum 25(OH)D levels were measured, and 2,663 experienced depression events during follow-up. The pooled adjusted OR of depression was 0.92 (95% CI = 0.87–0.98, I² = 50%) for a 10 ng/ml increase in 25(OH)D levels.

Conclusions

Our results indicate an inverse association between serum 25(OH)D levels and the risk of depression. Further studies are warranted to establish whether this association is causal.     

Relationship Between Serum Zinc Level and Metabolic Syndrome: A Meta-Analysis of Observational Studies

ABSTRACT

Objective: This research sought to summarize the evidence regarding the relationship between serum zinc level and metabolic syndrome (MetS).

Methods: The electronic databases of PubMed, Web of Science, and Embase were searched up to October 2017 for observational studies on the association between serum zinc level and MetS. The standard mean difference (SMD) and its corresponding 95% confidence interval (CI) of the serum zinc level for MetS versus control participants were calculated. In addition, the pooled odds ratio (OR) and relative risk (RR) of MetS for the highest versus lowest category of serum zinc level, as well as their corresponding 95% CI, were also calculated.

Results: A total of 11 observational studies (8 cross-sectional, 1 case-control, and 2 cohort studies) were included in this meta-analysis. The combined SMD demonstrated that the serum zinc level in MetS was higher than that in control participants (SMD = 0.11; 95% CI, 0.03–0.19; p = 0.009). Moreover, the overall multivariable-adjusted RR showed that the increased serum zinc level was associated with a higher risk of MetS (RR = 1.82; 95% CI, 1.33–2.50; p < 0.001). On the contrary, the overall multivariable-adjusted OR showed that there was no significant relationship between serum zinc level and MetS (OR = 1.00; 95% CI, 0.99–1.01; p = 0.841).

Conclusions: Although the serum zinc level in participants with MetS was significantly higher than that in control ones, the existing evidence was still insufficient to conclude a definite relationship between serum zinc level and MetS. More well-designed prospective cohort studies are needed to elaborate the concerned issues further.     

Skipping breakfast is associated with overweight and obesity: A systematic review and meta-analysis

ObjectiveIn recent years, many original studies have shown that skipping breakfast has been associated with overweight and obesity; however, the results of different studies are inconsistent. Therefore, we conducted a systematic review and meta-analysis of observational studies to synthesize the associations between skipping breakfast and the risk of overweight/ obesity.MethodsWe did a systematic search using Pubmed, and Ovid searched up to August 2019. Observational studies (cohort studies and cross-sectional studies) reporting adjusted Odds Ratio or Risk Ratio estimates for the association between breakfast skipping and overweight/obesity (including abdominal obesity). Summary odds ratio (or Risk Ratio) and 95% confidence intervals calculated with a random-effects model.Results45 observational studies (36 cross-sectional studies and 9 cohort studies) were included in this meta-analysis. In cross-sectional studies, The ORs of low frequency breakfast intake per week versus high frequency were 1.48 (95% CI 1.40–1.57; I² = 54.0%; P = 0.002) for overweight/obesity, 1.31 (95% CI 1.17–1.47; I² = 43.0%; P = 0.15) for abdominal obesity. In cohort studies, The RR of low-frequency breakfast intake per week versus high frequency was 1.44 (95% CI 1.25–1.66; I² = 61%; P = 0.009) for overweight/obesity.ConclusionsThis meta-analysis confirmed that skipping breakfast is associated with overweight/obesity, and skipping breakfast increases the risk of overweight/obesity. The results of cohort studies and cross-sectional studies are consistent. There is no significant difference in these results among different ages, gender, regions, and economic conditions.     

The Association between Vitamin D Status and Autism Spectrum Disorder (ASD): A Systematic Review and Meta-Analysis

The association between vitamin D status and autism spectrum disorder (ASD) is well-investigated but remains to be elucidated. We quantitatively combined relevant studies to estimate whether vitamin D status was related to ASD in this work. PubMed, EMBASE, Web of Science, and the Cochrane Library were searched to include eligible studies. A random-effects model was applied to pool overall estimates of vitamin D concentration or odds ratio (OR) for ASD. In total, 34 publications involving 20,580 participants were identified in this present study. Meta-analysis of 24 case–control studies demonstrated that children and adolescents with ASD had significantly lower vitamin D concentration than that of the control group (mean difference (MD): −7.46 ng/mL, 95% confidence interval (CI): −10.26; −4.66 ng/mL, p < 0.0001, I² = 98%). Quantitative integration of 10 case–control studies reporting OR revealed that lower vitamin D was associated with higher risk of ASD (OR: 5.23, 95% CI: 3.13; 8.73, p < 0.0001, I² = 78.2%). Analysis of 15 case–control studies barring data from previous meta-analysis reached a similar result with that of the meta-analysis of 24 case–control studies (MD: −6.2, 95% CI: −9.62; −2.78, p = 0.0004, I² = 96.8%), which confirmed the association. Furthermore, meta-analysis of maternal and neonatal vitamin D showed a trend of decreased early-life vitamin D concentration in the ASD group (MD: −3.15, 95% CI: −6.57; 0.26, p = 0.07, I² = 99%). Meta-analysis of prospective studies suggested that children with reduced maternal or neonatal vitamin D had 54% higher likelihood of developing ASD (OR: 1.54, 95% CI: 1.12; 2.10, p = 0.0071, I² = 81.2%). These analyses indicated that vitamin D status was related to the risk of ASD. The detection and appropriate intervention of vitamin D deficiency in ASD patients and pregnant and lactating women have clinical and public significance.     

Association of vitamin A and β-carotene with risk for age-related cataract: A meta-analysis

ObjectiveWhether vitamin A and β-carotene as nutrients are protective factors against cataracts remains unclear. Thus, the aim of this study was to summarize the evidence from epidemiologic studies of vitamin A and β-carotene with the risk for cataract.MethodsPertinent studies were identified by a search of PubMed, Web of Science, Google Scholar, and Wan Fang Med Online. A fixed- or random-effects model was used based on heterogeneity test. Meta-regression and “leave-one-out” analysis were used to explore potential sources of between-study heterogeneity. Publication bias was estimated using Egger's regression asymmetry test.ResultsTwenty-two articles were included in this meta-analysis. The relative risk (RR; 95% confidence interval [CI]) for cataract for the highest versus lowest category of serum β-carotene levels was 0.827 (95% CI, 0.736–0.930), and the association was significant between β-carotene intake and cataract risk (RR, 0.937; 95% CI, 0.880–0.997). Significant association of cataract risk with vitamin A intake was found overall (RR, 0.831; 95% CI, 0.757–0.913). However, no significant association was found between serum vitamin A and cataract risk (RR, 0.925; 95% CI, 0.675–1.266; I² = 63.1%), but an inverse association was observed with risk for cataract with serum vitamin A after sensitivity analysis (RR, 0.765; 95% CI, 0.654–0.894; I² = 29.1%).ConclusionsGreater vitamin A and β-carotene intakes might be inversely associated with risk for cataract.     

Consumption of red and processed meat and risk for esophageal squamous cell carcinoma based on a meta-analysis

PurposeTo provide a quantitative assessment of the association between red and processed meat intake and the risk of esophageal squamous cell carcinoma (ESCC), we summarized the evidence from observational studies.MethodsRelevant studies were identified in MEDLINE and EMBASE until October 31, 2012. Summary relative risks with 95% confidence intervals (CIs) were pooled with high versus low and linear dose-response random-effects models.ResultsA total of 21 studies (19 case-control and two cohort studies) with 6499 ESCC cases were included in this meta-analysis. Based on high versus low analysis, the summary relative risks of ESCC were 1.57 (95% CI, 1.26–1.95; P_{heterogeneity} = .003, I² = 56.0%) for red meat intake and 1.55 (95% CI, 1.22–1.97; P_{heterogeneity} = .029, I² = 45.3%) for processed meat intake. Subgrouped and sensitivity analyses revealed that the increment of ESCC risk with intakes of red meat and processed meat was stable and robust. These results are consistent with the results of the dose-response analyses. There was evidence of a nonlinear association of processed meat intake and ESCC risk (P_nonlinearity = .019).ConclusionsIntake of red and processed meat may be associated with significantly increased risk of ESCC. Further investigations with prospective designs are warranted.     

Dietary Magnesium Intake and Metabolic Syndrome in the Adult Population: Dose-Response Meta-Analysis and Meta-Regression

Increasing evidence has suggested an association between dietary magnesium intake and metabolic syndrome. However, previous research examining dietary magnesium intake and metabolic syndrome has produced mixed results. Our objective was to determine the relationship between dietary magnesium intake and metabolic syndrome in the adult population using a dose-response meta-analysis. We searched the PubMed, Embase and the Cochrane Library databases from August, 1965, to May, 2014. Observational studies reporting risk ratios with 95% confidence intervals (CIs) for metabolic syndrome in ≥3 categories of dietary magnesium intake levels were selected. The data extraction was performed independently by two authors, and the quality of the studies was evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). Based on eight cross-sectional studies and two prospective cohort studies, the pooled relative risks of metabolic syndrome per 150 mg/day increment in magnesium intake was 0.88 (95% CI, 0.84–0.93; I² = 36.3%). The meta-regression model showed a generally linear, inverse relationship between magnesium intake (mg/day) and metabolic syndrome. This dose-response meta-analysis indicates that dietary magnesium intake is significantly and inversely associated with the risk of metabolic syndrome. However, randomized clinical trials will be necessary to address the issue of causality and to determine whether magnesium supplementation is effective for the prevention of metabolic syndrome.     

Dose-response relation between serum total cholesterol levels and overall cancer risk: evidence from 12 prospective studies involving 1,926,275 participants

This study aimed to clarify the association between serum total cholesterol (TC) levels and overall cancer risk. Study-specific relative risks (RR) and 95% confidence intervals (CI) were pooled using a random-effects model, and dose–response relation was also evaluated. Twelve prospective studies were identified with a total of 1,926,275 participants and 13,1676 cases. High levels of serum TC showed an inverse association with overall cancer risk (RR for the highest versus the lowest category: 0.87, 95% CI: 0.83?～?0.90; I²?=?52.5%). A linear dose-response relation between serum TC levels and overall cancer risk was found (p?=?.004 for Wald test; I²?=?49.6%), and the pooled RR was 0.92 (95% CI: 0.89?～?0.94) for 3?mmol/L, 0.86 (95% CI: 0.81?～?0.90) for 5?mmol/L, 0.80 (95% CI: 0.74?～?0.87) for 7?mmol/L. Our dose-response meta-analysis of 12 prospective studies indicated that higher serum TC levels were significantly associated with reduced cancer risk.     

Vitamin D Deficiency Increases the Risk of Gestational Diabetes Mellitus: A Meta-Analysis of Observational Studies

The results investigating the relationship between vitamin D levels and gestational diabetes mellitus (GDM) are inconsistent. Thus, we focused on evaluating the association of vitamin D deficiency with GDM by conducting a meta-analysis of observed studies. A systematic literature search was conducted via PubMed, MEDLINE, and Cochrane library to identify eligible studies before August 2015. The meta-analysis of 20 studies including 9209 participants showed that women with vitamin D deficiency experienced a significantly increased risk for developing GDM (odds ratio (OR) = 1.53; 95% confidence intervals (CI), 1.33, 1.75) with a little heterogeneity (I² = 16.20%, p = 0.252). A noteworthy decrease of 4.93 nmol/L (95% CI, −6.73, −3.14) in serum 25(OH)D was demonstrated in the participants with GDM, and moderate heterogeneity was observed (I² = 61.40%, p = 0.001). Subgroup analysis with study design showed that there were obvious heterogeneities in nested case–control studies (I² > 52.5%, p < 0.07). Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect. In summary, the evidence from this meta-analysis indicates a consistent association between vitamin D deficiency and an increased risk of GDM. However, well-designed randomized controlled trials are needed to elicit the clear effect of vitamin D supplementation on prevention of GDM.     

The effects of vitamin D supplementation on endothelial activation among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials

Background and objective

The current systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of vitamin D supplementation on endothelial activation among patients with metabolic syndrome and related disorders.

Methods

Cochrane library, Embase, PubMed, and Web of Science database were searched to identify related RCTs published before 30th April 2018. The heterogeneity among the included studies was assessed using Cochran’s Q test and I-square (I²) statistic. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as summary effect size.

Results

Fourteen clinical trials that contained a total of 1253 participants were included in the current meta-analysis. Vitamin D supplementation significantly decreased von willebrand factor (vWF) (SMD -0.27; 95% CI, ??0.46, ??0.08; P?=?0.006; I²:40.5%). However, we found no significant impact of vitamin D supplementation on intercellular adhesion molecule 1(ICAM-1) (SMD -1.96; 95% CI, ??4.02, 0.09; P?=?0.06; I²:97.4%), vascular celladhesion molecule 1 (VCAM-1) (SMD -0.50; 95% CI, ??1.19, 0.19; P?=?0.15; I²:91.2%), on E-selectin (SMD -0.04; 95% CI, ??0.36, 0.28; P?=?0.81; I²:78.8%) and endothelin (SMD -0.49; 95% CI, ??1.18, 0.19; P?=?0.15; I²:90.5%). The pooled data from trials of vitamin D supplementation with dosage of ≤4000?IU/day (??0.37, 95% CI: -0.65, ??0.10, I²: 73.5%) significantly reduced vWF concentrations, while there was no effect of vitamin D supplementation on vWF concentrations among trials with the dosage of intervention >?4000?IU/day (??0.17, 95% CI: -0.43, 0.10, I²: 0.0%). VWF concentrations significantly reduced in pooled data from trials with duration study ≤8?weeks (??0.37, 95% CI: -0.67, ??0.07, I²: 60.6%), but there was no effect of vitamin D supplementation on vWF concentrations among trials with >?8?weeks (??0.20, 95% CI: -0.45, 0.05, I²: 0.0%). While there was no effect of vitamin D supplementation on vWF concentrations among trials with total sample size of ≤60 patients (??0.03, 95% CI: -0.42, 0.36, I²: 0.0%), vWF concentrations in trials with more than 60 patients decreased significantly (??0.34, 95% CI: -0.56, ??0.12, I²: 60.9%).

Conclusions

Overall, the current meta-analysis demonstrated that vitamin D supplementation to patients with metabolic syndrome and related disorders resulted in an improvement in vWF, but did not affect ICAM-1, VCAM-1, E-selectin and endothelin levels.

     

Coffee Drinking and the Risk of Endometrial Cancer: An Updated Meta-Analysis of Observational Studies

Background: Several compounds contained in coffee have been found to suppress carcinogenesis in experimental studies. We conducted a dose–response meta-analysis to assess the impact of coffee consumption on the risk of endometrial cancer. Materials and methods: We searched MEDLINE and EMBASE databases for studies published up to August 2016. Using random effects models, we estimated summary relative risks (RR) for cohort studies and odds ratios (OR) for case-control studies with 95% confidence intervals (CI). Dose–response analyses were conducted by using generalized least square trend estimation. Results: We identified 12 cohort studies and 8 case-control studies eligible for inclusion, contributing with 11,663 and 2,746 endometrial cancer cases, respectively. The summary RR for highest compared with lowest coffee intake was 0.74 (95% CI: 0.68–0.81; p_{heterogeneity} = 0.09, I² = 32%). The corresponding summary RR among cohort studies was 0.78 (95% CI: 0.71–0.85; p_{heterogeneity} = 0.14, I² = 31.9%) and 0.63 (95% CI: 0.53–0.76; p_{heterogeneity} = 0.57, I² = 0%) for case-control studies. One-cup increment per day was associated with 3% risk reduction (95% CI: 2–4%) in cohort studies and 12% (95% CI: 5–18%) in case-control studies. After pooling the results from 5 cohort studies, the association remained significant only in women with body mass index over 30 (RR = 0.71, 95% CI: 0.61–0.81). Conclusion: The results from our meta-analysis strengthen the evidence of a protective effect of coffee consumption on the risk of EC and further suggest that increased coffee intake might be particularly beneficial for women with obesity.     

Coffee Consumption and Prostate Cancer Risk: A Meta-Analysis of Cohort Studies

This meta-analysis was conducted to assess the association between coffee consumption and prostate cancer risk. Thirteen cohort studies with 34,105 cases and 539,577 participants were included in the meta-analysis. The summary relative risks (RRs) with 95% confidence intervals (CIs) for different coffee intake levels were calculated. Dose-response relationship was assessed using generalized least square trend estimation. The pooled RR for the highest vs. lowest coffee intake was 0.90 (95% CI: 0.85–0.95), with no significant heterogeneity across studies (P = 0.267; I²= 17.5%). The dose-response analysis showed a lower cancer risk decreased by 2.5% (RR = 0.975; 95% CI: 0.957–0.995) for every 2 cups/day increment in coffee consumption. Stratifying by geographic region, there was a statistically significant protective influence of coffee on prostate cancer risk among European populations. In subgroup analysis of prostate cancer grade, the summary RRs were 0.89 (95% CI: 0.83–0.96) for nonadvanced, 0.82 (95% CI: 0.61–1.10) for advanced and 0.76 (95% CI: 0.55–1.06) for fatal diseases. Our findings suggest that coffee consumption may be associated with a reduced risk of prostate cancer and it also has an inverse association with nonadvanced prostate cancer. Because of the limited number of studies, more prospective studies with large sample size are needed to confirm this association.     

Exposure to glyphosate and risk of non-hodgkin lymphoma: an updated meta-analysis

Objective:We updated a recent systematic review and meta-analysis of epidemiologic studies to help clarifying the association between exposure to glyphosate and risk of non-Hodgkin lymphoma (NHL).Methods:We conducted an updated search of the literature, and identified a total of 15 relevant publications, from which we extracted results from six non-overlapping studies. We performed random-effects meta-analyses for ever-exposure to glyphosate, dose-response, and risk of specific NHL subtypesResults:The meta-RR for ever-exposure to glyphosate was 1.05 (95% confidence interval [CI] 0.90-1.24; I² = 0%). The meta-RR for the highest category of exposure was 1.15 (95% CI 0.72-1.83; 3 studies). The meta-RR for diffuse large B-cell lymphoma (DLBCL) was 1.29 (95% CI 1.02-1.63; 4 studies), that for follicular lymphoma was 0.84 (95% CI 0.61-1.17), and that for chronic lymphocytic leukemia/small lymphocytic lymphoma was 1.33 (95% CI 0.65-2.70). There was indication of publication bias.Conclusions:This updated meta-analysis reinforces our previous conclusion of a lack of an association between exposure to glyphosate and risk of NHL overall, although an association with DLBCL cannot be ruled out.     

Cognitive Frailty as a Predictor of Future Falls in Older Adults: A Systematic Review and Meta-Analysis

ObjectivesTo examine the association between cognitive frailty and the risk of future falls among older adults.DesignSystematic review and meta-analysis.Setting and ParticipantsOlder people aged ≥60 years with cognitive frailty from community, hospital, or both.MethodsPubMed, EMBASE, Web of Science, the Cochrane Library, Wanfang Database, China Knowledge Resource Integrated Database (CNKI), Weipu Database (VIP), and Chinese Biomedical Database (CBM) were searched for relevant studies published from the inception of the database until June 14, 2022. Stata 16.0 software was used to perform the meta-analysis. A random effects model was used to pool the prevalence of falls in older adults over age 60 years with cognitive frailty and the strength of the association between cognitive frailty and falls [odds ratios (ORs) and 95% CIs]. Quality assessment, heterogeneity, and sensitivity analyses were also conducted. A study protocol was registered in PROSPERO (CRD42022331323).ResultsThe review included 18 studies in qualitative synthesis, 14 of which were in meta-analysis. Eleven sets of cross-sectional data involving 23,025 participants and 5 sets of longitudinal data involving 11,924 participants were used in the meta-analysis. The results showed that the overall prevalence of falls in 1742 people with cognitive frailty was 36.3% (95% CI 27.9-44.8, I² = 93.4%). Longitudinal study results showed that cognitively frail individuals had a higher risk of falls (OR 3.02, 95% CI 2.11-4.32, I² = 0.0%, P = .406), compared to robust participants without cognitive impairment; physically frail people (alone) had a moderate risk of falls (OR 2.16, 95% CI 1.42-3.30, I² = 9.7%, P = .351); cognitively impaired people (alone) had a lower risk of falls (OR 1.36, 95% CI 1.03-1.79, I² = 0.0%, P = .440). Among cross-sectional studies, cognitive frailty was associated with the risk of falls (OR 2.74, 95% CI 2.20-3.40, I² = 53.1%, P = .019). Although high heterogeneity was noted among 11 cross-sectional studies reporting ORs, the sensitivity analysis showed that no single study significantly affected the final pooled results.Conclusions and ImplicationsThis systematic review and meta-analysis confirms the findings that cognitive frailty was demonstrated to be a significant predictor of future falls in older adults. However, further prospective investigations are warranted.     

Association of Vitamin B Status with Risk of Dementia in Cohort Studies: A Systematic Review and Meta-Analysis

ObjectiveTo examine the association between B vitamins status and the risk of dementia in older adults through a systematic review and meta-analysis of cohort studies.DesignSystematic review and meta-analysis.Setting and participantsOlder adults aged ≥60 years from community, nursing home, institution, or hospital.MethodsPubMed, Cochrane Library, EMBASE, Web of Science, CINAHL, ClinicalTrials, WHO-ICTRP, NHS Trusts, and ACTR were searched from the date of their inception up to November 28, 2021. We included cohort studies that assessed the association between serum B vitamins or B vitamins intake and the risk of dementia among older adults aged ≥60 years. The quality of all studies was assessed by the modified Newcastle-Ottawa Scale (NOS). The hazard ratios (HRs) and 95% CIs were calculated by the random effects model. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to rate the certainty of evidence.ResultsEleven cohort studies with sample sizes ranging from 233 to 3634 were included in the meta-analysis. Levels of serum folate showed statistically significant association with the risk of dementia (≥10 nmol/L: HR 1.57, 95% CI 1.01-2.46, low certainty; <10 nmol/L: HR 0.93, 95% CI 0.88-0.99, very low certainty). However, levels of vitamin B₆ intake showed no statistically significant effects on risk of dementia; levels of serum vitamin B₁₂ and vitamin B₁₂ intake also showed no statistically significant effects on risk of dementia in older adults.Conclusions and ImplicationsThe results from our meta-analysis suggest that vitamin B₆, B₁₂, and folate may not be modifiable risk factors for dementia among older adults. Current evidence on the relationship between vitamin B status and dementia is not sufficient for development of vitamin B recommendations. More high-quality cohort studies are needed to confirm the relationship between the two in the future.     

Body fatness,diabetes, physical activity and risk of kidney stones: a systematic review and meta-analysis of cohort studies

We conducted a systematic review and meta-analysis to clarify the association between adiposity, diabetes, and physical activity and the risk of kidney stones. PubMed and Embase were searched up to April 22nd 2018 for relevant studies. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random effects models. Thirteen cohort studies were included. The summary relative risk was 1.21 (95% CI 1.12–1.30, I²?=?76%, n?=?8) per 5 unit increment in BMI, 1.16 (95% CI 1.12–1.19, I²?=?0%, n?=?5) per 10 cm increase in waist circumference, 1.06 (95% CI 1.04–1.08, I²?=?67%, n?=?3) per 5 kg increase in weight and 1.12 (95% CI 1.06–1.18, I²?=?86%, n?=?3) per 5 kg of weight gain. The summary RR was 1.16 (95% CI 1.03–1.31, I²?=?51%, n?=?10) for participants with diabetes compared to participants without diabetes, and 0.93 (95% CI 0.78–1.10, I²?=?80%, n?=?4) for high vs. low physical activity. These results suggest a positive association between adiposity and diabetes and the risk of kidney stones, but no association with physical activity.     

Salt and obesity: a systematic review and meta-analysis of observational studies

Background: Existing research has investigated the association between sodium intake and obesity. We aim to conduct a systematic review and meta-analysis of reported evidence regarding the association between sodium intake and obesity.

Methods: Multiple electronic databases (PubMed, Scopus, and Google Scholar) were searched for observational studies published until August 2016. A systematic literature review identified 11 cohort and 21 cross-sectional studies.

Result: Among the 32 studies identified in the systematic literature search, only 18 cross-sectional reports had sufficient data to be included in the meta-analysis. Higher sodium consumption was associated with greater BMI (weighed mean difference (WMD)?=?1.24?kg/m², 95%CI: 0.80, 1.67; I^2?=^?98.4%; p?p?<.0001) greater waist circumference (WC).

Conclusion: The present meta-analysis suggests that sodium consumption was associated with greater BMI and WC.     

Sugar- and Artificially Sweetened Beverages Consumption Linked to Type 2 Diabetes,Cardiovascular Diseases,and All-Cause Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Although studies have examined the association between habitual consumption of sugar- (SSBs) and artificially sweetened beverages (ASBs) and health outcomes, the results are inconclusive. Here, we conducted a dose-response meta-analysis of prospective cohort studies in order to summarize the relationship between SSBs and ASBs consumption and risk of type 2 diabetes (T2D), cardiovascular diseases (CVDs), and all-cause mortality. All relevant articles were systematically searched in PubMed, Embase, and Ovid databases until 20 June 2020. Thirty-four studies met the inclusion criteria and were eligible for analysis. Summary relative risks (RRs) and 95% confidence intervals (95% CI) were estimated using random effects or fixed-effects model for highest versus lowest intake categories, as well as for linear and non-linear relationships. With each additional SSB and ASB serving per day, the risk increased by 27% (RR: 1.27, 95%CI: 1.15–1.41, I² = 80.8%) and 13% (95%CI: 1.03–1.25, I² = 78.7%) for T2D, 9% (RR: 1.09, 95%CI: 1.07–1.12, I² = 42.7%) and 8% (RR: 1.08, 95%CI: 1.04–1.11, I² = 45.5%) for CVDs, and 10% (RR: 1.10, 95%CI: 0.97–1.26, I² = 86.3%) and 7% (RR: 1.07, 95%CI: 0.91–1.25, I² = 76.9%) for all-cause mortality. Linear relationships were found for SSBs with T2D and CVDs. Non-linear relationships were found for ASBs with T2D, CVDs, and all-cause mortality and for SSBs with all-cause mortality. The findings from the current meta-analysis indicate that increased consumption of SSBs and ASBs is associated with the risk of T2D, CVDs, and all-cause mortality.     

Association of Vitamin D Status with SARS-CoV-2 Infection or COVID-19 Severity: A Systematic Review and Meta-analysis

This systematic review was conducted to summarize and clarify the evidence on the association between 25-hydroxyvitamin-D [25(OH)D] concentrations and coronavirus disease 2019 (COVID-19) risk and outcomes. PubMed, Scopus, and Web of Science databases and Google Scholar were searched up to 26 November 2020. All retrospective and prospective cohort, cross-sectional, case-control, and randomized controlled trial studies that investigated the relation between 25(OH)D and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 severity were included. Thirty-nine studies were included in the current systematic review. In studies that were adjusted (OR: 1.77; 95% CI: 1.24, 2.53; I²: 44.2%) and nonadjusted for confounders (OR: 1.75; 95% CI: 1.44, 2.13; I²: 33.0%) there was a higher risk of SARS-CoV-2 infection in the vitamin D deficiency (VDD) group. Fifteen studies evaluated associations between VDD and composite severity. In the studies that were adjusted (OR: 2.57; 95% CI: 1.65, 4.01; I² = 0.0%) and nonadjusted for confounders (OR: 10.61; 95% CI: 2.07, 54.23; I² = 90.8%) there was a higher severity in the VDD group. Analysis of studies with crude OR (OR: 2.62; 95% CI: 1.13, 6.05; I²: 47.9%), and adjusted studies that used the Cox survival method (HR: 7.67; 95% CI: 3.92, 15.03; I²: 0.0%) indicated a significant association of VDD with mortality, while in adjusted studies that used logistic regression, no relation was observed (OR: 1.05; 95% CI: 0.63, 1.75; I²: 76.6%). The results of studies that examined relations between VDD and intensive care unit (ICU) admission, pulmonary complications, hospitalization, and inflammation were inconsistent. In conclusion, although studies were heterogeneous in methodological and statistical approach, most of them indicated a significant relation between 25(OH)D and SARS-CoV-2 infection, COVID-19 composite severity, and mortality. With regard to infection, caution should be taken in interpreting the results, due to inherent study limitations. For ICU admission, inflammation, hospitalization, and pulmonary involvement, the evidence is currently inconsistent and insufficient.     

Vitamin D Supplementation during Pregnancy: An Evidence Analysis Center Systematic Review and Meta-Analysis

BackgroundGiven the high rates of vitamin D deficiency among pregnant women and possible effects on offspring health, a systematic review on this topic was conducted to help inform future practice guidelines.ObjectiveTo evaluate associations between maternal vitamin D supplementation, maternal 25-hydroxyvitamin D (25(OH)D) concentrations, and health outcomes.MethodsA PubMed literature search was conducted to identify studies that examined the health effects of vitamin D supplementation during pregnancy on maternal and infant health outcomes published from 2000 to 2016. Among 976 identified publications, 20 randomized clinical trials met the inclusion criteria. The initial search was extended to include five studies published between July 2016 and September 2018.Main outcome measuresMaternal and infant 25(OH)D concentrations, gestational diabetes, preeclampsia or gestational hypertension, cesarean section, maternal parathyroid hormone and calcium concentrations, and infant gestational age, birth weight, and birth length.Statistical analysesMean differences, odds ratios, and 95% CIs were calculated, only for the initial search, using separate random-effects meta-analyses for each outcome.ResultsEvidence was good or strong that maternal vitamin D supplementation significantly increased maternal (13 studies, n=18, mean difference, 14.1 ng/mL [35.2 nmol/L]; 95% CI=9.6-18.6 ng/mL [24.0-46.4 nmol/L]) and infant (nine studies, n=12; 9.7, 5.2, 14.2 ng/mL [24.2, 12.9, 35.5 nmol/L]) 25(OH)D concentrations, although heterogeneity was significant (I²=95.9% and I²=97.4, respectively, P<0.001). Evidence was fair that vitamin D supplementation significantly decreases maternal homeostatic model assessment-insulin resistance (five studies, n=7; −1.1, −1.5, −0.7) and increases infant birth weight (nine studies, n=11, 114.2, 63.4, 165.1 g), both had insignificant heterogeneity. A null effect of maternal supplementation on other maternal (preeclampsia, cesarean section) and infant (gestational age, birth length) outcomes was found.ConclusionsResults show vitamin D supplementation during pregnancy improves maternal and infant 25(OH)D concentrations and may play a role in maternal insulin resistance and fetal growth. To further inform practice and policies on the amount of vitamin D, which supports a healthy pregnancy, high quality dose-response randomized clinical trials, which assess pregnancy-specific 25(OH)D thresholds, and appropriately powered clinical outcomes are needed.