Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials

ObjectivesTo assess the overall effect of vitamin D supplementation on risk of acute respiratory infection (ARI), and to identify factors modifying this effect. DesignWe conducted a systematic review and meta-analysis of data from randomised controlled trials (RCTs) of vitamin D for ARI prevention using a random effects model. Pre-specified sub-group analyses were done to determine whether effects of vitamin D on risk of ARI varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration or dosing regimen. Data SourcesMEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, ClinicalTrials.gov and the International Standard RCT Number (ISRCTN) registry from inception to May 2020. Eligibility Criteria for Selecting StudiesDouble-blind RCTs of supplementation with vitamin D or calcidiol, of any duration, were eligible if they were approved by a Research Ethics Committee and if ARI incidence was collected prospectively and pre-specified as an efficacy outcome. ResultsWe identified 40 eligible RCTs (total 30,956 participants, aged 0 to 95 years). Data were obtained for 29,841 (96.5%) of 30,909 participants in 39 studies. For the primary comparison of vitamin D supplementation vs. placebo, the intervention reduced risk of ARI overall (Odds Ratio [OR] 0.89, 95% CI 0.81 to 0.98; P for heterogeneity 0.009). No statistically significant effect of vitamin D was seen for any of the sub-groups defined by baseline 25(OH)D concentration. However, protective effects were seen for trials in which vitamin D was given using a daily dosing regimen (OR 0.75, 95% CI 0.61 to 0.93); at daily dose equivalents of 400-1000 IU (OR 0.70, 95% CI 0.55 to 0.89); and for a duration of [≤]12 months (OR 0.82, 95% CI 0.72 to 0.94). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (OR 0.94, 95% CI 0.81 to 1.08). Risk of bias within individual studies was assessed as being low for all but two trials. A funnel plot showed asymmetry, suggesting that small trials showing non-protective effects of vitamin D may have been omitted from the meta-analysis. ConclusionsVitamin D supplementation was safe and reduced risk of ARI, despite evidence of significant heterogeneity across trials. The overall effect size may have been over-estimated due to publication bias. Protection was associated with administration of daily doses of 400-1000 IU vitamin D for up to 12 months. The relevance of these findings to COVID-19 is not known and requires investigation. Systematic Review RegistrationCRD42020190633 O_TEXTBOXSummary Box What is already known on this subject?O_LIA previous individual participant data meta-analysis from 10,933 participants in 25 randomised controlled trials (RCTs) of vitamin D supplementation for the prevention of acute respiratory infection (ARI) demonstrated an overall protective effect (number needed to treat to prevent one ARI [NNT]=33).Sub-group analysis revealed most benefit in those with the lowest vitamin D status at baseline and not receiving bolus doses. C_LI What this study addsO_LIWe updated this meta-analysis with trial-level data from an additional 14 placebo-controlled RCTs published since December 2015 (i.e. new total of 39 studies with 29,841 participants). C_LIO_LIAn overall protective effect of vitamin D supplementation against ARI was seen (NNT=36). C_LIO_LIA funnel plot revealed evidence of publication bias, which could have led to an over-estimate of the protective effect. C_LIO_LINo statistically significant effect of vitamin D was seen for any of the sub-groups defined by baseline 25(OH)D concentration. C_LIO_LIStrongest protective effects were associated with administration of daily doses of 400-1000 IU vitamin D for [≤]12 months (NNT=8). C_LI C_TEXTBOX

Vitamin D status and risk of incident tuberculosis disease: A nested case-control study, systematic review, and individual-participant data meta-analysis.

BACKGROUND: Few studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk. METHODS AND FINDINGS: We assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies. CONCLUSION: Our findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk.

Bronze Age population dynamics and the rise of dairy pastoralism on the eastern Eurasian steppe.

Recent paleogenomic studies have shown that migrations of Western steppe herders (WSH) beginning in the Eneolithic (ca. 3300-2700 BCE) profoundly transformed the genes and cultures of Europe and central Asia. Compared with Europe, however, the eastern extent of this WSH expansion is not well defined. Here we present genomic and proteomic data from 22 directly dated Late Bronze Age burials putatively associated with early pastoralism in northern Mongolia (ca. 1380-975 BCE). Genome-wide analysis reveals that they are largely descended from a population represented by Early Bronze Age hunter-gatherers in the Baikal region, with only a limited contribution (∼7%) of WSH ancestry. At the same time, however, mass spectrometry analysis of dental calculus provides direct protein evidence of bovine, sheep, and goat milk consumption in seven of nine individuals. No individuals showed molecular evidence of lactase persistence, and only one individual exhibited evidence of >10% WSH ancestry, despite the presence of WSH populations in the nearby Altai-Sayan region for more than a millennium. Unlike the spread of Neolithic farming in Europe and the expansion of Bronze Age pastoralism on the Western steppe, our results indicate that ruminant dairy pastoralism was adopted on the Eastern steppe by local hunter-gatherers through a process of cultural transmission and minimal genetic exchange with outside groups.

Prevalence of pregnancy hypertensive disorders in Mongolia.

OBJECTIVE: To estimate the prevalence of preeclampsia in a contemporary population of Mongolian women living in urban and rural areas. We determined the sensitivity and specificity of diagnosis based on established diagnostic criteria and assessed whether local diagnostic criteria were similar to those used in the US. STUDY DESIGN: Cross-sectional study of urban and nomadic pregnant women recruited in Ulaanbaatar (n=136) and rural provinces (n=85). MAIN OUTCOME MEASURES: Preeclampsia defined as hypertension new to pregnancy after 20weeks and proteinuria (or protein creatinine ratio ⩾0.3 and dipstick reading>+1) or in the absence of proteinuria, hypertension and onset of: renal insufficiency, impaired liver function, thrombocytopenia, pulmonary edema, cerebral/visual symptoms. Prevalence of preeclampsia based on established criteria was compared with prevalence based on local physician's diagnosis. RESULTS: Prevalence of local physician diagnosed preeclampsia was 9.5% (13.2% urban, 3.5% rural). Prevalence based on established diagnostic criteria was 4.1% (4.4% urban, 3.5% rural). Sensitivity of physician's diagnosis was 23.8%, specificity was 98.0%, false negative rate was 2.0% and false positive rate was 76.2%. While prevalence based on local physician's diagnosis was over double that based on diagnostic criteria, overdiagnosis did not result in adverse effects. Women fulfilling diagnostic criteria for preeclampsia had babies with higher birth weights than women who did not (p-value=0.006). CONCLUSION: The 4.1% prevalence of preeclampsia in Mongolia was consistent with global estimates of 2-8%, suggesting the pathophysiology of preeclampsia here may be similar to that found globally. Sensitivity of physician's diagnosis was low, specificity was high.

Breast cancer incidence in Mongolia.

PURPOSE: Data on international variation in breast cancer incidence may help to identify additional risk factors. Substantially lower breast cancer rates in Asia than in North America and Western Europe are established, but differences within Asia have been largely ignored despite heterogeneity in lifestyles and environments. Mongolia's breast cancer experience is of interest because of its shared genetics but vastly different diet compared with other parts of Asia. METHODS: Age-standardized breast cancer incidence and mortality rates obtained from the International Association of Cancer Registries are presented for several Asian countries. Mongolian incidence rates obtained from its cancer registry describe incidence within the country. RESULTS: Breast cancer incidence in Mongolia (age standardized 8.0/100,000) is almost a third of rates in China (21.6/100,000), and over five times that of Japan (42.7/100,000) and Russia (43.2/100,000). Rates within Mongolia appear to have increased slightly over the last decade and are higher in urban than rural areas (annual percentage increase of age-standardized rates from 1998 to 2005 was 3.60 and 2.57 %, respectively). The increase in breast cancer incidence with age plateaus at menopause, as in other Asian populations. CONCLUSIONS: Mongolia's low breast cancer incidence is of particular interest because of their unusual diet (primarily red meat and dairy) compared with other Asian countries. More intensive study of potential dietary, reproductive and lifestyle factors in Mongolia with comparison to other Asian populations may provide more clarity in what drives the international breast cancer rate differences.

Testing potential effect of environmental endocrine disruptors in cow milk on reproductive index in female rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of endocrine disruptor chemicals in cow milk on female reproductive system.</p><p><b>METHODS</b>A two-generation reproduction was conducted according to U. S. FDA standard. Milk was fed in special bottle to Wistar rats of both sexes through two successive generations (F0 and F1) in the milk group while artificial milk was fed to rats in the control group. Twenty-four rats of each sex were mated in each group. Measurements were made according to this guideline.</p><p><b>RESULTS</b>Reproductive parameters in the milk group such as fertility index, gestation index, weights of uterus and ovary, days of vaginal opening, estrous cycles, histological morphological changes were comparable to those in the control group. However, the means of body weight had some differences. The body weight gains increased significantly in the milk-treated group in F1 and F2 generation compared with those in the control group. The concentration of insulin-like growth factor-1 (IGF-1) in blood in the milk group was comparable to that in the control group, but the standard deviation changed greatly in the milk-treated rats.</p><p><b>CONCLUSION</b>Endocrine disruptor chemicals in milk have no severe effects on the female reproductive system.</p>

The development of diabetes mellitus in Wistar rats kept on a high-fat/low-carbohydrate diet for long periods.

The present study was performed to determine the effect of long-term feeding with a high-fat/low-carbohydrate (HF/LC) diet on the onset of type-2 diabetes mellitus in normal rats. Male Wistar Imamichi rats were kept on a Control (carbohydrate 60%, fat 15%) or HF/ LC (carbohydrate 10%, fat 65%) diet for 16 mo. An intraperitoneal glucose tolerance test was performed once every 2 mo. Glucose tolerance was impaired 2 mo after the start of HF/LC diet feeding, accompanied by a decrease in the insulinogenic index. Along with time of HF/LC diet feeding, the glucose tolerance was further deteriorated with more serious impairment of insulin secretion and sensitivity. At the end of the experiment, 15 of 18 rats in the HF/LC group were diabetic, whereas only 4 of 17 rats in the Control group were diabetic. The present results demonstrate that longterm feeding with a HF/LC diet decreases the secretion and sensitivity of insulin, and induces diabetes mellitus in rats. Furthermore, long-term feeding with such a diet may produce adverse effects on the blood plasma lipid profile, with elevated levels of triglycerides, nonesterified fatty acids, total cholesterol, and reduced levels of high density protein cholesterol in the plasma.

The effects of estrogen-like products in milk on prostate and testes / 中华男科学杂志

<p><b>OBJECTIVES</b>To study the effects of estrogen-like products in milk on the male reproductive system.</p><p><b>METHODS</b>The incidence rates of testicular and prostatic cancers in 42 countries (regions), collected from the cancer incidence in five continent database (1988-1992), were correlated with the relative food consumption in these countries, which was provided by FAO database (1961-1990); two-generation reproduction test was taken by using Wistar rats according to FDA standard.</p><p><b>RESULTS</b>Among the food items examined, milk was most closely correlated (r = 0.711) with prostatic cancer incidence, followed by meat and coffee. As for testicular cancer, cheese was most closely correlated (r = 0.804) with the incidences in ages of 20-39, followed by animal fat and milk. No significant decreases of reproductive organ weight were found after the rats had been fed a lot of milk for long time.</p><p><b>CONCLUSIONS</b>The results suggest that further studies should be taken on the effects of estrogen-like products in milk on the male reproductive health.</p>