Anonymous ID: bcda48 Jan. 26, 2020, 3:14 p.m. No.7924182   🗄️.is 🔗kun

Vitamin D helps fend off flu, asthma attacks: study

 

https://www.reuters.com/article/us-vitamind-study/vitamin-d-helps-fend-off-flu-asthma-attacks-study-idUSTRE62I3MK20100319

http://archive.is/opXOe

 

In a study of Japanese schoolchildren, vitamin D supplements taken during the winter and early spring helped prevent seasonal flu and asthma attacks.

The idea for the study, study chief Dr. Mitsuyoshi Urashima, told Reuters Health, came from an earlier study looking at whether vitamin D could help prevent the bone-thinning disease osteoporosis. The researchers in that study noticed that people taking vitamin D were three times less likely to report cold and flu symptoms.

This led Urashima, of Jikei University School of Medicine, Tokyo, and colleagues to randomly assign a group of 6- to 15-year-old children to take vitamin D3 supplements (1,200 international units daily) or inactive placebo during a cold and flu season.

Vitamin D3, or cholecalciferol, is more readily absorbed by the body and more potent than vitamin D2, or ergocalciferol, the form often found in multivitamins.

During the study, conducted between December 2008 and March 2009, 31 of 167 children taking placebo caught influenza A, the most common form of the virus, compared with only 18 of 167 taking vitamin D.

The vitamin D group was 58 percent less likely to catch influenza A, the researchers report in the American Journal of Clinical Nutrition.

Vitamin D also appeared to suppress asthma attacks in children with a history of asthma. Two children taking vitamin D had asthma attacks during the study, compared to 12 children taking placebo. Urashima admitted to being a bit surprised by this finding and hopes to confirm it in a randomized trial targeting children with asthma.

Anonymous ID: bcda48 Jan. 26, 2020, 3:24 p.m. No.7924309   🗄️.is 🔗kun

02/15/2017

Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data

 

https://www.bmj.com/content/356/bmj.i6583

http://archive.is/SuTRC

 

Objectives

To assess the overall effect of vitamin D supplementation on risk of acute respiratory tract infection, and to identify factors modifying this effect.

 

Design

Systematic review and meta-analysis of individual participant data (IPD) from randomised controlled trials.

 

Data sources

Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and the International Standard Randomised Controlled Trials Number registry from inception to December 2015.

 

Eligibility criteria for study selection

Randomised, double blind, placebo controlled trials of supplementation with vitamin D3 or vitamin D2 of any duration were eligible for inclusion if they had been approved by a research ethics committee and if data on incidence of acute respiratory tract infection were collected prospectively and prespecified as an efficacy outcome.

 

Results

25 eligible randomised controlled trials (total 11?321 participants, aged 0 to 95 years) were identified. IPD were obtained for 10?933 (96.6%) participants. Vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants (adjusted odds ratio 0.88, 95% confidence interval 0.81 to 0.96; P for heterogeneity <0.001). In subgroup analysis, protective effects were seen in those receiving daily or weekly vitamin D without additional bolus doses (adjusted odds ratio 0.81, 0.72 to 0.91) but not in those receiving one or more bolus doses (adjusted odds ratio 0.97, 0.86 to 1.10; P for interaction=0.05). Among those receiving daily or weekly vitamin D, protective effects were stronger in those with baseline 25-hydroxyvitamin D levels <25 nmol/L (adjusted odds ratio 0.30, 0.17 to 0.53) than in those with baseline 25-hydroxyvitamin D levels =25 nmol/L (adjusted odds ratio 0.75, 0.60 to 0.95; P for interaction=0.006). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (adjusted odds ratio 0.98, 0.80 to 1.20, P=0.83). The body of evidence contributing to these analyses was assessed as being of high quality.

 

Conclusions

Vitamin D supplementation was safe and it protected against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus doses experienced the most benefit.