Vitamin D supplementation was effective in reducing the risk for acute respiratory infections such as the common cold and influenza, according to a meta-analysis recently published in BMJ.
“Our study reports a major new indication for vitamin D supplementation: the prevention of acute respiratory tract infection. We also show that people who are very deficient in vitamin D and those receiving daily or weekly supplementation without additional bolus doses experienced particular benefit,” Adrian R. Martineau, MRCP, PhD, The London School of Medicine and Dentistry, Queen Mary University of London, and colleagues wrote.
The researchers searched MEDLINE and other databases, and identified 25 randomized, controlled trials containing 11,321 participants that studied supplementation with vitamin D, vitamin D2 or vitamin D3 and included data on the occurrence of acute respiratory tract infection prospectively and prespecified as an efficacy outcome. Dosing regimens were daily or weekly without bolus dosing vs. a regimen including at least one bolus dose of at least 30,000 IU vitamin D), dose size (daily equivalent < 800 IU, 800-1,999 IU and/or ≥2,000 IU).
They found that vitamin D supplementation reduced the risk for acute respiratory tract infection among all participants (AOR = 0.88; 95% CI, 0.81-0.96; P for heterogeneity < .001). A subgroup analysis showed protective effects in those receiving daily or weekly vitamin D without additional bolus doses (AOR = 0.81; 95% CI, 0.72-0.91) but not in those receiving one or more bolus doses (AOR = 0.97; 95% CI, 0.86-1.1); P for interaction = .05). Among those receiving daily or weekly vitamin D, protective effects were stronger in those with baseline 25-hydroxyvitamin D levels less than 25 nmol/L (AOR = 0.3; 0.17-0.53) than in those with baseline 25-hydroxyvitamin D levels 25 nmol/L or greater (AOR = 0.75, 0.6-0.95; P for interaction = 0.006). In addition, vitamin D did not impact the ratio of participants experiencing at least one serious adverse event (AOR = 0.98, 0.8-1.2, P = 0.83).
“Acute respiratory infections are responsible for millions of [ED] visits in the United States," Carlos A. Camargo, MD, department of emergency medicine, Massachusetts General Hospital, Boston, said in a press release. “These results could have a major impact on our health system and also support efforts to fortify foods with vitamin D, especially in populations with high levels of vitamin D deficiency."
There has been a growing body of evidence of the benefits of vitamin D. Healio Family Medicine recently compiled other research related to vitamin D detailing efficacy in patients with asthma, hip fracture and in lowering LDL cholesterol, while also outlining some of the negative health effects associated with vitamin D deficiency.
A study that appeared in JAMA late last year suggested that overall supplement use, such as vitamin D, remained stable, yet multivitamin and multimineral use declined during a recent 12-year period. – by Janel Miller
Disclosure: The researchers report no relevant financial disclosures.