August 27, 2019
1 min read

Vitamin D supplementation does not prevent acute respiratory infections

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Monthly high-dose vitamin D supplementation does not prevent acute respiratory infections in older adults with vitamin D deficiency, according to a recent study.

“Acute respiratory infections (ARIs) are common and have public health impact. While most ARIs are self-limited viral illnesses, they can be fatal, particularly in high-risk groups such as infants and older adults,” Carlos A. Camargo Jr., MD, DrPH, professor in the Department of Emergency Medicine at Massachusetts General Hospital, Harvard Medical School, and colleagues wrote. “For more than a decade, many studies have linked low vitamin D status with increased risk of ARI. Vitamin D status is best measured with blood levels of 25-hydroxyvitamin D (25OHD). In recent years, randomized controlled trials have investigated the role of vitamin D supplementation in ARI prevention. While some studies have shown substantial benefit, others have not.”

Between 2011 and 2012, researchers performed a randomized, double-blinded, placebo-controlled trial of 5,110 adults aged 50 to 84 years. All participants received an initial oral dose of 200,000 IU vitamin D3, followed by 100,000 IU monthly (n = 2,558) or placebo (n = 2,552) until late 2013 to determine if supplementation would have a positive impact on ARIs.

Data from the study showed that the mean age of participants was 66 years, 58% were male and mean baseline blood 25OHD level was 63 (24) nmol/L. Results showed that vitamin D supplementation increased mean 25OHD to 135 nmol/L at 3 years, whereas those on placebo stayed at 63 nmol/L. During follow-up, 3,737 participants reported at least one ARI, 74.1% in the vitamin D group vs. 73.7% in the placebo group, according to the study.

“This population-based [randomized clinical trial] of [more than] 5,000 older adults showed that monthly high-dose vitamin D supplementation did not prevent ARI. One subgroup (current smokers) showed benefit but this isolated finding requires replication. More importantly, further study is needed to determine whether the effects of daily or weekly dosing differ,” the authors concluded.

The authors added that while further trials are being completed, they do not recommend monthly dosing of vitamin D for the prevention of ARI. – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.