What Role Does Vitamin D Play in Reducing Respiratory Infections in Older Adults?

Though unpleasant, acute respiratory infections (ARIs), such as the common cold, can be easily managed for most individuals with the proper treatment; however, for those 65 years and older who are living in long-term care (LTC) facilities, these infections pose a much greater risk.

Because this population tends to have weakened immune systems, researchers are looking for ways to strengthen immune system function in order to stave off these harmful infections. To this end, researchers at the American Geriatrics Society have chosen to take a closer look at the role vitamin D might play in reducing the number of ARIs experienced by older adults residing in LTC facilities.

According to study authors, “Vitamin D has an important role in many aspects of immune function, particularly innate immunity. Older adults are at high risk of vitamin D deficiency, and epidemiological studies demonstrate a consistent association between vitamin D deficiency and ARI, but clinical trials of vitamin D supplementation for ARI prevention have been mixed, with meta-analyses suggesting modest benefit but substantial heterogeneity.”

Additionally, the authors noted that falls are “an important cause of morbidity” in the elderly, which is why the role that vitamin D might play in preventing falls has been of great interest to researchers. In fact, “an American Geriatrics Society consensus statement recommends 1,000 to 4,000 IU daily of vitamin D supplementation for fall prevention in older adults.”

Taking this information into account, researchers decided to conduct a study that would determine if high doses of vitamin D, administered on a monthly basis, could safely and effectively prevent ARI in older individuals living in LTC facilities and positively impact the rate of falls.

Their study, published in the Journal of American Geriatrics Society, was comprised of 107 participants, all of whom were 60 years of age or older, and living in LTC facilities throughout Colorado. The researchers divided the participants into two groups: the “high-dose group” and the “standard-dose group.” Those in the high-dose group were already receiving zero to 1,000 International Units (IUs) of vitamin D each day and received an additional dose of vitamin D, once a month, of 100,000 IU. Those in the standard-dose group were given a placebo once a month, “depending on how much vitamin D they took daily or monthly,” according to the press release.

In the follow-up period (12 months), the researchers kept track of the number of ARIs (common colds, middle ear infections, influenza, pneumonia, among others) in each individual that called for medical attention. The researchers also kept track of the number of “falls, fractures, kidney stones, hospitalizations, and deaths” that occurred during the period of study.

Upon conclusion of the study, the researchers found that compared to those in the standard-dose group, those individuals who were a part of the high-dose group experienced 40% less ARIs in the follow-up period. However, those in the high-dose group were also noted to have experienced an increased number of falls than their standard-dose counterparts. In an attempt to provide explanation for the increased number of falls, the study authors wrote, “The mechanism of this finding requires further investigation including exploration of the hypothesis that high-dose vitamin D leads to greater mobility, resulting in greater exposure to falls.”

According to the researchers, future studies are needed in order to ascertain if daily doses of vitamin D, rather than monthly doses, may better assist in ARI prevention among older individuals living in LTC facilities, as well as the correlation between vitamin D dosing and falls.