For elderly patients, higher monthly doses of vitamin D do not improve lower extremity function and may increase the risk of falls compared with lower monthly doses, according to a study published in JAMA Internal Medicine.
Although participants given high doses of vitamin D were more likely to achieve 25-hydroxyvitamin D (25[OH]D) levels of ≥30 ng/mL, they did not show improved lower extremity function compared with the control group, reported Heike A. Bischoff-Ferrari, MD, DrPH, and colleagues.
A previous study had linked higher levels of 25(OH)D to an increased likelihood of maintained or improved lower extremity function. Because impaired lower extremity function is a major risk factor for falls, the researchers wanted to determine if vitamin D dosages (or vitamin D plus calcifediol) could increase levels of 25(OH)D to ≥30 ng/mL and thereby increase the risk of falls.
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The study included 200 participants aged ≥70 years (mean age, 78) who had experienced a prior fall, 116 of whom had vitamin D deficiencies at baseline. Participants were randomized to 1 of 3 groups: a control group receiving 24,000 IU of vitamin D once per month, a group receiving 60,000 IU of vitamin D once per month, and a group receiving 24,000 IU of vitamin D plus 300 μg of calcifediol once per month.
The researchers measured changes in lower extremity function using the participants’ Short Physical Performance Battery (SPPB) scores measured at baseline and at 6 and 12 months of follow-up.
Compared with the 24,000 IU of vitamin D group, participants in the other 2 groups were significantly more likely to achieve 25(OH)D levels of ≥30 ng/mL. However, no significant difference was observed in the mean SPPB score changes among the 3 groups. In 1 of 3 SPPB score components (in which a person must complete 5 successive chair stands), both the 60,000 IU of vitamin D and the calcifediol groups showed less improvement compared with the 24,000 IU vitamin D group.
During the 12-month follow-up period, 121 of 200 participants had a fall. The incidence of falls was similar in both high-dose treatment groups—66.9% in the 60,000 IU of vitamin D group and 66.1% in the calcifediol group. Participants in these groups had a significantly higher risk of falling compared with those in the 24,000 IU of vitamin D group, in which 47.9% of participants fell.
“A theoretical possibility has been raised that periodic administration of high doses of vitamin D accounts for the increased risk of falls and fractures,” Steven R. Cummings, MD, and colleagues wrote in a related editorial. “That hypothesis should be tested by placebo-controlled trials showing that a daily dose of 2000 IU, for example, reaching serum 25(OH)D levels of at least 30 ng/mL reduces the risk of falls and fractures.”
References
- Bischoff-Ferrari HA, Dawson-Hughes B, Orav EJ, et al. Monthly High-Dose Vitamin D Treatment for the Prevention of Function Decline: A Randomized Clinical Trial. JAMA Intern Med. 2016; doi:10.1001/jamainternmed.2015.7148.
- Cummings SR, Kiel DP, Black DM. Vitamin D Supplementation and Increased Risk of Falling: A Cautionary Tale of Vitamin Supplements Retold. JAMA Intern Med. 2016; doi:10.1001/jamainternmed.2015.7568.
