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Higher monthly vitamin D doses associated with increased fall risk

Monthly high doses of vitamin D produce no benefit to lower extremity function, and are associated with a higher risk for falls among patients 70 years and older who have prior falls, according to a study published in JAMA Internal Medicine.

“Current evidence from double-blind clinical trials among seniors aged 65 and older support the correction of vitamin D deficiency with the current recommendation of 800 IU vitamin D per day (equivalent to our monthly dose of 24,000 IU) for fall and fracture prevention,” Heike A. Bischoff-Ferrari, MD, DrPH, chairman of the department of geriatrics and aging research at the University Hospital of Zurich and the University of Zurich, Switzerland, and colleagues wrote in supplemental comments. “However, if and to what extent higher doses of vitamin D are beneficial has not been studied conclusively.”

To determine the effectiveness of higher doses of vitamin D at improving lower extremity function and lowering the risk for falls, the researchers conducted a 1-year, double-blind, randomized clinical trial, with 200 participants aged 70 years and older, all with previous falls. Participants were assigned to one of three monthly treatments of vitamin D: 24,000 IU of vitamin D3 per month (n=67); 60,000 IU of vitamin D3 per month (n=67); or 24,000 IU of vitamin D3 plus 300 g of calcifediol per month (n=66).

The screening phase was Dec. 1, 2009 to May 31, 2010, with the last study visit occurring in May 2011. Researchers conducted their analysis from June 15, 2012 to Oct. 10, 2015. The primary endpoint was improving lower extremity function and achieving 25-hydroxyvitamin D levels of at least 30 ng/mL at 6 months and 12 months. A secondary end point was monthly reported falls. Analyses were adjusted for age, sex and BMI.

The two higher monthly doses — 60,000 IU and 24,000 IU plus calcifediol — were more likely to result in 25-hydroxyvitamin D levels of at least 30 ng/mL (P = .001). However, they had no benefit on lower extremity function, and more participants in these groups experienced falls. Of all 200 participants, 61% fell during the 12-month follow-up period. In the 24,000 IU group, 48% fell, whereas 67% fell in the 60,000 IU group and 66% fell in the 24,000 IU plus calcifediol group (P = .048). The 24,000 IU group had the least mean number of falls, 0.94, compared with 1.47 in the 60,000 IU group, and 1.24 in the 24,000 IU plus calcifediol group.

“Based on our small pilot trial among young postmenopausal women, we expected a great gain in lower extremity function with the higher dose groups, and also expected a greater reduction in falls among these groups,” Bischoff-Ferrari and colleagues wrote in supplemental comments. “However, contrary to our expectations, we found that participants in the standard dose of vitamin D (24,000 IU per month) had the best improvement in lower extremity function, the lowest odds of falling and the fewest number of falls compared with the two high-dose groups.” – by Jason Laday

Disclosure: Bischoff-Ferrari reports receiving speaker fees from, and serving on advisory boards for Amgen, DSM Nutritional Products, Merck Sharp & Dohme AG, Nestlé, Pfizer, Roche Diagnostics, Sanofi and WILD. No other author reported any relevant financial disclosures.