High-dose vit D does not prevent falls in elderly

Not only is high-dose vitamin D supplementation of no help in preventing falls in older adults, it may raise safety concerns at doses ≥1,000 IU/day, according to the STURDY* trial.

As previous evidence on the role of vitamin D supplementation in preventing falls has been inconsistent, researchers set out to compare the effects of four different doses of vitamin D3 supplements on fall prevention.   

In the 2-stage, response-adaptive trial, 688 older adults aged ≥70 years (mean age 77.2 years) were randomized to receive one of the four doses of vitamin D3 supplements: 200 (control), 1,000, 2,000, or 4,000 IU/day during the dose-finding stage. [Ann Intern Med 2020;doi:10.7326/M20-3812]

Participants included had low serum vitamin D3 levels at baseline (25–72.5 nmol/L) and an elevated risk of fall, with 70 percent having either prefrail or frail status and 55.6 percent scoring ≤9 points on the Short Physical Performance Battery — reflecting a considerable degree of functional impairment.

During dose finding, the primary composite outcome of first fall or death occurred more frequently among participants who received the 2,000- or 4,000-IU/day dose than those on 1,000-IU/day dose (hazard ratios [HRs], 1.54 and 1.41; log-rank p=0.21). Hence, 1,000 IU/day was chosen as the best dose for subsequent confirmatory stage, with a posterior probability of being best of 0.90.

In the confirmatory study, participants initially on the two higher noncontrol doses were switched to the best-dose group of 1,000 IU/day.

Ultimately, there were no significant difference in the primary outcome between the 1,000-IU/day group and the control group receiving 200 IU/day (HR, 0.94; p=0.54) — suggesting no benefit from the higher dose supplementation.

“This finding supports guidelines, including those of the 2018 US Preventive Services Task Force, which reversed its 2012 recommendation and now does not recommend vitamin D supplementation for fall prevention in older persons without osteoporosis or vitamin D deficiency,” said the researchers.

“This trial further suggests a lack of benefit in persons with [low] 25-(OH)D levels of 25 to 72.5 nmol/L,” they added.

Not only was there no benefit, there was suggestion of harm associated with the higher dose: the rates of serious falls (HR, 1.87, 95 percent confidence interval [CI], 1.03–3.41) and falls with hospitalization (HR, 2.48, 95 percent CI, 1.13–5.46) were higher in the 1,000-IU/day group vs the control group.

“In the context of other reports of increased fall risk from high-dose supplemental vitamin D, policymakers should re-evaluate the upper dose limit considered safe, especially given the widespread use of vitamin D supplementation at or above 1000 IU/day,” the researchers noted.

One main limitation of the study was the use of the 200 IU/day dose as control rather than a placebo, in an attempt by the investigators to “first do no harm” in the study design by ensuring that the participants achieved the recommended daily allowance of vitamin D.

However, in doing so, the strategy prevents the modelling of frank vitamin D deficiency in real-world community-dwelling older adults, in whom the benefit from vitamin D supplementation may be most applicable, pointed out Dr Bruce Troen from the University at Buffalo Jacobs School of Medicine, Buffalo, New York, US, in an accompanying editorial. [Ann Intern Med 2020;doi:10.7326/M20-7609]

“The remaining question is, how can we prevent falls?” he continued. “The answer almost certainly will entail multicomponent approaches that include medication management, assessment of cognition and orthostatic blood pressure, exercise or physical therapy, disease management, vision care, home safety modifications, and possibly even vitamin D supplementation for certain patients.”

*STURDY: Study To Understand fall Reduction and vitamin D in You