High-dose vitamin D does not prevent falls among older adults
Among older adults with an elevated fall risk and low serum 25-dydroxyvitamin D levels, daily vitamin D3 supplementation at doses of 1,000 IU did not prevent falls compared with a 200 IU dose, according to a randomized clinical trial.
Several analyses also raised safety concerns about daily vitamin D3 doses of 1,000 IU or higher, researchers said.
“Our trial reinforces the fact that there is very little evidence to support high-dose vitamin supplements of any type to improve health,” Lawrence J. Appel, MD, MPH, the director of the Welch Center for Prevention, Epidemiology and Clinical Research at Johns Hopkins University, told Healio Primary Care. “More is not always better, and may even be worse.”
In the trial, nearly 700 older adults (mean age, 77.2 years) took a daily dose of either 200 IU (control group), 1000 IU, 2000 IU or 4000 IU of vitamin D. All the adults had an elevated fall risk; 56.4% were men and 18.2% were Black. The mean serum 25-hydroxyvitamin D (25-(OH)D) level was 55.3 nmol/L.
The study’s primary outcome was time to first fall or death over 2 years.
Appel and colleagues reported that the primary outcome rates were highest among adults who received the 2,000 IU and 4,000 IU doses rather than the 1,000 IU dose. Consequently, the 1,000 IU dose was selected as the “best dose” (posterior probability of being best = 0.90), according to the researchers. After participants who took the highest doses scaled back to 1,000 IU, the primary outcome was not significantly different compared with those who took 200 IU. An analysis of falls with adverse outcomes suggested the risk was greater among those in the 1,000 IU cohort vs. the 200 IU cohort. Specifically, serious falls — those resulting in a fracture or dislocation or requiring hospitalization, for example — had an HR of 1.87 (95% CI, 1.03-3.41), and falls with hospitalization had an HR of 2.48 (95% CI, 1.13-5.46).
Appel said the findings, along with other “inconsistent evidence” in this clinical area, warrant considering if “the upper limit of vitamin D intake considered safe should be revised.” He encouraged clinicians to download brochures from CDC’s website and distribute them to their older patients.
In a related editorial, Bruce R. Troen, MD, the division chief of geriatrics and palliative medicine at the University at Buffalo Jacobs School of Medicine & Biomedical Sciences, commended Appel colleagues’ “well-executed effort” to determine whether high-dose vitamin D supplementation prevents falls, but he questioned the study’s methodology.
“The investigators’ commitment to ‘first do no harm’ by providing the control group with 200 IU [per day] of vitamin D is commendable, but does this strategy prevent the modeling of real-world scenarios — such as frank vitamin D deficiency — in which community-dwelling older adults might realize benefits?” Troen asked. “The answer is important because older adults with greater insufficiency or frank deficiency, particularly those with 25-(OH)D levels of 25 nmol/L or less, may be those most likely to benefit from vitamin D supplementation.”
He also noted that the study lacked information on study participants’ comorbid medical conditions, medications that increase fall risk and the methods used to assess cognitive impairment and frailty.