High-dose vitamin D supplementation does not improve lower-extremity function and increases the risk for falls among elderly adults, a new study finds.
The results were published online January 4 in JAMA Internal Medicine by Heike A Bischoff-Ferrari, MD, DrPH, chair of the department of geriatrics and aging research at the University Hospital of Zurich, Switzerland, and colleagues.
In the randomized clinical trial of 200 men and women aged 70 or older who had experienced at least one low-trauma fall in the prior year, two high vitamin D doses monthly were compared with a standard dose of 24,000 IU of vitamin D3 per month (equivalent to the currently recommended 800 IU per day).
Subjects taking the higher doses showed no improvements in lower-extremity function and were more likely to have a second fall (P = .048) in the subsequent year.
"Contrary to our expectations, we found that participants in the standard dose of vitamin D [24,000 IU/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….Our data support the efficacy and safety of the monthly 24,000 IU supplementation for the correction of vitamin D deficiency in seniors age 70 and older," Dr Bischoff-Ferrari told Medscape Medical News.
In an accompanying editorial, Steven R Cummings, MD, of the California Pacific Medical Center Research Institute, San Francisco, and colleagues say that while there are data to support a recommendation for the use of 800-IU vitamin D daily and 1200-mg calcium supplementation in institutionalized older adults, "it is uncertain whether any dose of vitamin D supplementation reduces the risk of falls or fractures in community-dwelling older adults."
Moreover, Dr Cummings and his coauthors add, since the data also don't support the use of vitamin D supplements for other putative health benefits such as prevention of cardiovascular disease or cancer, "it is prudent to get recommended intakes of vitamin D and other vitamins from a balanced diet with foods that naturally contain what is manufactured into supplements."
But Dr Bischoff-Ferrari told Medscape Medical News, "We think that the editorial conclusion about not giving vitamin D at all is overstated," noting, "It is likely that many community-dwelling seniors have 25-hydroxyvitamin D levels close to the ideal range of 21 to 30 ng/mL and do not need further supplementation. However, about 50% of the world population are expected to be below this range and will likely benefit from supplementation."
Best Results With Standard Dose
In the single-center, double-blinded trial, the 200 subjects were randomized to receive either 24,000 IU of vitamin D3 given in a once-monthly 5-mL drink (equivalent to 800 IU per day) plus three placebo capsules once a month (controls); a 60,000-IU vitamin D3 monthly drink (equivalent to 2000 IU/day) plus three monthly placebo capsules; or a 24,000-IU vitamin D3 monthly drink plus two vitamin D3 capsules containing 12,000 IU each and one capsule containing 300 μg of calcifediol (the liver metabolite of the vitamin), once per month.
The primary outcome was the validated Short Physical Performance Battery (SPPB) score assessing lower-extremity function by walking speed, successive chair stands, and a balance test. The proportion of patients who achieved 25(OH)D levels of at least 30 ng/mL — the level recommended to achieve health benefits — was among the secondary outcomes.
The subjects had a mean age of 78 years, and two-thirds were female. All had reported a fall in the prior year. A total of 58% were vitamin D deficient (less than 20 ng/mL) at baseline.
After adjustment for baseline 25(OH)D level, age, sex, and body-mass index (BMI), the percentage of subjects who achieved 25(OH)D levels of at least 30 ng/mL was significantly higher at 12 months in the 60,000-IU and the 24,000-IU/calcifediol groups than the control 24,000-IU group (80.8% and 83.3% vs 54.7%, respectively, P = .001).
Mean SPPB scores did not differ among the treatment groups (P = .26), although there was less improvement in successive chair stands in the two high-dose groups compared with the standard 24,000-IU dose.
During the 12 months, 60.5% of the 200 subjects fell. There were significantly more who fell among the two higher-dose vitamin D groups — 66.9% with the 60,000-IU dose and 66.1% with 24,000/calcifediol dose vs just 47.9% with the standard 24,000-IU dose (P = .048). The mean number of falls were 1.47, 1.24, and 0.94, respectively (P = .09).
The seniors who were not vitamin D deficient at baseline had the greatest increase in falls at the 60,000-IU dose (mean, 1.65; P = .02 vs the standard 24,000-IU group).
Those With Highest Vitamin D Had Five Times the Risk of Falling
Participants who reached the highest quartile of 25(OH)D level (44.7–98.9 ng/mL) at the 12-month follow-up had a 5.5-fold higher odds of falling compared with those reaching the lowest quartile (21.3 to 30.3 ng/mL) (P < .001).
Dr Bischoff-Ferrari told Medscape Medical News that there may be a therapeutic range for vitamin D with respect to fall prevention among seniors who had a prior fall, noting, "In fact, our study points to the range between 21 to 30 ng/mL as optimal because both 25-hydroxyvitamin D blood levels below 21 ng/mL and above 45 ng/mL were associated with increased risk of falling."
Alternatively, she said, monthly doses of vitamin D may not be advantageous at the higher dose used in this study.
"The physiology behind a possible detrimental effect of a high dose of vitamin D monthly or less frequently on muscle function and falls remains unclear and needs further investigation."
Dr Bischoff-Ferrari reported receiving speaker fees from and serving on advisory boards for Merck Sharp & Dohme, Amgen, WILD, DSM Nutritional Products, Roche Diagnostics, Nestlé, Pfizer, and Sanofi; the coauthors had no relevant financial relationships, nor did the editorialists.
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Cite this: High-Dose Vitamin D Supplementation Ups Elderly Fall Risk - Medscape - Jan 04, 2016.