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Posted By: Richard S. Pope, PA-C, MPAS
December 24, 2019
Lower extremity functional decline in our elderly population is a major risk factor for falls, hip fracture, frailty, and loss of autonomy. As the baby boomer generation ages, an increasing segment of our population is now subject to these impairments. A group of investigators has been looking into the causes of functional decline in older age and has hypothesized that vitamin D deficiency may be a significant factor. In particular, one randomized controlled trial in Switzerland that ran from December 2009 to May 2011 enrolled a study cohort comprised of 200 men and women aged 70 and older (mean age 78) who had fallen once in the last year, signaling increased risk of decline to frailty. Those using walkers, canes, or other assistive devices were excluded, and all participants had to be community dwelling and capable of using public transportation.
Hypothesizing that dosing vitamin D3 at 60,000 IUs monthly would improve compliance, reduce falls, improve muscle strength, prevent fractures, and slow the decline to frailty, the study comprised three groups. The first was given 60,000 units of vitamin D3 monthly, equivalent to 2,000 IUs daily, which is recommended by some societies and foundations. The second group was given 24,000 IUs of vitamin D3 and 300 mcg of calcifediol (which is 2 to 3 times more potent and a liver metabolite of vitamin D) monthly. The control group was given a monthly dose of 24,000 IUs of vitamin D3 alone. No group was supplemented with calcium aside from receiving education on calcium rich foods.
The primary endpoint of the trial evaluated lower extremity function by using a short physical performance battery (SPPB) that consisted of walking speed, successive chair stands, and a balance test—all of which have been well validated. Additionally, 25-hydroxy-vitamin D (25[OH]D), calcium, and intact parathyroid hormone (iPTH) levels were monitored. There were no safety signals in any of the three arms of the study.
The conclusions of the study with regard to falls were not expected. The experimental groups with high monthly dosing of vitamin D demonstrated the most falls compared to the control group. More specifically, the 60,000 IU group had a 66.9% chance of fall during the 12-month study, while the 24,000 IU plus calcifediol group had a 66.1% chance of fall. Interestingly, the control group had significantly lower percentages of fallers, with a 47.9% chance of fall.
Additionally, the higher-dose vitamin D3 cohort experienced no improvement in lower extremity function as measured by the SPPB evaluation. However, the percentage of participants who achieved 25(OH)D levels of at least 30 ng/mL was significantly greater in the two high-dose vitamin D groups when compared with the control group.
The findings suggested that those who reached the highest quartile of 25(OH)D at both 6 and 12 months were at higher risk of falling. No one in the control group reached the highest quartile at either time period. The physiologic mechanism by which this increased fall rate occurred is not known. It was suggested that high-dose monthly vitamin D may have led to increased physical activity, and thereby the opportunity to fall. However, further analysis by the researchers suggested that this theory did not explain their findings. So, at this point the trial supports lower dose over high-dose vitamin D supplementation as it relates to falls in those who are ≥70 years old. Future studies will continue to define best practices for vitamin D supplementation in our older population.
- Bischoff-Ferrari HA, Dawson-Hughes B, Oray EJ, et al. Monthly high-dose vitamin D treatment for the prevention of functional decline: a randomized clinical trial. JAMA Intern Med. 2016;176:175-183.
- Cummings SR, Nevitt MC. Non-skeletal determinants of fractures: the potential importance of the mechanics of falls. Study of Osteoporotic Fractures Research Group. Osteoporos Int. 1994;4(Suppl 1):67-70.
- Fried LP, Tangen CM, Walston J, et al. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56:M146-156.
- Guralnik JM, Simonsick EM, Ferrucci L, et al. A short physical performance battery assessing lower extremity function: association with self-reported disability and prediction of mortality and nursing home admission. J Gerontol. 1994;49:M85-94.
- Tinetti ME, Williams CS. Falls, injuries due to falls, and the risk of admission to a nursing home. N Engl J Med. 1997;337:1279-1284.