High doses of vitamin D do not help improve the lower extremities' muscle strength in older people aged 70 and above. On the contrary, it increases their risk for falls, according to a new study conducted by researchers from University Hospital Zurich.
Weak leg muscles increase older people's risk of falling. To help improve and delay the weakening of their leg muscles, taking vitamin D supplements has been recommended. However, not enough data supports this recommendation, according to a press release.
The researchers investigated the effect of higher doses of vitamin D on the lower extremities. They recruited 200 study participants, both men and women ages 70 or older, who have had previous falling problems. Fifty-eight percent of them were vitamin D deficient at the start of the study.
The participants were divided into three groups, with 67 people for the first group, 67 people for the second group and 66 people for the third group.
The first group was given a monthly dose of 24,000 IU vitamin D3 and served as control. The second group was given a monthly dose of 60,000 IU vitamin D3. The third group was given a monthly dose of 24,000 IU vitamin D3 coupled with calcifediol.
At the end of 12 months, the researchers found that those who were given 60,000 IU vitamin D3 and 24,000 IU vitamin D3 plus calcifediol did not have better leg function, even if their 25-hydroxyvitamin D level reached at least 30 ng/mL.
Interestingly, more people from these two groups experienced falling. The researchers recorded that 66.9 percent from the high-dose vitamin D3 group and 66.1 percent from the vitamin D3 and calcifediol combination group fell, while only 47.9 percent from the control group fell.
"Compared with a monthly standard-of-care dose of 24,000 IU of vitamin D3, two monthly higher doses of vitamin D (60,000 IU and 24,000 IU plus calcifediol) conferred no benefit on the prevention of functional decline and increased falls in seniors 70 years and older with a prior fall event," the researchers wrote.
They emphasized that high doses of vitamin D or vitamin D and calcifediol combination "may not be warranted" in older people with previous fall experience because of their "potentially deleterious effect."
"The strategy of supplementation with vitamin D to achieve serum levels of at least 30 ng/mL has not been established by RCTs [randomized clinical trials] to reduce the risk of falls and fractures. It may increase the risk of falling," a group of researchers wrote in an accompanying editorial.
The study was published online Jan. 4 in JAMA Internal Medicine.
