High Doses of Vitamin D May Increase Risk for Falls

SEATTLE — High doses of vitamin D, including those recommended in some clinical guidelines, may in fact lead to an increased risk for falls in elderly women, according to new data.

“The dose of 4000 IU of vitamin D a day recommended by the American Society of Geriatrics is actually dangerous for the patients and increasing the fall rate, not decreasing the fall rate,” said study investigator J. Christopher Gallagher, MD, who is professor of medicine and director of the Bone Metabolism Unit in the division of endocrinology at Creighton University School of Medicine in Omaha, Nebraska.

In their study, Dr Gallagher and colleagues analyzed the fall rate and physical performance tests in a group of 163 women (mean age, 66.2 years; mean BMI, 30.3) in a vitamin D dose-ranging study.

All women were enrolled in a 1-year, double-blind, randomized study of calcium plus daily vitamin D 400 IU, 800 IU, 1600 IU, 2400 IU, 3200 IU, 4000 IU, 4800 IU, or placebo.

Compliance rates were high, and blood tests were taken every 3 months.

A total of 147 women completed the study, 49% of whom experienced a fall. The researchers noted that the fall rate was higher in women with a history of falls in the last year compared with those with no fall history.

Overall, there was no effect of the pooled vitamin D dose on falls. However, when patients were categorized into low-dose (400 IU-800 IU), medium-dose (1600 IU-3200 IU), or high-dose (4000 IU-4800 IU) groups, the researchers found that there were significant differences.

A U-shaped curve emerged when analyzing fall rates according to dose. Results showed that low doses of vitamin D had no effect on falls, as compared with placebo. On the other hand, medium doses were associated with a significant decrease in falls, while high doses were associated with a significant increase in falls.

Currently, the American Geriatrics Society consensus statement recommends a daily vitamin D intake of 4000 IU daily from all sources, according to Dr Gallagher. Even so, he said there are no strong data to support the recommendation.

“It is in their guidelines with no justification,” Dr Gallagher said in an interview with Endocrinology Advisor. “We did a dose-response study. We saw a reduction in falls optimized at a dose of around 2000 IU per day.”

The researchers found that 100% of the women with a previous fall history on high doses of vitamin D experienced a fall. They also noted a nonsignificant decline in all physical performance tests in all of the vitamin D dose groups.

These findings may come as a surprise to many clinicians, said Shervin Yousefian, MD, who presented the data at the American Society for Bone and Mineral Research (ASBMR) 2015 Annual Meeting.

“We saw when looking at the studies that there has been a controversy. In previous studies, some showed increased falls but some showed improvement,” Dr Yousefian told Endocrinology Advisor. “But you need to see how different doses would affect the fall rate and also the physical performance.”

ASBMR President Douglas P. Kiel, MD, MPH, said this study is interesting, noting that providing patients with a calendar to track their falls is the optimal way to evaluate falls because it is much more accurate than having patients recall falls at periodic clinic visits.

“The best method of looking at falls is to require a monthly calendar and have [patients] mark their calendars on the day they fall. They were queried at 3-month intervals [in this study],” Dr Kiel said in an interview with Endocrinology Advisor.

References

1. Yousefian S. Abstract LB-SU0027: Falls are increased on Recommended Doses of Vitamin D in Elderly Women. Presented at: American Society for Bone and Mineral Research (ASBMR) 2015 Annual Meeting; Oct. 9-12, 2015; Seattle.
2. American Geriatrics Society Workgroup on Vitamin D Supplementation for Older Adults. Recommendations Abstracted from the American Geriatrics Society Consensus Statement on Vitamin D for Prevention of Falls and Their Consequences.  J Am Geriatr Soc. 2014;62(1):147-152.