The effects of vitamin D supplementation on types of falls

Abstract

Background/objectives: To assess whether vitamin D supplementation prevents specific fall subtypes and sequelae (e.g., fracture).

Design: Secondary analyses of STURDY (Study to Understand Fall Reduction and Vitamin D in You)-a response-adaptive, randomized clinical trial.

Setting: Two community-based research units.

Participants: Six hundred and eighty-eight participants ≥70 years old with elevated fall risk and baseline serum 25-hydroxyvitamin D levels of 10-29 ng/ml.

Intervention: 200 IU/day (control), 1000 IU/day, 2000 IU/day, or 4000 IU/day of vitamin D3.

Measurements: Outcomes included repeat falls and falls that were consequential, were injurious, resulted in emergency care, resulted in fracture, and occurred either indoors or outdoors.

Results: After adjustment for multiple comparisons, the risk of fall-related fracture was greater in the pooled higher doses (≥1000 IU/day) group compared with the control (hazard ratio [HR] = 2.66; 95% confidence interval [CI]:1.18-6.00). Although not statistically significant after multiple comparisons adjustment, time to first outdoor fall appeared to differ between the four dose groups (unadjusted p for overall difference = 0.013; adjusted p = 0.222), with risk of a first-time outdoor fall 39% lower in the 1000 IU/day group (HR = 0.61; 95% CI: 0.38-0.97; unadjusted p = 0.036; adjusted p = 0.222) and 40% lower in the 2000 IU/day group (HR = 0.60; 95%CI 0.38-0.97; p = 0.037; adjusted p = 0.222), each versus control.

Conclusion: Vitamin D supplementation doses ≥1000 IU/day might have differential effects on fall risk based on fall location and fracture risk, with the most robust finding that vitamin D doses between 1000 and 4000 IU/day might increase the risk of first time falls with fractures. Replication is warranted, given the possibility of type 1 error.

Keywords: fall reoccurrence; indoor; outdoor; randomized clinical trial; vitamin D dose.

Figure 1.. Accumulation of falls over all follow-up of all 688 randomized participants by type of fall.

Each pair of lines shows the accumulation of the specified type of fall as the falls occurred in the months after randomization by treatment group. Pooled Higher Doses includes participants randomized to 1000, 2000, or 4000 IU/day. A fall was consequential if any injury was sustained or any medical care was sought. A fall required emergency care if the participant sought care from an urgent care center, emergency department or hospital. A fall was injurious if the participant sustained any injury (e.g., bruising, sprain, fracture, etc). A fall with fracture was a fall with fracture of any body part.