Vitamin D and Calcium Supplementation in Older Adults
A randomized trial found no effect on cancer or vascular mortality.
Intense interest surrounds the idea that vitamin D supplementation can prevent just about any disease under the sun (no pun intended). To address this issue, U.K. researchers present new findings from a previously published trial of vitamin D and calcium supplementation. Nearly 5300 patients (age, 70) with previous fractures were randomized to receive vitamin D3 (800 IU daily), calcium (1000 mg daily), both, or placebo. During 2 to 5 years of treatment, neither vitamin D nor calcium lowered rates of new fractures (JW Gen Med Jun 10 2005).
Now, these researchers have examined nonfracture outcomes that occurred during the trial plus 3 more years of follow-up; the additional follow-up was added because clinically evident effects on cancer and cardiovascular disease might be delayed. During a median follow-up of 6 years, neither vitamin D nor calcium was associated with significantly higher or lower overall mortality, cancer mortality, cancer incidence, or vascular mortality (compared with placebo).
Comment: This study population was limited to elders with previous fractures, duration of treatment was only a few years, baseline serum 25-hydroxyvitamin D levels were low (about 15 ng/mL), and the 800-IU supplement increased serum levels by only about 10 ng/mL. However, vitamin D and calcium trials have been performed in various other populations; the authors review that literature and conclude that no decisive evidence yet exists to support a beneficial effect of vitamin D or calcium supplementation on vascular or cancer risk.
Allan S. Brett, MD
Published in Journal Watch General Medicine March 13, 2012