SEATTLE — Calcium supplementation appears to reduce by 34% the 5-year risk of fracture among elderly women, according to the findings of a population-based study presented at the annual meeting of the American Society for Bone and Mineral Research.
The benefit was seen as early as 13 months despite the fact that all women were deemed at baseline to be getting adequate calcium—a mean of about 960 mg per day, said Richard Prince, M.D., of the department of endocrinology and diabetes at Sir Charles Gairdner Hospital, Perth, Australia.
“On the basis of these data, we believe that an increased emphasis on calcium supplementation should be a first-line, public-health approach to fracture prevention,” Dr. Prince said.
The 1,460 healthy ambulatory women, aged 70 or older, were randomly assigned to receive 600 mg of calcium carbonate twice daily or placebo.
Calcium intake was assessed and dual x-ray absorptiometry (DXA) scans were taken at baseline and again at least 1 year later.
Possible fractures were flagged on the basis of diaries that were submitted by the women every 4 months and were confirmed by x-ray.
During the 5-year study, the rates of death, withdrawal, and treatment cessation were similar between the two groups: 465 and 458 patients remained in the placebo and calcium groups, respectively.
In all, 235 individuals sustained 296 fractures; 118 fractures occurred among those taking calcium, and 178 occurred among those taking placebo, for an overall 34% reduction in fractures among patients in the calcium group who stuck to the protocol for the entire study period.
Upper-appendage fractures were most common.
Calcium appeared to improve bone mineral density at cortical bone sites, according to DXA findings.
At 13 months, there were early indications of a reduction in fracture rates among patients in the calcium group.
Calcium supplementation did not appear to have an effect on spinal bone mineral density or on the vertebral fracture rate.
Extrapolating from these findings, the data suggest that elderly women who use calcium supplementation, 1,200 mg daily, can cut their fracture risk from 16% to 10% over 5 years, Dr. Prince said.