Vitamin D Calcium Supplements Don't Cut Fracture Risk for Elderly
Two large U.K. studies seem to reverse conventional wisdom
WEDNESDAY, April 27, 2005 (HealthDayNews) -- Vitamin D and calcium supplements appear to have no effect in preventing elderly people from getting fractures, according to the results of two major studies released Wednesday night.
The findings are particularly important because elderly people, especially those with osteoporosis, have a high risk of bone fractures, and earlier research has shown that these supplements cut that risk.
The latest news comes out of separate, randomized controlled trials done in the United Kingdom involving more than 8,500 people over the age of 70.
In one study of 5,292 people, all of whom had had one fracture already, researchers led by University of Aberdeen professor Adrian Grant found that vitamin D and calcium didn't help prevent a second fracture.
"For people who have already had a fracture, calcium and vitamin D separately or together don't seem to be enough to prevent them from having a further fracture," said study co-author Dr. Frazer Anderson, a senior lecturer in geriatric medicine at the University of Southhampton.
Those findings appear in the April 27 online issue of The Lancet.
In the second study, out of the University of York, researchers tracked 3,314 women aged 70 and older who were at risk for hip fractures and found the supplements were also no help.
"Just like The Lancet study, there was no reduction in hip fractures with either calcium or vitamin D," said study author David J. Torgerson, a professor of health sciences at the university. That set of findings is published in the April 30 issue of the British Medical Journal.
For The Lancet study, 5,292 people aged 70 or older from 21 hospitals across the United Kingdom who had had a fracture were assigned to take vitamin D alone or vitamin D plus calcium or calcium alone. In addition, members in each group were given dummy pills instead of calcium or vitamin D. The groups were then tracked for between 24 and 62 months.
The researchers found that 13 percent of the patients had a new fracture. For people in the group taking calcium, the fracture rate was 12.6 percent, compared with 13.7 percent of those taking a dummy pill. For those taking vitamin D alone, the fracture rate was 13.3 percent, compared with 13.1 percent for those taking the dummy pill. And for those taking both calcium and vitamin D, the fracture rate was 12.6 percent, compared with 13.4 percent for those taking the dummy pill.
Based on these findings, Anderson is convinced that supplements don't offer protection from second fractures. "We are confident that if there is a benefit to calcium and vitamin D in those people, it's a small one and too small for us to find," he said.
The real message of this study, he added, is that giving calcium and vitamin D to older people who have had a fracture isn't enough.
"Those people need to be investigated for osteoporosis, and if they've got it, they need to be treated specifically for osteoporosis," he said.
The dietary supplement industry took issue with the findings.
"There are hundred of studies that show the benefit of vitamin D and calcium supplements on improving bone density," said Andrew Shao, vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a lobbying group for the industry. "Consumers and the media shouldn't leap to the conclusion that these supplements aren't good for them based on this one study."
Another expert sees nothing dramatically new in The Lancet study. "I am not surprised," said Dr. Steven J. Goldstein, a professor of obstetrics and gynecology at New York University Medical Center. "By definition, the people they studied here had osteoporosis."
"We know that vitamin D and calcium alone are not sufficient to treat osteoporosis," Goldstein added. "All this study showed is that if you take people who have already suffered a fracture, who therefore by definition have osteoporosis, and you simply treat them with calcium and vitamin D, it's not sufficient. You've already let the horse out of the barn."
But Goldstein cautioned that this study should not diminish the importance of vitamin D and calcium to prevent bone loss. By building bone mass when you are young, you have a better chance of preventing osteoporosis as you age, he said.
"You have to be very careful not to extrapolate any of this data to the importance of adequate calcium and vitamin D in people's diets for a lifetime who are not already elderly with a history of a previous fracture," Goldstein said.
In the British Medical Journal study, involving 3,314 women at risk for hip fractures, the York researchers gave some women vitamin D and calcium and a leaflet on diet and how to avoid falls. Others were given only the leaflet.
After 25 months, the researchers found that about 1 percent of women in both groups suffered a hip fracture.
Torgerson agrees that vitamin D and calcium alone won't treat osteoporosis. "If you are at risk for osteoporosis, you need to take a treatment that is better than calcium and vitamin D," he said. "If you are at risk for a hip fracture, using just calcium and vitamin D supplements isn't going to help you."
The York findings appear at odds with another British study published two years ago in the British Medical Journal. In that one, University of Cambridge researchers tracked 2,686 people aged 65 and older over a five-year period, and found that slow-release vitamin D supplements given four times a year cut the risk of fractures by 22 percent.
The National Institutes of Health can tell you more about osteoporosis.