Calcium, vitamin D combo reduces bone loss, fracture rate for older people
Supplements of calcium and vitamin D can significantly reduce bone loss and the risk of fractures in older people, according to a new report from scientists at Tufts University. The research, the first to show that these supplements can help older men fight osteoporosis, also demonstrates that the benefits of these low cost and easily available supplements can be maintained over several years.
The findings by Bess Dawson-Hughes*, M.D., and colleagues of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University appear in the September 4, 1997, The New England Journal of Medicine . The research was funded by the National Institute on Aging (NIA) as part of its STOP/IT (Sites Testing Osteoporosis Prevention/Intervention Treatments) initiative.
"Older people can benefit from this therapy at essentially no risk and at low cost," said Dawson-Hughes. "Our research underscores the importance of calcium and vitamin D supplementation in helping healthy and active older people stay that way."
NIA scientists noted the importance of the finding for older men. "Until recently, osteoporosis has been considered to be a women's problem," said Sherry Sherman, Ph.D., Director, Clinical Endocrinology and Osteoporosis Research, NIA, and project officer for the study. "We know that older men do experience considerable bone loss over time. With older people living longer than ever, increasing the intake of calcium and vitamin D can be an important lifelong strategy for both sexes."
The researchers chose a combination of calcium and vitamin D to take advantage of the vitamin's influence in helping the body absorb and utilize calcium. As people age, the absorption of calcium and, it is believed, vitamin D, declines, as does production of vitamin D by the skin. This reduced ability to absorb calcium contributes to bone loss as people age, and low bone density is an underlying cause of increased hip fracture among the elderly.
The amounts of calcium and vitamin D used in the study are in keeping with recent recommendations of a National Academy of Sciences (NAS) panel, which recommended changes in current dietary requirements for calcium and related nutrients. The NAS group suggested that people over 50 increase their daily intake of calcium to about 1,200 milligrams and found that about 400 - 600 International Units of vitamin D (cholecalciferol) would be adequate.
Dawson-Hughes followed 389 men and women age 65 and older for 3 years. The study participants kept to their usual diets, in which they were generally getting the old recommended dietary allowances of calcium and vitamin D. At bedtime, about half of the study participants took placebo pills of no nutritional value. The other half took two separate pills, one containing 500 milligrams of elemental calcium (calcium citrate malate) and the other 700 International Units of vitamin D. All participants visited Tufts every 6 months for measurements of bone mineral density and other tests. Researchers also noted the number of fractures that occurred during the study period.
Over the 3 years, the calcium/vitamin D group lost significantly less total body bone, and, in some areas, gained bone mineral density. In men, where the findings were more pronounced, those taking placebos lost about one percent of their bone density at the hip over 3 years. Men taking the calcium/vitamin D combination increased their bone density by about 1 percent. The benefit at the hip for men, therefore, totaled a 2 percent improvement in bone density for the supplemented group. For women, the positive effects were most notable in the total body bone density, with lesser effects at the hip and spine.
In addition, the supplements may be effective in maintaining the skeleton over the long term, Dawson-Hughes said. The researchers found that the supplements were beneficial to bone density at the hip, spine, and total body in the first year, and further improved bone density of the total body during the second and third years of the study. The initial effects of supplementation at the hip and spine during the first year held steady, but did not change appreciably, over the next two years.
Even small losses of bone mass each year are important, scientists say. The losses are cumulative and add up to significant decreases in bone mineral density over time. "If we could retard bone loss in older people, we could make a lot of headway in preventing the devastation of osteoporosis and the fractures that commonly come with it," said Sherman.
The group taking supplements did considerably better in avoiding fractures. Some 5.9 percent of the participants taking the calcium and vitamin D suffered fractures, compared with 12.9 percent who did not take the supplements. Most of the fractures occurred in women.
Some 28 million middle-aged and older people are at risk of osteoporosis, and hip fractures related to low bone mass are a leading cause of nursing home entry for the elderly.
The NIA leads the Federal effort conducting and funding basic, clinical, social, and behavioral research aimed at maintaining independence and improving lives of older people and their families. For more information on NIA and aging in general, visit the NIA website at www.nia.nih.gov . The public may also call the NIA's toll free information number at 1-800-222-2225 or TTY at 1-800-222-4225 for free consumer fact sheets on osteoporosis and other health issues of older people.