Vitamin D, calcium supplements may not lower fracture risk
NEW YORK: Older adults who take vitamin D and calcium are no less likely to break their hips or other bones than peers who don’t use these supplements, a research review suggests.
Researchers examined data from 33 previous trials with a total of more than 51,000 people aged 50 or older who were living in the community, not in nursing homes or other institutional settings. They found no difference in fracture risk among people who got no treatment, a placebo or dummy pill, or vitamin D and calcium alone or in combination.
“It is time to stop taking calcium and vitamin D supplements for the community-dwelling older adults,” said lead study author Dr. Jia-Guo Zhao, a researcher in the department of orthopedic surgery at Tianjin Hospital in China.
Vitamin D helps the body use calcium to support bone health, and many older adults are advised to take one or both of these supplements. The recommended daily intake of vitamin D for most adults is 600 IU (international units), or 800 IU after age 70.
“The guidelines should be changed,” Zhao said by email. “We think that improving the lifestyle, getting enough exercise and enough sunshine, and adjusting the diet may be more important than taking these supplements.”
Some people can get enough vitamin D from spending time outside, and older adults can also lower their risk of falls and fractures by doing things like maintaining a healthy weight or doing exercises designed to improve balance and coordination.
When people take daily vitamin D doses of 1,000 IU or higher, however, they run the risk of serious side effects, particularly when used in combination with calcium. Some previous research has linked high doses of vitamin D to an increased risk of falls, fractures, kidney stones, certain cancers and premature death.
For the current study, researchers examined data only from clinical trials that randomly assigned some people to take vitamin D or calcium, alone or in combination, and some individuals to receive a placebo or no treatment at all.
All of the trials looked at the risk of hip fractures, spinal fractures or other types of broken bones.
The lack of associations between calcium, vitamin D and fracture risk was seen in both men and women, regardless of supplement dose or any previous history of fractures, researchers report in JAMA.
One limitation of the study is that some of the trials in the analysis didn’t include pre-treatment measurements of vitamin D blood levels, which might have influenced how much the supplements impacted fracture risk. Some of the trials also were not high quality experiments, the authors note.
Even though severe calcium or vitamin D deficiencies can contribute to loss of bone density and an increased risk of fractures, people with this problem are typically too sick to be included in clinical trials, noted Dr. Kurt Kennel, a specialist in endocrinology, metabolism and nutrition at the Mayo Clinic in Rochester, Minnesota.
“A key message which is not new but reinforced by this study is that menopausal women and older men with osteoporosis should not equate calcium and/or vitamin D supplementation with adequate treatment to reduce the risk of osteoporotic fractures,” Kennel, who wasn’t involved in the study, said by email.
Osteoporosis, or a loss of bone density, occurs naturally with age and can also be accelerated when women go through menopause.
When people do need more vitamin D or calcium, they should look at their diet first, Kennel advised.
“Pretty much every guideline states that dietary calcium is the initial approach to obtaining adequate calcium, thus in that regard no changes to guidelines are needed,” Kennel said.
But people who already take supplements shouldn’t stop without speaking to a doctor.
“Routine initiation of calcium and/or vitamin D supplementation in older women and men for prevention of fracture should not be advised,” Kennel added.