WEDNESDAY, June 26 (HealthDay News) -- Although there has been
significant debate about whether calcium and vitamin D supplements
are beneficial for older women, new research suggests that the
answer may be yes for those who are taking hormone replacement
Women using HRT who also took daily supplements of calcium and
vitamin D saw a 40 percent reduction in their rate of hip fractures
compared to women who took placebo supplements, according to the
"We found that women who were on hormones had less hip
fractures, and women who were on hormones and calcium and vitamin D
supplements had even fewer hip fractures," said study author Dr.
John Robbins, a professor of medicine at the University of
California at Davis.
Results of the study were published online June 26 in the
As many as half of all women over 50 will have an
osteoporosis-related fracture in their lifetime, according to the
U.S. Preventive Services Task Force (USPSTF). Osteoporosis is a
condition caused by a loss of bone mass and density, which leaves
bones fragile and more susceptible to fractures. Calcium is an
important component in bone growth, and vitamin D helps the body
What's not clear is if supplements of these nutrients are as
helpful in keeping bones strong as they are from natural sources,
such as diet. The USPSTF recently looked at the effect of 1,000
milligrams of daily calcium and 400 international units of vitamin
D. In February, they concluded that women shouldn't take calcium
and vitamin D supplements because the available evidence wasn't
strong enough to show a significant benefit. They added that the
benefits of higher doses are unknown.
The new study included data from the Women's Health Study on
about 30,000 postmenopausal women between the ages of 50 and 79.
Many of the women were taking hormone replacement therapy -- either
estrogen alone or a combination of estrogen and progesterone.
Just over 16,000 women participated in the calcium and vitamin D
portion of the study. They were randomly selected to receive either
a placebo or 1,000 milligrams of calcium and 400 international
units of vitamin D each day. The average follow-up time was about
The hormone therapy and the supplements together were the most
effective treatment for reducing hip fracture risk. The researchers
found that the combination reduced the risk of hip fracture by 57
Overall, the rate of hip fracture was 11 per 10,000 women per
year for those who took both hormones and supplements. Women who
took only hormones had a hip fracture rate of 18 per 10,000, while
those who took only supplements had a hip fracture rate of 25 per
10,000. Women who received neither therapy had 22 hip fractures per
The researchers weren't able to tease out whether vitamin D or
calcium had any benefits on their own. All of the women who took
one supplement also took the other.
The study also was unable to find an optimal dose to help
prevent hip fracture, although it appeared that women with a
calcium intake of 1,200 milligrams and higher (from diet and
supplements) might garner more benefit, Robbins said. The
researchers saw a similar trend in lower hip fracture rates for
women with higher vitamin D intake.
"In moderation, I think there's relatively little risk of harm
from calcium or vitamin D," Robbins said.
"If a woman is taking hormones and other bone-enhancing drugs,
she should also take calcium and vitamin D supplements in
moderation or get them from dietary sources," he said.
Dr. Jill Rabin, chief of ambulatory care, obstetrics and
gynecology at Long Island Jewish Medical Center in New Hyde Park,
N.Y., agreed that there doesn't appear to be a significant downside
to taking these supplements if a woman doesn't have side effects,
such as constipation, from taking them.
"We can get a lot of calcium from our diet, and that's probably
the best way to get it," Rabin said. "But if you can take a
supplement without ill effects, you can certainly continue. And
women considering taking hormone therapy might also want to add
But, she added, the question of whether vitamin D and calcium
can provide a significant reduction in fracture risk in women still
needs more study. "The question hasn't been answered yet," she
As for hormone therapy, which is often prescribed for symptoms
of menopause, doctors recommend the lowest possible dose for a
short period of time. Use of hormone therapy has been linked to a
variety of health problems, including risk of breast cancer, stroke
and blood clots, according to the USPSTF.
Learn more about calcium and where to find it in your diet from
U.S. National Institutes of Health Office of Dietary