The researchers don't dismiss the vitamin pills. They don't know if the results would be similar for women of other ethnic groups, elderly women, or those more severely lacking vitamin D.
The researchers included John Aloia, MD, of the Bone Mineral Research Center at Winthrop University Hospital in Mineola, N.Y. The study appears in the Archives of Internal Medicine.
Strong bones are important throughout life. Bone density peaks at about age 30. According to the National Osteoporosis Foundation, the critical years for building bone mass are from prior to adolescence to about age 30.
Bones naturally thin as we age. The worst cases result in osteoporosis -- thin, brittle bones that are more likely to break. Both men and women can develop osteoporosis or osteopenia, a milder condition that can lead to osteoporosis. Certain people are more likely to develop osteoporosis, and vitamin D deficiency makes it more likely.
Getting Vitamin D
Vitamin D is involved in bone health, along with calcium and other minerals. The body can make vitamin D when exposed to sunshine. It can also get vitamin D from supplements or certain foods, such as low-fat dairy products.
In old age, black women tend to get fewer bone fractures than whites.
It's harder for blacks to make vitamin D. Their skin color provides some natural sun protection, filtering out some sunshine needed to produce vitamin D.
Keeping Bones Strong
Factors that raise the odds of osteoporosis include:
- A family history of osteoporosis
- Personal history of fracture after age 50
- Current Smoking
- Excessive alcohol use
- Getting little or no weight-bearing exercise
- Being small-framed or thin
- A diet low in bone-friendly foods -- low lifetime calcium intake
- Certain medications -- such as steroids and seizure medications
Steps to keep bones strong include:
Some patients may also benefit from medications to prevent or treat osteoporosis. A bone density scan can check bone health.
Aloia's study included 208 healthy postmenopausal black women aged 50-75 who had gone through menopause.
The women were moderately active. None were taking hormone therapy. Only 7% were smokers. Their average BMI (body mass index) was borderline obese.
The women were randomly given pills containing 800 international units (IU) of vitamin D or placebos with no vitamin D. No one knew which pill they were taking.
Everyone also got calcium supplements to make sure they consumed 1,200 to 1,500 milligrams of calcium per day.
The researchers increased vitamin D supplements to 2,000 IU in the study's last year.
Checking Bone Density
The women got bone scans every six months throughout the study. At the study's start, most women (65%) had normal bone density. About 34% had lower-than-normal bone density measures (osteopenia). Only 1.4% had osteoporosis.
No bone benefits were seen in the women taking vitamin D, write the researchers. They note that nearly nine out of 10 women in the vitamin D group took the pills as directed.
It's the first study of vitamin D in postmenopausal black women, write Aloia and colleagues. The findings "lend support to re-examination of optimal vitamin D nutrition for skeletal health in postmenopausal women of other ethnic groups," they write.