April 27, 2010
Osteoporosis in women — and men?
Most people think of osteoporosis — a condition characterized by a loss of bone mass and density — as mainly a health problem for older women. If you’re male, you may have breathed a small sigh of relief — or simply tuned out — whenever osteoporosis came up. It wasn’t a disease you needed to worry about.
True, osteoporosis is more common in women. But men are by no means immune.
Consider these facts:
- Two million American males have the condition, and millions more have osteopenia, a lesser degree of bone loss.
- By 2020, the number of men in the United States with thinning bones is expected to top 20 million. Death rates from heart disease and other traditional killers of men are declining, so more men are living long enough to contend with age-related conditions like osteoporosis.
- Osteoporosis starts earlier and gets worse faster in women because of midlife hormonal shifts, but starting at about age 65, both sexes lose bone at about the same rate.
A particularly dire consequence of osteoporosis is a broken bone. One in four men over age 50 can expect to have an osteoporosis-related fracture some time in his life. That’s better than the odds women that age face. But regardless of gender, a broken bone in middle or old age can exact a high price: lingering pain, loss of mobility, long-term disability, and loss of independence.
Caused by low testosterone
Osteoporosis is associated with some male-only conditions — for example, abnormally low testosterone levels (hypogonadism). Both women and men can get the skin condition psoriasis, but research suggests it is linked to loss of bone density in men. Androgen deprivation therapy, which is one way to treat advanced prostate cancer, usually involves drugs that interfere with testosterone. But testosterone promotes bone formation, so those drugs can wind up weakening bones.
Some medications affect bones in both sexes. Long-term cortisone treatment for conditions such as asthma or rheumatoid arthritis can diminish bone mass. The proton-pump inhibitors (Nexium, Prevacid, others) used to treat gastroesophageal reflux disease (GERD) and the selective serotonin reuptake inhibitor antidepressants (Paxil, Prozac, others) have come under scrutiny after the publication of studies suggesting that they, too, may contribute to bone loss. Experts warn that it’s too early to draw firm conclusions about the danger to bone health from these drugs. Still, talk with your doctor if you’re taking these medications.
Bone health advice: the same for all?
Lifestyle and health habits also are a major factor in osteoporotic risk, for both men and women. Smoking and heavy alcoholic drinking weaken bones. Interestingly, men are more likely than women to engage in those behaviors.
Keeping bones strong is yet another reason to exercise. Vitamin D is also important for bone health — as well as overall good health. Many experts now say we should be getting at least 800 to 1,000 international units (IU) of vitamin D daily, especially during the winter months in the northern latitudes when limited sunlight reduces the amount of the vitamin produced naturally by the skin.
But when it comes to perhaps the most familiar prevention tip — keep your calcium intake high — the recommendations for men are cloudier. Many studies point to an association between long-term daily calcium intake at levels of 1,500 mg or more and a greater risk of developing advanced prostate cancer — although it’s important to note that not all have. On the other hand, there’s no question that some calcium is needed to maintain bone strength, and there’s a string of results that suggest the mineral may lower colon cancer risk. Researchers also note that the calcium–prostate cancer connection may stem from low vitamin D intake.
Great Britain set its daily calcium recommendation at 700 milligrams (mg), which may be closer to the amount that most men should be consuming. For men in danger of developing osteoporosis, the right balance may be about 700 mg to 1,000 mg of calcium a day, which can be achieved with a normal diet that includes one to two servings of dairy products, and plenty of vitamin D, which usually means taking the vitamin in pill form.
Benefiting from women’s experience
Men are fortunate because women have pioneered osteoporosis diagnosis and treatment. Men may, however, have fewer treatment choices at this time because some drugs have been tested only in women. Alendronate (Fosamax), the oldest and best-studied drug in the bisphosphonate class, has been shown to be effective in men. An alternative for men receiving androgen deprivation therapy is one of the selective estrogen receptor modulator drugs. These medications, originally developed to treat breast cancer, help preserve bone by mimicking the action of estrogen. And clinical trials show that an experimental drug, denosumab, may have promise for treating men with bone loss resulting from hormonal therapy.
How much Vitamin D should a woman take?
Q. On the basis of a blood test, my doctor wants me to take high doses of vitamin D for three months. I hear there are wide variations among laboratories performing these tests. Should I trust my first results, or take the test again? What are the risks of taking high doses of vitamin D?
A. Vitamin D is essential to bone metabolism; below-normal blood levels can increase your risk for osteoporosis, falls, and possibly fractures. There are three main forms of vitamin D. The active form found in our bodies is 1,25-dihydroxyvitamin D; the body makes it from two precursors, vitamin D2 and vitamin D3. Foods and supplements are the main sources of vitamin D2. Vitamin D3 is produced in the skin through exposure to ultraviolet light (as in sunlight); it’s also found in foods and supplements. Both vitamin D2 and vitamin D3 are converted into active vitamin D in the liver and the kidneys.
Vitamin D levels decline when sun exposure is reduced, especially during the winter in northern latitudes. In addition, we absorb vitamin D less efficiently with age. So older people and those with limited sun exposure (including those who are housebound) are especially at risk for low blood levels of vitamin D. Other risk factors are malabsorption syndromes (like Crohn’s disease), dark skin (which blocks vitamin D production through sunlight), and excess fat, which can hinder the release of vitamin D into the blood. Too little vitamin D in the blood triggers the release of parathyroid hormone (PTH), stimulating bone resorption (breakdown). When blood levels of vitamin D rise above 30 nanograms per milliliter (ng/mL), PTH returns to normal and bone resorption slows. Most experts believe that a vitamin D level below 30 ng/mL can cause excessive bone resorption.
For most women, getting 800 to 1,000 international units (IU) of vitamin D per day provides enough vitamin D for normal bone metabolism. If a vitamin D level is below 30 ng/mL, the deficiency can be corrected by taking high doses — 50,000 IU of vitamin D as a single dose once a week for six to eight weeks.
The safe upper limit for vitamin D supplementation is 2,000 IU per day. But over limited time periods, even very high doses are safe. The chief adverse effects, which are due to high levels of calcium in the blood and urine, do not occur unless vitamin D levels reach 88 ng/mL — a concentration that is unlikely to result from either high-dose treatment or regular supplementation.
It’s true that laboratory test results can vary considerably. Still, if your blood level is hovering around 30 ng/mL, you could take the high doses for six to eight weeks. It’s safe — and less expensive than being tested a second time. After you’ve completed the high-dose treatment, take a daily vitamin D supplement of 800 to 1,000 IU. And be sure to get 1,200 to 1,500 milligrams of calcium a day through diet or supplements.
— Celeste Robb-Nicholson, M.D.
Editor in Chief, Harvard Women’s Health Watch