As men live longer, they're having to cope with a condition that used to be thought of as a women's disease.

Osteoporosis, a condition characterized by a loss of bone mass and density, has been viewed mainly as a health problem for older women. If you're a member of the male sex, 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.

Unfortunately, gentlemen, it's not quite that simple.

True, osteoporosis is more common in women. But men are by no means immune. 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.

Caused by low testosterone

Osteoporosis is associated with some male-only conditions — for example, abnormally low testosterone levels (hypogonadism). Psoriasis isn't exclusively a male disease, but research suggests the skin condition is linked to loss of bone density in men but not in women. One strategy for controlling advanced prostate cancer is androgen deprivation therapy, which typically involves taking 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, you may want to confer with your doctor if you're taking these medications.

Lifestyle and health habits also are a major factor in osteoporotic risk, for both men and women. Smoking and heavy alcoholic drinking weaken bones, and men are more likely than women to engage in those behaviors.

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, which is still better than the odds women that age face. For women, there's a one-in-every-two chance of fracture. Regardless of gender, a broken bone in middle or old age can exact a high price: lingering pain, loss of mobility, long-term disability, loss of independence.

Bone health advice: the same for all?

When it comes to preventing osteoporosis, much of the advice applies to both men and women. 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.