Men and women age differently, no doubt about it. One of the primary differences is in bone health. Half of all women will suffer a fracture due to osteoporosis, a condition characterized by a severe reduction in the density and strength of bones. If you go to any pharmacy or leaf through any consumer magazine, you'll see promotions for products to combat the condition. The ads all feature sparkling, active older women who obviously are taking whatever advice is being recommended.

What the ad campaigns don't tell you is that men can develop osteoporosis too. It occurs less frequently in men, primarily because men and women produce different levels of hormones. Both sexes begin to lose bone mass at about 0.3 to 0.5 percent per year after about age 40 to 50. Women, however, experience a higher rate of bone loss during menopause. The net result is an average bone loss of 40 to 50 percent in women, and 20 to 30 percent in men. But the lower rate that men experience is still significant. Men who have low bone mass to begin with, or who are at the upper end of bone loss, are at highest risk for osteoporosis.

The effects of osteoporosis are the same in men and women. One early sign is a backache. Later, as bones in the spine begin to crumble, people with osteoporosis may lose height and develop a hump in their back. Usually there are no symptoms until a person breaks a weak bone after falling or simply rolling the wrong way in bed. Common fracture sites in men include the upper thigh (commonly referred to as a hip fracture) and vertebrae in the lower back. Suffering a hip fracture more than triples a man's risk of dying within the year. A fracture of a vertebra more than doubles the risk. Vertebral fractures are not as obvious as other fractures; often the only symptom is a nagging backache.

Men can begin their journey to better bone health by working on their diet. Calcium is the main mineral component of bones, so be sure to get plenty of calcium every day. The National Institutes of Health reports that men up to age 65 should get a total of 1,000 mg of calcium per day from all sources, including diet and supplements. Men over 65 need 1,500 mg of calcium per day.

Dairy products, such as milk and cheese, contain large amounts of calcium, but if you don't like dairy (or if dairy doesn't like you), there are alternate sources. Leafy greens, like spinach and kale, and legumes, like navy beans and kidney beans, can be an important part of your diet. If you have trouble getting enough calcium from your food, a daily supplement will bring you up to the recommended amount.

Vitamin D, which helps your body absorb calcium, is also essential to bone health. Vitamin D is fat soluble, so your body can store it. Between 400 and 600 IU daily is recommended. A good source of vitamin D is a walk in the sun every day -- 15 minutes with your arms and face exposed is enough. If you can't do that (or if you live in a northern latitude, such as Boston, where the sun is too low during the winter), then you should take a daily vitamin D supplement along with your calcium. Remember that most milk is fortified with vitamin D.

Exercise, especially activity that puts stress on your bones, also helps maintain bone health. Besides walking, weight lifting is another excellent form of exercise; just be sure you are sensible about the amount and frequency.

Men need to concentrate on their lifestyle to maintain their bone health, because none of the FDA-approved medications for postmenopausal women have been similarly approved for men. If your doctor suggests that you try one of the newer medications, such as Fosamax (alendronate), be aware that the beneficial effects in men are uncertain, as are the side effects.

Risk Factors for Osteoporosis

Things you can change:

Things you can't change: