No bones about it: what you must know about osteoporosis.

It forces its victims to bow their backs, but it is not a dictator. It consumes the bones of its victims while they yet live, but it is not some new technovirus from a Michael Crichton novel.

It is silent.

It is insidious.

"It" is osteoporosis, a crippling disease characterized by low bone density, painful fractures, and loss of independence. Its victims risk breaking important bone systems, such as the hips, the ribs, the wrist, or the spine, because they are too weak to withstand the stress of day-to-day activity. For example, a woman might break a hip from simply sitting down too quickly.

Few fully recover, and according to the American Dietetic Association a frightening 12 to 20 percent of hip fracture victims die of complications within a year, making osteoporosis one of the top five causes of death among North American women. It is estimated that in the United States alone the cost to care for and rehabilitate women who suffer from this debilitating disease has reached more than $10 billion per year.

Because it affects half of all women over 70, osteoporosis is commonly thought of as an "old woman's disease." But according to the National Osteoporosis Foundation 2 million American men also have been diagnosed with it, and another 3 million are at risk. Indeed, male osteoporosis victims suffer one third of all hip fractures and are less likely than women to survive such a trauma. Despite these statistics osteoporosis in men remains underdiagnosed, underreported, and inadequately researched.

It is no respecter of persons. Anyone at any age can be affected, for in reality osteoporosis is a pediatric disorder with a geriatic outcome. There is no cure, but much can be done to postpone and even prevent the onset of this malady.

Since osteoporosis is a disease of the bones, it is important to understand that the skeleton is not a hard, unyielding structure, but a complex, living system. It is constantly remodeling itself as small amounts of bone break off and are absorbed, and new bone is formed to take its place.

Bone growth, both in length and density, is at its greatest during puberty. Then for the next 10 to 15 years the bones continue to add width and mass. The key to beating osteoporosis is to achieve peak bone density during the time of life when your body is building your skeleton. Experts agree the best time to start is during the teenage years. Think of it as a bank account. The earlier you start to save, the more bone mass will be in your account when you retire.

But even if you are past puberty, there is still a lot you can do to keep yourself out of the valley of dry bones. According to the National Osteoporosis Foundation, two factors have the greatest impact on bone growth and maturity exercise and adequate calcium intake.

Much can be done to postpone and even prevent the onset of osteoporosis

Studies by the National Institutes of Health show young women to be particularly calcium-deficient, noting that 80 percent of girls aged 11 to 18 consume less than the U.S. recommended daily allowance of calcium. Indeed, most American women get less than half of the 1,000 to 1,500 milligrams recommended by the National Center for Nutrition and Dietetics. Combine that with today's more sedentary lifestyle, and this generation is an epidemic waiting to happen.

Of course, the richest and most convenient source of calcium is milk, and therein lies the rub. Many weight-conscious young women refuse to drink milk because of its high fat content. The good news is that even low-fat and nonfat dairy products contain the same amount of calcium as their more full-figured counterparts.

Other excellent sources of calcium are dark-green vegetables (such as broccoli, turnip greens, and cabbage), sunflower and sesame seeds; and almonds. Although calcium from food sources should be your first choice, you can make up any shortfall with a supplement. There are, however, significant differences in the types of calcium supplements that are available. Calcium from malates, citrates, and glutamates is all well absorbed, while calcium carbonate and calcium found in antacids are less easily absorbed. Ask your doctor or pharmacist to recommend a supplement that is right for you.

Exercise is also vital to bone strength, a fact vividly demonstrated by early space missions. Astronauts, who were in top physical condition but who had spent days in weightlessness, experienced loss of bone strength on their return to earth. NASA responded by installing exercise devices on subsequent spacecraft to provide astronauts with a resistance workout, and the problem disappeared.

The principle behind the value of exercise is that bones respond to muscle action, making them stronger. The National Osteoporosis Foundation recommends a regular regimen of weight-bearing exercise in which bone and muscles work against gravity. So hit the beach! Ride a bike! Smack a handball, or join the church volleyball team! Exercise doesn't have to be elaborate to be effective, but it does have to be consistent. Remember, the benefits last only as long as the program is maintained.

The biggest cause of bone thinning in women is menopause. According to the National Osteoporosis Foundation, women can lose up to 20 percent of their bone mass in the five to seven years following menopause because of the loss of the hormone estrogen. But there are other important factors that may contribute to your risk of osteoporosis, regardless of your age, including:

* A family history of osteoporosis

* Caucasian or Asian descent

* Small or thin frame

* Early menopause

* Surgical removal of ovaries

* Smoking and excessive alcohol consumption

* Fair skin

* Use of certain medications, including thyroid medication or steroids

* A diet high in caffeine and low in calcium

* A sedentary lifestyle

* Women who have never been pregnant

The more items that apply to you, the greater your risk of developing osteoporosis. According to a spokesperson for the Arthritis and Osteoporosis Care Center at Nashville's Baptist Hospital, this disease is exceptionally dangerous because in its early stages there are often no symptoms. It does not manifest itself until something breaks. But an early warning sign may be the loss of height. This happens when the vertebrae begin to weaken and collapse. As these fractures mount up, a curving of the spine, commonly called dowager's hump, may occur. If you notice a loss of height or change in posture, or experience sudden, unexplained pain in the hips, lower back, or legs, you should tell your doctor. "In fact," the spokesperson said, "all women past menopause, and anyone over 30 with a family history of osteoporosis, should consult their doctor to evaluate their risk of the disease."

Medical science is rapidly developing accurate and effective methods to diagnose and treat osteoporosis. Bone mineral density tests--far superior to simple X-rays--can detect the disease before a fracture occurs, predict your chances of fracturing in the future, and determine your rate of bone loss if the test is conducted at intervals of one year or more.

As the old adage goes, an ounce of prevention is worth a pound of cure. And while there may be nothing you can do about your family medical history, you can impact your lifestyle. It has been estimated that half of all osteoporosis fractures could be eliminated just by getting the proper amount of calcium. And a regular regimen of exercise not only pays dividends for your bones, but works wonders for your heart and lungs. It's never too early or too late to start taking care of yourself.

RELATED ARTICLE: For More Information

National Osteoporosis Foundation 1150 17th St., NW Washington, D.C. 20036-4603 [phone]

National Institute of Health NIA Information Center P.O. Box 8057 Gaithersburg, MD 20898-8057 [phone]

American Dietetic Association 216 West Jackson Blvd. Chicago, IL 60606

National Center for Nutrition and Dietetics Consumer Nutrition Hotline [phone]

RELATED ARTICLE: Counting Up Your Calcium

Food                                   Calcium (mg./serving)

Yogurt, plain, nonfat (8 oz.)                           452
Yogurt, plain, low-fat (8 oz.)                          415
Ricotta cheese, part skim (1/2 cup)                     337
Skim milk (1 cup)                                       302
1 percent milk (1 cup)                                  300
2 percent milk (1 cup)                                  296
Whole milk (1 cup)                                      291
Buttermilk (1 cup)                                      285
Tofu, raw, firm (1/2 cup)                               258
Cheddar cheese (1 oz.)                                  204
Turnip greens (1 cup)                                   197
Mozzarella cheese, part skim (1 oz.)                    183
Beet greens (1 cup cooked)                              164
Chinese cabbage (pak choi) (1 cup cooked)               158
Tempeh (1 cup)                                          154
Kale (1 cup cooked)                                      93
Dried figs (3 figs)                                      82
Garbanzos (1 cup)                                        80
Cottage cheese, 1 percent fat (4 oz.)                    69
Parmesan cheese (1 tablespoon)                           62
Orange (1 medium)                                        52
Okra (1/2 cup cooked)                                    50
Black beans (1 cup)                                      46
Tortilla, corn (1 tortilla)                              45
Broccoli (1/2 cup chopped cooked)                        35
Orange juice (1 cup)                                     24

Source: United States Department of Agriculture, Nutrient Database for Standard Reference, Release 11