Osteoporosis. The old-woman's disease, right?
Indeed osteoporosis -- the degenerative condition that weakens bones and makes them susceptible to fracture -- affects more than 20 million American women. It is eight times more common in women than in men and affects one in every four women over 50.
But there are misconceptions about osteoporosis, and perhaps the most misleading is that the time to be concerned about it is in old age. In fact, the most critical time for building bone mass is the teen-age years. And there is much that women can be aware of between that time and old age to prevent the disease from eventually affecting them.
"This is where the public today really has a problem," says Dr. Eugenia Pavlov, director of the Greater Baltimore Osteoporosis Center in Owings Mills. "Bones grow most rapidly between the ages of 9 and 17," she says, pointing out that calcium is the chief nutrient in building bones. Young women eschewing dairy products today in favor of soda are getting a head start on an old woman's illness, she says.
Everyone continues to build or "store" bone until about age 30 or 35, when they reach their peak in mass and strength, says Dr. Pavlov, an endocrinologist. At that point, as part of the natural aging process, old bone begins to break down faster than new bone is formed and gradually bone loses its density.
Osteoporosis occurs when bones become too thin and brittle, making them vulnerable to fracture -- commonly of the spine, wrist and hip.
There are few warning signs of osteoporosis. The first signs, besides an actual fractured bone, might be a chronic backache, loss of height or the familiar dowager's hump that afflicts many older women. But waiting until one sees those signs -- often in the fifth or sixth decade -- to take action means treatment may come too late, say physicians and researchers.
"Growing children and teen-agers need at least 800 to 1,000 milligrams of calcium a day," or the equivalent of four 8-ounce servings of milk, says Dr. Pavlov. "But studies have shown that the majority of American girls get less than 400 mg a day." The "fast food meal with a Coke isn't optimal for women, either," she says, adding that boys' diets don't seem to be as calcium-deficient as girls'.
Women -- even those who eat well as youngsters -- face another threat at menopause, when bone density goes through a rapid decline because of the absence of estrogen.
Most women lose 2 to 10 percent of bone a year immediately following menopause, and that accelerated loss can last as much as seven years, says Jean Scott, an epidemiologist and researcher at the University of Maryland Medical School. "People who lose [density] more quickly are going to be at a higher level of risk for fracture," she says.
Dr. Scott is an investigator in an ongoing study at the university tracking hip fractures in women over 65 to try to predict who is at highest risk. The five-city study is in its seventh year and 'N involves nearly 2,500 women in the Baltimore area. "What we're really interested in is where we should be putting our efforts in prevention," says Dr. Scott.
Researchers generally agree that without estrogen replacement for post-menopausal women, bone loss will continue, though at a lesser rate after the initial adjustment years are over. Just how well a woman will weather that rapid-loss period depends on a lot of factors, including how much bone she has stored to begin with, how rapidly her particular body loses it, her lifestyle and even heredity.
"The most likely candidate for osteoporosis is probably a thin, small-boned woman with fair skin," says Dr. Christine Schneyer, associate director of endocrinology at Sinai Hospital. "She smokes, she might drink, she gets very little exercise and she probably doesn't like milk."
Unfortunately, the composite covers a lot of women, says Dr. Schneyer, leading a study getting under way at Sinai on preventing spinal fractures in post-menopausal women.
"But the most important predictor of who will get osteoporosis is low bone density," she says, "which can only be determined by a bone density study."
Bone density studies have become more common in at-risk women as diagnostic equipment has been improved. Today, state-of-the-art bone densitometry is done in a half-dozen facilities in town.
The machine, which works much like a traditional X-ray, scans the hip and spine and can give an accurate measurement of bone mineral density in critical sections of bone. These are then used by the physician to evaluate whether a patient is within the normal range for her age and whether treatment is advisable.
Bone mineral density measurements are most critical at menopause, says Dr. Pavlov, because that's when bone goes through the most rapid change and when a woman may need help deciding whether to opt for estrogen replacement.