Fighting Osteoporosis

By Joseph M. Lane, M.D. and Judith Andariese, R.N.

The huge bone factory we know as the human skeleton serves many wonderful and incredible functions. There's always something going on there, since bone is living tissue, constantly remodeling itself.

Some cells remove old bone (resorption), while others build new bone (formation). As we get older, bone loss outpaces bone formation. Some people lose bone mass more rapidly than others, for reasons that scientists don't yet fully understood.

Osteoporosis results when this decrease in bone mineral density is significant. It's a disease of global proportions, affecting more than 200 million people worldwide—over 20 million women and 5 million men in the United States alone.

Who's at Risk?
Osteoporosis—which literally means "porous bones"—has been called the "silent" disease, because the loss of bone tissue progresses gradually (often without pain or symptoms) before a fracture occurs.

But fractures do occur—a million and a half each year, usually of the spine, hip or wrist. White and Asian women have twice as many fractures as African-American women. Hispanic women are also at significant risk.

Having risk factors doesn't mean you will develop the disease or have a fracture. ButÉif you have a number of the following characteristics, you should discuss testing your bone mineral levels with your doctor.

Major Risk Factors

  • Smoking
  • Low body weight (less than 127 lbs.)
  • Corticosteroid medications/Chemotherapy
  • Personal or family history of low-trauma fractures

    Other Risk Factors

  • Being female
  • Early menopause
  • Inadequate calcium intake
  • Family history of osteoporosis
  • Absence of menses (except for pregnancy)
  • Excessive alcohol consumption

    Your "Bone Bank"
    They call it "a pediatric disease with geriatric consequences," because the groundwork for healthy bones—or for eventual osteoporosis—is laid in childhood. The best prevention strategy is to start acquiring peak bone mineral levels early. Vigorous exercise and adequate intake of calcium are most important.

    Think of bone as a bank account, where you are "making deposits" and "withdrawals." In childhood, bone is being added faster than it's being removed. As a result, bones become larger, heavier and denser. In adolescence and early adulthood (11-24 years), bone formation occurs rapidly until peak bone mass is reached. After 35, "withdrawals" slowly begin to exceed "deposits."

    Remember: the stronger your "bank account," the longer it takes to draw it down. For women, "withdrawals" become much more frequent after menopause. By age 65, loss rate slows down and both women and men seem to lose bone mass at the same rate.

    Healthy Measures
    Midlife presents an ongoing opportunity to maintain healthy bones. In later life, those with osteoporosis can take measures to prevent further bone loss and fractures, including optimal daily consumption of calcium and vitamin D, plus frequent weight-bearing exercise. For post-menopausal women, especially those at high risk, estrogen replacement and non-hormonal therapies may be important.

    Calcium and vitamin D are the key ingredients for preventing excessive bone loss and maintaining healthy bones. They should be taken throughout life. Vitamin D, essential for the absorption of calcium, can be obtained in most multivitamin preparations, since it is not readily available from dietary sources other than milk or food products fortified with vitamin D. Sunshine, of course, is the primary source of vitamin D.

    The following recommended daily allowances for calcium intake can be achieved through dietary and/or supplemental sources.

    Treatment Strategies
    Once bone loss has been established, your doctor may recommend a medical treatment to reduce both the rate of loss and the risk of fractures.

  • Bisphosphonate drugs, such as alendronate and residronate, will increase bone density and reduce the risk of some fractures significantly. Alendronate has also been approved for use by men.
  • Estrogen Replacement Therapy (ERT or HRT) is approved for the prevention of osteoporosis. Selective Estrogen Receptor Modulators (SERMs) such as raloxifene also increase bone density and reduce the risk of some fractures. Raloxifene may also offer protection against breast cancer.
  • Calcitonin is a nasal spray formulation that modestly reduces bone turnover and appears to decrease the incidence of spinal fractures. It is purported to have some analgesic effects for acute spinal fractures.
  • On the horizon: PTH (parathyroid hormone), an injectable treatment that will enhance bone formation.

    It should be approved for use in late 2001.

    Bone loss is an inevitable part of living a long life. And as life expectancies become more extended, attention needs to be paid to the quality of that life. The tools for preventing, measuring and treating osteoporosis are there. We can all take steps at many points in our lives to promote good bone health. It's never too late!

    Dr. Lane is chief of the Metabolic Bone Disease Service, medical director of the Osteoporosis Prevention Center and director of the Clinical Research Center at Hospital For Special Surgery in NYC. Ms. Andariese is the director of the Osteoporosis Center at Hospital For Special Surgery.