Osteoporosis Medications and Prevention

October 12, 2011
Andrew B. Dott, MD, MPH

Osteoporosis --meaning porous, fragile bones --is a disease in which there is exaggerated loss of quantity and quality of bone, causing an increase in the risk of fractures. It's normal for the bones of both women and men to get thinner and more fragile with age.

Osteoporosis --meaning porous, fragile bones --is a disease in which there is exaggerated loss of quantity and quality of bone, causing an increase in the risk of fractures. It's normal for the bones of both women and men to get thinner and more fragile with age. But when the bones become so fragile that they break easily and health is endangered, that's the disease osteoporosis. Like other body tissues, bones continuously renew and repair. Old bone is removed and replaced by new bone. Osteoporosis occurs when there is an imbalance in bone metabolism. Either too much old bone has been removed or not enough new bone has been formed --or both. As a result, the honeycomb structure of bones becomes so hollow and fragile from the loss of mineral that they may break with only slight trauma such as opening a window, and sometimes can occur with no trauma at all. While the exact causes of this imbalance are unknown, osteoporosis is generally preventable and treatable. Age is the most important risk factor. Certain physical or lifestyle factors --such as a low calcium diet, lack of exercise, and smoking --can contribute to bone weakness in both sexes.

All bones suffer from this disease. But the majority of fractures occur in the vertebrae (spine), hip, and wrist. Fortunately, of those who have spine fractures, only a small percentage will be troubled by them. Fracture of the hip can be of considerable concern, since this injury often leads to immobility and loss of independence. A woman's risk of having a hip fracture is equal to the risk of breast, uterine, and ovarian cancer combined. Approximately 30% of women having a hip fracture die within six months.

Certain women are at special risk for osteoporosis. Women typically have lighter frames than do men, so they have less bone mass to draw from. Women also lose bone more rapidly during the first five to ten years following menopause when their ovaries produce less estrogen --the hormone that appears to protect against bone loss. Every woman's body goes through bone loss, bone replacement, and more rapid bone loss after menopause. Not every women, however, will develop osteoporosis.

There are certain risk factors for osteoporosis. These include:

  • Age; most fractures occur after age 75.
  • Gender; women are at greater risk than men.
  • Race; white and Asian women are at special risk.
  • Heredity; if osteoporosis runs in the family.
  • Being small-boned and thin
  • Inadequate diet, especially not enough calcium and vitamin D.
  • Physical inactivity.
  • Use of cigarettes or alcohol.
  • Certain bone-robbing medications (such as steroids and anti-seizure drugs).
  • Prolonged immobilization.
  • Being past menopause; women experiencing early menopause (before age 40), whether occurring naturally or medically induced (through surgical removal of ovaries, or ovarian damage from drugs or x-rays), have a higher osteoporosis risk because they live a longer time without estrogen's protection.
  • Excessive exercise or extreme weight loss. Rate of bone loss is also increased by conditions that result in stopping menstrual periods before menopause

Osteoporosis is not easy to detect since most warning signs don't usually occur until the disease has become advanced. One clue is prolonged and severe pain in the middle part of the back. Other clues involve changes in the shape of the spine. But even without these warning signs, bones could still be getting thin. Therefore, often health care providers recommend that the density of the bones be measured; the gold standard today in bone density testing is dual energy x-ray absorptiometry (called DEXA for short). There are several new laboratory tests (Pyri-Links measure the rate of change in bone metabolism. These tests require an early morning urine specimen and may be used to monitor the effectiveness of therapy.

MEDICATIONS

Estrogen replacement therapy (ERT), used to prevent osteoporosis, has also been proven effective in treating the disease. The bisphosphonate family of drugs is another approach. Within this family, alendronate (Fosamax) is known to inhibit bone breakdown, increase spine and hip bone mass, and decrease spinal and hip fractures. Alendronate is best reserved for treatment when estrogen is not appropriate; it can also cause irritation of the stomach and esophagus. Another bisphosphonate, etidronate (along with calcium), is available for osteoporosis treatment in some countries (but not in the U.S.) as Didrocal; in the U.S., etidronate (without calcium) is FDA-approved only for Paget's disease and is sold under the brand name Didronel. Other options for osteoporosis treatment include calcitonin --available as injections (Calcimar, Miacalcin) --and a nasal spray (Miacalcin; not available in Canada). All drugs effective in treating osteoporosis need adequate calcium to work effectively. Not every drug is right for every woman. Each woman's decision to begin treatment must be made after a complete discussion with her health care provider of each drug's benefits and risks, as well as her own circumstances.

PREVENTION

The first step is to achieve the greatest possible bone mass during the peak bone mass years of age 20 to 30. Then, the risk factors that can be controlled must be reduced or eliminated. Adequate calcium intake is critical. Most adults should get 1,000 mg per day of total calcium intake --or 1,500 mg for postmenopausal women who do not have adequate estrogen levels. One portion of dairy food, such as a glass of skim milk or a cup of yogurt, has 300 mg of calcium. Adults should consume 4-5 portions of dairy foods a day. In you cannot tolerate dairy products, you might want to consider taking 1 large TUMS (500mg) as a replacement for 2 portions of dairy food. Adequate vitamin D is also important; certain foods, sunshine, and/or taking a one-a-day multivitamin can help reach the recommended 400 IU daily. Exercise also helps build strong bones. Smoking and drinking alcohol also interfere with bone health. And for women at risk for osteoporosis, avoiding falls takes on added importance. Women at high risk for developing the disease may also want to consider taking estrogen replacement therapy (ERT); if taken for many years, ERT can reduce the risk of spine, hip, and wrist fractures by 50% to 70%.

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Reprinted with the kind permission from Andrew Dott, MD, MPHand the Institute of Endocrinology and Reproductive Medicine