The risk of developing osteoporosis increases in both women and men as they grow older. Women are more susceptible than men, because compared with men they have less total bone mass to begin with and because estrogen plays a vital role in bone health. As the production of natural estrogen drops off during menopause, the rate of bone loss begins to pull ahead of the rate of bone formation.
In addition to age and gender, other risk factors include:
- a history of fracture as an adult (especially after age 40)
- a history of fracture in a first-degree relative (male or female)
- ethnicity (white and Asian women are at greater risk than women in other ethnic groups).
Risk factors that can be changed include:
- low body weight (under 127 lbs for women)
- low estrogen levels in women; low testosterone levels in men
- prolonged low calcium and vitamin D intake
- eating disorders
- lack of exercise (or excessive exercise that leads to missed menstrual periods during a woman’s premenopausal years)
- ongoing use of certain drugs, such as corticosteroids like prednisone, or some medications used to treat prostate or breast cancer
- excessive alcohol consumption.
One of the primary determinants of osteoporosis risk is family history. The genes that are important in determining susceptibility to osteoporosis have not been fully identified, but they may account for as much of 70 to 80% of osteoporosis risk.
Osteoporosis also can be caused by other diseases or certain medications. This is called secondary osteoporosis. For instance, many people with severe asthma, rheumatoid arthritis, inflammatory bowel disease, or multiple sclerosis take corticosteroids, which are a common cause of osteoporosis. Other drugs that can cause osteoporosis include anticonvulsants, which are used to treat epilepsy, and inappropriately high doses of thyroid hormone replacement. Recently, a class of drugs used to treat diabetes, thiazolidinediones, was found to be associated with an increased risk of fracture.
A number of other hormonal disorders, including an overactive thyroid gland (hyperthyroidism), Cushing’s syndrome (excessive steroids produced by the body), and an overactive parathyroid gland (hyperparathyroidism), can cause bone loss in men and women. Inflammatory diseases, such as inflammatory bowel disease (Crohn’s disease and ulcerative colitis), lupus, and rheumatoid arthritis, also can contribute to bone loss, as can malabsorption syndromes such as celiac disease.
When a man develops osteoporosis, a thorough medical evaluation should be performed to determine the underlying cause. Osteoporosis in a premenopausal woman or in any woman who is not responding to treatment also warrants evaluation for secondary causes of the disease.