This article was published by the National Institutes of Health Osteoporosis and Related Bone Diseases~National Resource Center
2 AMS Circle, Bethesda MD 20892-3676
Osteoporosis, a disease that causes the skeleton to weaken and bones to break, is a significant threat to more than two million men in the United States today. Experts estimate that one-fifth to one-third of all hip fractures occur in men and that symptomatic vertebral (spine) fractures occur about half as often in men as in women. After age 50, six percent of all men will suffer a hip fracture as a result of osteoporosis. In 1994, osteoporotic fractures in men accounted for annual costs of $2.7 billion, or one-fifth of the total cost of osteoporotic fractures in the U.S.
Despite these compelling figures, a majority of American men view osteoporosis solely as a "woman's disease," according to a 1996 Gallup Poll. Moreover, among men whose lifestyle habits put them at increased risk, few recognize the disease as a significant threat to their mobility and independence.
Osteoporosis develops less often in men than in women because men have larger skeletons, bone loss starts later and progresses more slowly, and there is no period of rapid hormonal change and accompanying rapid bone loss. However, in the last few years the problem of osteoporosis in men has been recognized as an important public health issue, particularly in light of estimates that the number of men above the age of 70 will double between 1993 and 2050.
Clearly, more information is needed about the causes and treatment of osteoporosis in men, and researchers are beginning to turn their attention to this long-neglected group. For example, in 1999, the National Institutes of Health launched a major research effort that will attempt to answer some of the many questions that remain. The seven-year, multi-site study will follow more than 5,000 men ages 65 and older to determine how much the risk of fracture in men is related to bone mass and structure, biochemistry, lifestyle, tendency to fall, and other factors.
The results of such studies will help physicians better understand how to prevent, manage and treat osteoporosis in men. But much is already known. This fact sheet answers some of the fundamental questions.
What Causes Osteoporosis?
Bone is constantly changing - that is, old bone is removed and replaced by new bone. During childhood, more bone is produced than removed, so the skeleton grows in both size and strength. The amount of tissue or bone mass in the skeleton reaches its maximum amount by the late twenties. By this age, men typically have accumulated more bone mass than women. After this point, the amount of bone in the skeleton typically begins to decline slowly as removal of old bone exceeds formation of new bone.
In their fifties, men do not experience the rapid loss of bone mass that women have in the years following menopause. By age 65 or 70, however, men and women lose bone mass at the same rate, and the absorption of calcium, an essential nutrient for bone health throughout life, decreases in both sexes.
Once bone is lost, it cannot be replaced. Excessive bone loss causes bone to become fragile and more likely to fracture. This condition, known as osteoporosis, is called a "silent disease" because it progresses without symptoms until a fracture occurs.
Fractures resulting from osteoporosis most commonly occur in the hip, spine, and wrist and can be permanently disabling. Hip fractures are especially likely to be disabling. Perhaps because such fractures tend to occur at older ages in men than in women, men who sustain hip fractures are more likely to die from complications than are women. More than half of all men who suffer a hip fracture are discharged to a nursing home, and 79 percent of those who survive for one year after a hip fracture still live in nursing homes or intermediate care facilities.
Primary and Secondary Osteoporosis
There are two main types of osteoporosis: primary and secondary. In cases of primary osteoporosis, the condition is either caused by age-related bone loss (sometimes called senile osteoporosis) or the cause is unknown (idiopathic osteoporosis). The term idiopathic osteoporosis is used only for men less than 70 years old; in older men, age-related bone loss is assumed to be the cause.
At least half of men with osteoporosis have at least one (sometimes more than one) secondary cause. In cases of secondary osteoporosis, the loss of bone mass is caused by certain lifestyle behaviors, diseases or medications. The most common causes of secondary osteoporosis in men include exposure to glucocorticoid medication, hypogonadism (low levels of testosterone), alcohol abuse, smoking, gastrointestinal disease, hypercalciuria and immobilization.
Causes of Secondary Osteoporosis in Men
- Glucocorticoid excess
- Other immunosuppressive drugs
- Alcohol excess
- Chronic obstructive pulmonary disease and asthma
- Cystic fibrosis
- Gastrointestinal disease
- Anticonvulsant medications
- Osteogenesis imperfecta
- Neoplastic disease
- Ankylosing spondylitis and rheumatoid arthritis
- Systemic mastocytosis
Glucocorticoids are steroid medications used to treat diseases such as asthma and rheumatoid arthritis. Bone loss is a very common side effect of these medications. In fact, exposure to glucocorticoids accounts for 16-18 percent of osteoporosis in men. The damage these medications cause may be due to their direct effect on bone, muscle weakness or immobility, reduced intestinal absorption of calcium, a decrease in testosterone levels or, most likely, a combination of these factors.
Bone mass often decreases quickly and continuously with ongoing use of glucocorticoid medications, with most of the bone loss in the ribs and vertebrae. About one-third of patients have evidence of vertebral fractures after 5 to 10 years of treatment with glucocorticoids. The risk of hip fracture is increased nearly three-fold. Therefore, patients taking these medications should talk to their doctor about having a bone mineral density (BMD) test; men should also be tested to monitor testosterone levels, as glucocorticoids often reduce testosterone in the blood.
A treatment plan to minimize damage to bone during long-term glucocorticoid therapy may include using the minimal effective dose, discontinuation of the drug when practical, and topical (skin) administration if possible. Adequate calcium and vitamin D nutrition is important, as these nutrients help reduce the impact of glucocorticoids on bone. Other possible treatments include testosterone replacement and medication. Alendronate and risedronate are two bisphosphonate medications approved by the U.S. Food and Drug Administration for use by men and women with glucocorticoid-induced osteoporosis.
Hypogonadism refers to abnormally low levels of sex hormones. It is well known that loss of estrogen causes osteoporosis in women. In men, reduced levels of the sex hormones may also cause osteoporosis. In fact, it is estimated that up to 30 percent of men with osteoporotic vertebral fractures have low testosterone levels. While it is natural for testosterone levels to decrease with age, there should not be a sudden drop in this hormone comparable to the drop in estrogen experienced by women at menopause. However, medications like steroids (discussed above), cancer treatments (especially for prostate cancer), and many other factors can affect testosterone levels.
Testosterone replacement therapy may be helpful in preventing or slowing bone loss. Its success depends on factors such as age and how long testosterone levels have been reduced. Also, it is not yet clear how long any beneficial effect of testosterone replacement will last; therefore, doctors will usually treat the osteoporosis directly, using medications approved for this purpose.
Recent research suggests that estrogen deficiency may be a cause of osteoporosis in men. For example, estrogen levels are low in men with hypogonadism and may play a part in bone loss. Osteoporosis has been found in some men who have rare disorders of estrogen action. Therefore, the role of estrogen in men is under active investigation.
There is a wealth of evidence that alcohol abuse may decrease bone density and lead to an increase in fractures. Low bone mass is found in 25 to 50 percent of men who seek medical help for alcohol abuse. One early study found the bone mass of young alcoholic males to be comparable to that of elderly females.
In cases where bone loss is linked to alcohol abuse, the first goal of treatment is, of course, to help the patient stop--or at least reduce--his consumption of alcohol. More research is needed to determine whether bone lost to alcohol abuse will rebuild once drinking stops, or even whether further damage will be prevented. It is clear, though, that alcohol abuse causes many other health and social problems, so quitting is ideal. A treatment plan may also include a diet with lots of calcium- and vitamin D-rich foods, calcium supplementation, and physical exercise, and would discourage smoking.
Bone loss is more rapid, and rates of hip and vertebral fracture are higher, among men who smoke, although more research is needed to determine exactly how smoking damages bone. Tobacco, nicotine and other chemicals found in cigarettes may be directly toxic to bone or they may inhibit absorption of calcium and other nutrients needed for bone health. Quitting is the ideal approach, of course, as smoking is harmful in so many ways. But again, as with alcohol, it is not known whether quitting smoking leads to reduced rates of bone loss or to a gain in bone mass.
Several nutrients, including amino acids, calcium, magnesium, phosphorous and vitamins D and K are important for bone health. Diseases of the stomach and intestines can lead to bone disease when they impair absorption of these nutrients. Treatment for bone loss in this case may include supplementation of the poorly absorbed nutrient(s).
Hypercalciuria is a disorder that causes too much calcium to be lost through the urine, which makes the calcium unavailable for building bone. It is more than twice as common in men as in women. Patients with hypercalciuria should talk to their doctor about having a BMD test and, if bone density is low, discuss treatment options.
Weight-bearing exercise is essential for maintaining healthy bones; without it, bone density may rapidly decline. Prolonged bed rest (following fractures, surgery, spinal cord injuries or illness) or immobilization of some part of the body often results in significant bone loss. It is crucial to resume weight-bearing exercise (such as walking, jogging, dancing and weight-lifting) as soon as possible after a period of prolonged bed rest. If this is not possible, patients should work with their doctor to minimize other risk factors for osteoporosis.
What Are the Risk Factors for Men?
Several risk factors have been linked to osteoporosis in men:
- Chronic diseases that affect the kidneys, lungs, stomach, and intestines or alter hormone levels.
- Undiagnosed low levels of the sex hormone testosterone.
- Unhealthy lifestyle habits (e.g., smoking, excessive alcohol use, low calcium intake, inadequate physical exercise).
- Age: The older you are, the greater your risk.
- Heredity: A son is almost four times as likely to have low bone mineral density (BMD) if his father has low BMD, and nearly 8 times as likely if both parents have low BMD.
- Race: Caucasian men appear to be at particularly high risk, but all men can develop this disease.
How Is Osteoporosis Diagnosed in Men?
Osteoporosis can be effectively treated if it is detected before significant bone loss has occurred. A medical work-up to diagnose osteoporosis will include a complete medical history, x-rays, and urine and blood tests. The doctor may also order a BMD test or bone mass measurement. A special type of x-ray, the BMD test requires trace amounts of radiation. It is safe, accurate, quick, painless, and noninvasive and can be used to detect low bone density, predict risk for future fractures, diagnose osteoporosis and monitor the effectiveness of treatments.
It is increasingly common for women to be diagnosed with osteoporosis or low bone mass using a BMD test, often at mid-life when doctors begin to watch for signs of bone loss. In men, however, the diagnosis is often not made until the patient sees his doctor complaining of back pain or until a fracture occurs. This makes it especially important for men to inform their doctor about risk factors for developing osteoporosis, loss of height or change in posture, a fracture, or sudden back pain.
Some doctors may be unsure how to interpret the results of a BMD test in male patients. For example, it is not known whether the guidelines used to diagnose osteoporosis or low bone mass in women (developed by the World Health Organization) are also appropriate for men. Until that question is answered--and until separate criteria are established for men, if necessary--most experts suggest using the WHO criteria for men.