Boning Up

When bones lose calcium and get thinner the process is called osteoporosis. Over 26 million Americans have osteoporosis, and the overwhelming majority are women. This is a common phenomenon as people age, and the risk of breaking bones increases because of it. By age 65, one third of women will have a vertebral fracture, and by their 80s, another one third will have fractured a hip. Roughly, 1 in 8 men older than age 50 has osteoporosis. However, there are ways that both men and women can decrease the degree of bone thinning as they age.

Unfortunately, several of the most common risk factors for osteoporosis are out of our control: genetic predisposition, Caucasian or Asian ethnicity, and low body mass index (or thin body frame). Estrogen deficiency in women and testosterone deficiency in men are also major risk factors for loss of bone density. Though both of these hormones can be replaced with medications, each patient needs to understand the individual risks and benefits of such replacement. Certain drugs that patients may require for other health problems, such as steroids, and anti seizure medications may also cause bone loss. And chronic kidney insufficiency, certain forms of inherited arthritis, malabsorption, and other hormonal imbalances can lead to bone loss as well. But I want to stress the importance of lifestyle habits in maintaining strong bones overtime.

Excessive alcohol use, low calcium intake, cigarette smoking, and sedentary lifestyles are all associated with bone loss. Do you realize that most Americans fail to meet the recommended daily allowance of calcium intake after age 10? Also, since Vitamin D is necessary to absorb calcium from the intestines, inadequate consumption of this vitamin can also lead to osteoporosis. It has been estimated that 40% of the men and 30% of the women with hip fractures are Vitamin D-deficient (NEJM 1997). Inactivity leads to an increased loss of body calcium through the kidneys. Additionally, people who exercise with regularity seem to have a 10–20% increased bone density compared to their sedentary peers; bone appears to respond to regular weight-bearing activities by maintaining strength and density and loses these attributes in inactive individuals. “Use it or lose it” certainly applies to bone strength.

Though high alcohol consumption is considered a risk factor, even moderate (1 to 2 drinks/day) alcohol consumption on a chronic basis can increase osteoporosis risk even in young men and women. The precise way that alcohol affects bone metabolism is not clear–but it is probably a combination of direct effects on bone cells and indirect effects on several of the mineral-regulating hormones produced by the body.

Cigarette smoking is an especially important risk factor in women. Female smokers have lower levels of estrogen than nonsmokers and tend to go through menopause at earlier ages. And, while we’re discussing voluntary habits, perhaps elderly individuals who consume large quantities of caffeine (especially coffee) on a regular basis may be increasing their loss of calcium in their urine. The diuretic effect of caffeine promotes loss of calcium in the urine to some degree in all individuals, but this effect is compounded in aging individuals whose bodies are less efficient at blocking the calcium loss.

So, what can we do voluntarily to decrease our loss of bone mass over time? Twenty to thirty minutes of regular weight-bearing exercise three times a week helps to improve muscular strength and balance and to protect bone mass. Premenopausal women, postmenopausal women on estrogen, and all men need 1,000 to 1,200 mg of calcium daily. Postmenopausal women not taking estrogens should receive 1,500 to 2,000 mg of calcium daily. And Vitamin D supplementation is important to aid absorption of the calcium by the body. Don’t smoke, and be moderate in your consumption of both caffeine and alcohol. There are a variety of medications on the market now to preserve bone mass and to actually help rebuild bone mass in people who already have osteoporosis. But, regardless of your medication regimen, you can bone up with a healthy lifestyle. There is a Spanish proverb “A man too busy to take care of his health is like a mechanic too busy to take care of his tools.” Preventive maintenance is always worth the effort.

Stephen L. Hines, M.D.
June 2000