Osteoporosis: New Treatments, Changing Lifestyle

by Food and Drug Administration (FDA)

Consider an insidious condition that drains away bone — the hardest, most durable substance in the body. It happens slowly, over years, so that often neither doctor nor patient is aware of weakening bones until one snaps unexpectedly. Unfortunately, this isn't science fiction. It's why osteoporosis is called the silent thief.

And it steals more than bone. It's the primary cause of hip fracture, which can lead to permanent disability, loss of independence, and sometimes even death. Collapsing spinal vertebrae can produce stooped posture and a "dowager's hump." Lives collapse too. The chronic pain and anxiety that accompany a frail frame make people curtail meaningful activities because, in extreme cases, the simplest things can cause broken bones: Stepping off a curb. A sneeze. Bending to pick up something. A hug. "Don't touch Mom, she might break" is the sad joke in many families.

Osteoporosis leads to 1.5 million fractures, or breaks, per year, mostly in the hip, spine and wrist, with the cost of treatment estimated at $17 billion and rising, according to the National Institutes of Health (NIH). It threatens 34 million Americans, mostly older women, but older men get it too. One in 2 women and 1 in 4 men older than 50 will suffer a vertebral fracture, according to the NIH. These numbers are predicted to rise as the population ages.

Osteoporosis, which means "porous bones," is a condition of excessive skeletal fragility resulting in bones that break easily. A combination of genetic, dietary, hormonal, age-related, and lifestyle factors all contribute to this condition. The osteoporosis seen in postmenopausal women is the most common and best-studied, but there are other causes that may be treated differently.

Changing attitudes and improving technology are brightening the outlook for people with osteoporosis. Nowadays, many women live 30 years or more — perhaps a quarter to a third of their lives — after menopause. Improving the quality of those years has become an important health care goal. Although some bone loss is expected as people age, osteoporosis is no longer viewed as an inevitable consequence of aging. Diagnosis and treatment need no longer wait until bones break.

There is no cure or proven preventive treatment for osteoporosis, but the onset can be delayed and the severity diminished. Most important, early intervention can prevent devastating fractures. The Food and Drug Administration has revised labeling on foods and supplements to provide valuable information about the level of nutrients that help build and maintain strong bones. The FDA has also approved a wide variety of products to help diagnose and treat osteoporosis, including several in the last few years.

Osteoporosis has been described as a geriatric disease with an adolescent onset, highlighting the importance of beginning to take steps — in exercise and diet — early in life to reduce its disabling impact in later years.

Bone Life

Bone consists of a matrix of fibers of the tough protein collagen, hardened with calcium, phosphorus and other minerals. Two types of architecture give bones strength. Surrounding every bone is a tough, dense rind of cortical bone. Inside is spongy-looking trabecular bone. Its interconnecting structure provides much of the strength of healthy bone, but it is especially vulnerable to osteoporosis.

"We tend to think of the skeleton as an inert erector set that holds us up and doesn't do much else. That's not true," says Karl L. Insogna, M.D., director of the Bone Center at Yale School of Medicine in New Haven, Conn. Every bit as dynamic as other tissues, bone responds to the pull of muscles and gravity, repairs itself, and constantly renews itself.

Besides protecting internal organs and allowing us to move about, bone is also involved in the body's handling of minerals. Of the 2 to 4 pounds of calcium in the body, nearly 99 percent is in the teeth and skeleton. The remainder plays a critical role in blood clotting, nerve transmission, muscle contraction (including heartbeat), and other functions. The body keeps the blood level of calcium within a narrow range. When needed, bones release calcium.

A complex interplay of many hormones balances the activity of the two types of cells — osteoclasts and osteoblasts — responsible for the continuous turnover process called remodeling. Osteoclasts break down bone, and osteoblasts build it. In youth, bone building prevails. Bone mass peaks by about age 30, then bone breakdown outpaces formation, and density declines, since the volume of bone remains about the same.

The skeleton is like a retirement account for minerals, but in our skeletal "account" we can deposit bone faster than we withdraw it only during our first three decades. After that, withdrawals are greater than deposits, and all we can do is try to minimize the net loss. Osteoporotic fractures are the sign of the bankruptcy that occurs when too little bone is formed during youth, or too much is lost later, or both.

"You've got to get as much bone as you can and not lose it," Insogna says. "The most important risk factor for osteoporosis is a low bone mass."

"The upper limit of bone mass that you can acquire is genetically determined," says Mona S. Calvo, Ph.D., a calcium expert in the FDA's Center for Food Safety and Applied Nutrition. "But even though you may be programmed for high bone mass, other factors can influence how much bone you end up with," she says. (See "Reducing Your Risk.") For instance, men tend to build greater bone mass, which is partly why more women face osteoporosis.

But there's another reason. With the decline of the female hormone estrogen at menopause, usually around age 50, bone breakdown markedly increases. For several years, women lose bone two to four times faster than they did before menopause. The rate usually slows down again, but some women may continue to lose bone rapidly. By age 65, some women have lost half their skeletal mass.

About the Author

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