September 18, 1998

Contrary to popular belief, osteoporosis is not an inevitable part of aging and today osteoporosis experts and health advocates will begin drafting a plan to prevent the disease in California.

Osteoporosis thins the bones, makes them brittle, and leads to 1.5 million bone fractures each year in this country. Simple falls for people with osteoporosis can lead to hip, spine and wrist fractures. Twenty percent of those with osteoporosis-related hip fractures die within a year of their injury.

This bone-thinning disease can creep up, silently draining your bones of calcium over decades. Your backbones slowly weaken. Your spine begins to bow. Almost imperceptibly, your posture becomes slightly stooped. You "grow shorter."

Osteoporosis means "porous bones." Bones that were once strong become weak and brittle - so brittle that even mild stresses, like bending to pick up a newspaper, lifting a vacuum or coughing, can cause a fracture.

The strength of your bones relates to the mass or density of your bones. And that results in part from calcium, phosphorus and other minerals in bone. In osteoporosis, bone strength is decreased because your bones contain fewer minerals, and they slowly lose their internal supporting structure.

"Osteoporosis is a serious disease that affects millions of women," said State Health Director Kim Belshé. "Every American woman has a one-in-two chance of suffering an osteoporotic fracture during her lifetime. Prevention and early detection can save women from pain, isolation, loss of independence and premature death."

Scientists have yet to learn all the reasons for loss of bone strength, but the process involves how bone is made.

Bone is continually changing - new bone is made and old bone is broken down, a process called "remodeling" or "bone turnover." Bone cells called osteoclasts dissolve or "resorb" old bone cells, leaving tiny cavities. Then bone cells called osteoblasts line these cavities with a soft honeycomb of protein fibers that becomes hardened by mineral deposits. This mineral-hardened honeycomb, which accounts for your bones' strength, depends on an adequate supply of calcium. Estrogen also plays a key role in bone health by slowing resorption of old bone and promoting new growth.

A full cycle of bone remodeling takes about 2 to 3 months. When you're young, your body makes new bone faster than it breaks down old bone, and your bone mass increases. You reach your peak bone mass in your mid 30s. After than, bone remodeling continues, but you lose slightly more than you gain about a .3 percent to .5 percent loss a year.

At menopause, when estrogen levels drop, bone loss accelerates to about 1 percent to 3 percent a year. Around age 60, bone loss slows but doesn't stop. By advanced age, women have lost between 35 percent and 50 percent of their bone mass and men, 20 percent to 35 percent.

Your risk of developing the disease depends on how much bone mass you attained between ages 25 and 35 (peak bone mass) and how rapidly you lose it later. The higher your peak bone mass, and the more bone you have "in the bank" and the less likely you'll be to develop osteoporosis as you lose bone during normal aging.

There is no current statewide effort to prevent osteoporosis in California. In an effort to prevent this emerging disease, the State Department of Health Services, Dairy Council California and California Center of Health improvement convened osteoporosis experts and health advocates at Sierra Health Foundation to develop a blueprint for preventing this disease.

The best defense against osteoporosis is a diet rich in calcium and Vitamin D combined with regular weight-bearing exercise and resistance training. Foods rich in calcium and Vitamin D include dairy foods such as low-fat milk, yogurt and cheese. Weight-bearing exercise includes walking and aerobic dance. Resistance training includes weight lifting.

For more information on osteoporosis prevention, call Peggy Agron, MA, RD, co-director of Project LEAN (Leaders Encouraging Activity and Nutrition) at (916) 327-3020. Project LEAN is a program of the State Health Department.

For educational information material on osteoporosis you can check out these resources:

The National Osteoporosis Foundation. 800-223-9994. Web site: www.nof.org

The Osteoporosis and Related Bone Diseases National Resource Center. 800-624-2663. Web site: www.osteo.org

Information contained in this article was derived from a "Medical Essay, Supplement to Mayo Clinic Health Letter." October 1997.

How do you know if you have osteoporosis?

Doctors can detect early signs of osteoporosis with a simple, painless bone density test.

Who should have a test and at what age is somewhat controversial. If you're at menopause and undecided about hormone replacement therapy, a test can be helpful. But if you're already taking hormone therapy, you probably don't need one.

The National Osteoporosis Foundation recommends a bone density test if you aren't taking estrogen and any of the following apply to you:

You use medication that can cause osteoporosis

You have Type I diabetes, liver disease, kidney disease, or a family history of osteoporosis

You experienced early menopause.

You should also have a test if X-rays or other conditions suggest osteoporosis.

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