What is Osteoporosis?

Each year thousands of middle-aged and elderly Americans experience a sudden, unexpected bone fracture. Often the underlying cause of the fracture is a disease called osteoporosis. A major health problem, osteoporosis reduces bone mass causing bones to become thin and fragile and more likely to break.

If left untreated, osteoporosis can become a debilitating disease. For example, lifting or bending to pick up a heavy object can cause a spinal fracture. In fact, the bone can become so thin that a person can fracture the spine simply by carrying his or her own weight (Fig. 1). These types of fractures usually occur in the hip, spine, and wrist, but osteoporosis affects all bone in the skeletal system, placing it at a higher risk of fracture.

What causes osteoporosis?
As part of the natural aging process your bones become weaker and less dense. Bone is living tissue that provides structural support for muscles, protects vital organs, and stores much needed calcium. Diet, exercise, and your overall lifestyle affect bone growth and a bone's ability to heal. You build and store bone efficiently until around age 30, then as you age your bones begin to break down faster than new bone can be formed. Therefore, the older you are, the greater your risk of osteoporosis.

Calcium is an important mineral nutrient for bone formation, but it also helps muscle contraction, blood clotting, and nerve functions. Most of your calcium supply is stored in your bones; however, if the body does not take in enough calcium, it will draw its supply from the bone. Calcium alone cannot prevent or cure osteoporosis, but a history of low calcium intake can put you at an increased risk for osteoporosis.

Bone mass is directly affected by a decrease in the female hormone estrogen. In women, bone loss accelerates after menopause when your ovaries stop producing estrogen. An estrogen deficiency can occur after natural menopause or after the surgical removal of both ovaries. An estrogen imbalance can also be found in women with eating disorders and in women who do not have a regular menstrual cycle (Fig. 2). Often, estrogen replacement therapy is prescribed to prevent or reduce bone loss. Men also experience similar bone loss if the male hormone testosterone becomes deficient.

A major cause of osteoporosis is the lack of accumulated bone density before age 30. Therefore, less bone is available when bone begins to break down faster than it is formed. For young adults, especially women, building bone mass is a critical factor in protecting yourself against osteoporosis.

Are you at risk?
Your chances of developing osteoporosis are greater if you answer yes to any of the following questions:

• Are you a woman? Women usually have less bone tissue and lose bone more rapidly than men, putting them at a higher risk for osteoporosis.
• Are you thin or do you have a small frame? If so, you tend to have more fragile bones.
• Are you Caucasian or Asian? If so, your risk is higher, although African Americans and Hispanic Americans are also at risk.
• Are you aged 50 or older? Your bones become weaker and less dense as you age.
• Do you have a family history of osteoporosis or are you susceptible to fracture? If so, it may be hereditary. Often, young women whose mothers had vertebral fractures also have reduced bone mass.
• Does your body no longer produce the hormone estrogen? If you are postmenopausal; if you stop menstruating because of conditions such as anorexia or bulimia (eating disorders) or because of excessive physical exercise; or if you experience an abnormal absence of your menstrual cycle, you are at a greater risk for osteoporosis.
• Is your diet low in calcium?
• Do you use certain medications, such as corticosteroids and anticonvulsants; medications to treat disorders such as rheumatoid arthritis, endocrine disorders (underactive thyroid), seizure disorders, and gastrointestinal diseases? If so, you may experience side effects that can damage bone and lead to osteoporosis.
• Are you a man with low testosterone levels?
• Do you smoke cigarettes, use alcohol excessively, or get little or no weight-bearing exercise? If so, you increase your chances of developing osteoporosis.

Can osteoporosis be prevented?
Building strong bones during childhood and adolescence can be the best defense against developing osteoporosis later. However, despite your age, you can take action now to prevent or slow the effects of osteoporosis. One action alone is not enough to prevent or slow osteoporosis, but applying all of these principles may. You should eat a balanced diet that is rich in calcium and vitamin D. You should regularly participate in a weight-bearing exercise program, and live a healthy lifestyle that includes no smoking or excessive alcohol intake. And if you become at risk for osteoporosis, you should have a bone density test and take any prescribed medication necessary. Together, these practices will not only help you prevent osteoporosis, they will help you live a happier, healthier life.

John M. Henderson, DO, FAAFP
Columbus, Georgia

References:
1. Sinaki M, Dale DA, Hurley DL. Living with Osteoporosis. Philadelphia, PA: BC Decker, Inc; 1988.
2. Aloia JF. Osteoporosis: A Guide to Prevention & Treatment. Champaign, IL: Leisure Press; 1989.
3. Marcus R, Feldman D, Kelsey J. Osteoporosis. New York, NY: Academic Press; 1996.