Osteoporosis is a gradual thinning and weakening of the bones resulting from excessive loss of bone mass. Bone thinning generally begins in the mid-thirties and continues into old age. The process tends to be slow, painless and can take many years before it is detected. Often, Osteoporosis is only noticed when a bone breaks with very little trauma.

From childhood to mid-twenties, each of our 206 bones continually undergoes a process of building up and breaking down. Generally, the building process outperforms the breakdown process until bone mass reaches a peak around age 30 for women and age 35 for men. Our peak bone mass is maintained throughout our forties until it begins to deplete as calcium and other components are withdrawn from the bone in the breakdown process. This natural decline in bone mass can become a problem if insufficient bone mass was established in the first third of our lives or in cases where the process of breakdown is overly rapid.

Bone mass depletion weakens and thins all bones; however, the wrists, hips and spine are most susceptible. Weakening is apparent when a minor fall results in a fracture to the hip or wrist, when a hunched back develops, when there is loss of height, or when clothes don't fit properly. For many sufferers of osteoporosis, normal day-to-day activities can come to an abrupt halt from a broken bone. Bone fractures can result in extreme pain, hospitalization, extensive rehabilitation, serious disabilities, and even death. Although many individuals with osteoporosis never reach this alarming stage of the disease, they are still at a dramatically increased risk of fracturing a bone.

Who Is At Risk?

Osteoporosis can strike both men and women at any age, but it most often affects Caucasian and Asian women over 50. During the first 3 to 5 years after menopause, when the ovaries are no longer producing estrogen, loss of bone mass in women can be five to ten times greater than in men. Nearly one-quarter of women over sixty and half over seventy will develop osteoporosis. At the same ages, approximately one-fifth of men will be affected. Women with small body frames, or who are considered unusually thin, are at a greater risk of developing osteoporosis. In addition, people who are bedridden, confined to a wheelchair, or who lead inactive lifestyles are also at a higher risk.

Risk Factors for Developing Osteoporosis

Risk factors for developing osteoporosis are often described as "modifiable" and "non modifiable." Adjusting our lifestyles to eliminate or at least lower the modifiable risk factors can decrease the risk of developing Osteoporosis.

Modifiable Risk Factors

• Sedentary Lifestyle. Bones - much like muscle - tend to weaken from lack of regular physical activity.
• Smoking and Excessive Alcohol Consumption. Each interferes with the body's ability to maintain normal, healthy bones.
• Poor Nutrition. People without adequate calcium or vitamin D in their diets are more likely to develop osteoporosis. Calcium is the building block for bones and teeth and is not only required for growth but also for maintaining bone strength. Vitamin D is necessary for calcium absorption.
• Estrogen Deficiency often occurring after menopause. Estrogen is needed to maintain bone strength and without it, bones begin to lose calcium. If you are going through menopause it is a good idea to talk about your options with your doctor.

Non-Modifiable Risk Factors

• Age. Incidence increases with age.
• Gender. Most common in females
• Hereditary. Individuals with a family history of osteoporosis are at greater risk.
• Race. Osteoporosis is most common in Caucasians and Asians.
• Physical Stature. More common in thin, small-boned people whose bones can be more fragile and break more easily.

In addition to these, other factors to consider are:

• Medical History. Conditions such as overactive thyroid gland, liver disease, or anorexia nervosa can sometimes lead to osteoporosis. Long term steroidal therapy can also lead to osteoporosis. If you have any of these conditions or you are using steroid medications, consult with your physician about your concerns.
• Previous Bone Fracture. A fracture due to a minor fall may be a sign of weakening bones.

Prevention Is The Best Defence

The main goal in preventing Osteoporosis is to build strong bones in the first third of our lives and prevent excessive loss of bone mass as we age. The chances of developing Osteoporosis can be determined at an early age. Building bone mass early enables us to better withstand bone loss as we age. Other steps to take are:

• Regular, moderate weight bearing exercises such as walking, swimming, or low impact aerobics and weight training, can benefit your bones and your heart. Although exercise should be a part of your entire life, it becomes particularly important as you age.
• Women reaching menopause may wish to discuss the benefits of hormonal replacement therapy with their physician.
• Stop smoking and reduce your alcohol intake.
• Increase your dietary calcium. Keep your bones strong by consuming foods rich in calcium such as dairy products, broccoli, sardines, bread, soybeans and peanuts.
• Consider taking a calcium supplement.

Quick Facts about Osteoporosis

• Osteoporosis is a Latin word meaning 'porous bones'
• Over one million Canadians suffer from osteoporosis
• Osteoporosis is the major underlying cause of bone fractures in post-menopausal women and the elderly
• By age 65, the average man has approximately 91% of his bone mass, while the average woman has only about 74%.
• It is estimated that over three quarters of a million Canadian women suffer from some degree of Osteoporosis.

For information about Calcium and its role in preventing Osteoporosis, read our Calcium article.

Compiled by Colin Holyk
Kerrisdale Pharmacy, Vancouver, B.C.
Edited by Megan Stiles
Last Reviewed: September 2001