The following questions were answered by physicians from the Osteoporosis Program at Women's College Hospital:

Q. What is the relationship between bone mass and fracture risk?

A. There is a direct relationship between bone mass and fragility fractures. For each standard deviation decline in BMD, there is about a two-fold increase in the risk of fracture. For example, with a T-score of -1.00, the fracture risk doubles, while at a T-score of -3.00, the fracture risk increases to 8 times that of a young adult.

Although people sometimes compare measuring bone density to assess a person’s risk of osteoporosis with measuring cholesterol to assess a person’s risk of cardiovascular disease, the relationship between bone mass and osteoporosis is more direct.

Q. Can calcium and exercise prevent/treat postmenopausal osteoporosis?

A. Lifetime management to maintain bone should include:

• avoiding lifestyle risk factors (no smoking, low intake of alcohol and caffeine)
• eating calcium-rich foods and getting enough vitamin D to enhance calcium absorption
• exercising to improve balance
• daily weight-bearing exercise

Through diet and supplements, postmenopausal women require 1,200 mg to 1,500 mg of elemental calcium and 400 to 800 international units (IU) of vitamin D daily. The typical North American diet contains 200 mg to 300 mg of elemental calcium (one glass of milk has 300 mg).

Daily calcium is important to prevent bone loss associated with the decrease in estrogen in postmenopausal women but it is not enough on its own. High calcium intake may decrease the rate of bone loss in older adults; however, it has not been shown to prevent age or menopause-related bone loss on a regular basis.

Several studies show that weight-bearing exercise has a positive effect on bone density, making bones stronger and less fragile. Exercise has also been shown to improve the effect of other therapies (for example, combined with drug treatment).

Increased exercise is also important for:

• easy body movement
• an increase in muscle strength
• improvement in walking and with balance
• stronger muscles, which lead to a decreased risk of falling

Q. How can I prevent fractures?

A. The best way to avoid a fracture is to avoid falling (to prevent hip and wrist fractures) and to maintain good back care/posture (to minimize the risk of spinal fractures.) Use these links for practical tips on preventing falls and on modifying your daily activities to protect your back.

Some medical conditions and medications can interfere with strength, co-ordination, posture and balance, which can increase a person’s risk of falling and fracturing a hip. A visual impairment can also increase the risk of a fall and fracture. Discuss these issues with your health-care provider.

For older people, fall prevention strategies are an important part of the treatment plan. The best way to develop these strategies is to have an occupational therapist assess your home or workplace. A physiotherapist can explain how to exercise to improve your strength, balance and flexibility.