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Osteoporosis

What is Osteoporosis?

Osteoporosis is a disease that results in thin and brittle bones that break more easily than normal. About 1.4 million Canadians, including 1 in 4 women and 1 in 8 men over 50 years of age have osteoporosis. Elderly women are at greatest risk for the harmful effects of the disease. In fact, the rate of death caused by bone fractures related to osteoporosis is higher than the rate of death caused by breast cancer and cancer of the ovaries combined in this population of women.

What Causes Osteoporosis?

Osteoporosis occurs when the cells that break down bone (osteoclasts) work faster than the cells that make bone (osteoblasts). The thickness of bone is called 'bone mineral density'. For every 10-12% decrease in bone mineral density, there is approximately double the risk for a bone fracture at the hip or spine or other location.

There are Two Main Types of Osteoporosis:

Type 1 osteoporosis is also known as postmenopausal osteoporosis and is caused by the decline in estrogen that takes place during menopause. A reduction in estrogen causes the cells that break down bone to work more quickly. This type of osteoporosis most often occurs between the ages of 51 and 75 years.
Type 2 osteoporosis is caused by aging and usually occurs in people over 60 years. It is caused by a slowing down of the cells that lay down bone.

Can Osteoporosis Be Prevented?

Although there are some risk factors for osteoporosis such as increasing age, family history, certain medical conditions and medications that we can't do anything about, there are some good prevention strategies that you can put into place to reduce your risk of osteoporosis:

Consume enough calcium throughout life to give bones the raw material they need for growth.
Consume enough vitamin D throughout life to allow the body to absorb the calcium it needs.
Exercise regularly to help strengthen bones.
Quit smoking to prevent bone breakdown.
Use alcohol and caffeine in moderation.

Age Recommended Daily Calcium Intake

7-9 700 mg

10-12 900 mg (boys) | 1200-1400 mg (girls)

13-16 1200-1400 mg

17-18 1200 mg

19-49 1000 mg

50 or older 1000-1500 mg

Calcium is available from a variety of foods. For example, one cup of milk contains about 315 mg of calcium. You can estimate your daily calcium intake from the 'calcium calculator' found on the Osteoporosis Society of Canada website at www.osteoporosis.ca

The best source of vitamin D is sunshine. For people who aren't able to get outside much, 400-800 i.u. Vitamin D is recommended. Your PROfile® Pharmacist will be happy to discuss your calcium and vitamin D needs with you and recommend appropriate supplements.

Medication

The prescription medications available for the treatment of osteoporosis work by slowing down the cells that break down bone (osteoclasts).

Hormone Replacement Therapy was traditionally the first choice for prevention and treatment of postmenopausal osteoporosis. Recently, a large study revealed that use of hormone replacement therapy consisting of conjugated equine estrogen and medroxyprogesterone taken once daily increased risk of breast cancer in 8 extra women out of 10,000 per year compared to women who did not take this medication. With this in mind, the Society of Obstetricians and Gynecologists of Canada recommend that short-term use (2-3 years) of hormone replacement remains an option for osteoporosis prevention, and 'may be considered in conjunction with benefits, risks, tolerability, and the costs of alternatives'.

Raloxifene is a medication known as a Selective Estrogen Receptor Modifier (SERM) and has been designed to reduce fracture risk associated with osteoporosis without increasing the risk of breast cancer. In fact, studies are ongoing to determine whether raloxifene actually offers protection from breast cancer.

Bisphosphonates are medications that are non-hormonal in nature and therefore are beneficial for both women and men at risk of, or suffering from osteoporosis. Examples include etidronate, alendronate and risedronate. Calcium and mineral supplements should be avoided within 2 hours of taking these medications as they interfere with absorption of the medication. Talk with your PROfile® Pharmacist about the best way to take your bisphosphonate medication.

Calcitonin-Salmon Nasal Spray - Calcitonin is a naturally occurring human hormone that helps to build bones. This medication is approved for use only in women who are at least 5 years past the start of menopause.

Natural Therapies - Isoflavones and natural progesterone are the two most popular natural therapies for prevention and treatment of osteoporosis. Scientific studies are being performed to more clearly define the role of these medications.

If I Want to Stop Taking Hormone Replacement Therapy, How Should I Do It?

You should always talk with your doctor before stopping any medication that has been prescribed for you. If you and your doctor decide it would be best for you to stop taking hormone replacement therapy, it is a good idea to 'wean' off the medication. For example, your doctor may suggest that you decrease your dose slowly or use continuous combined hormone replacement therapy on alternate days for a period of several weeks. This will prevent menopausal type symptoms that might occur as a result of the sudden drop in estrogen levels. If you have been taking hormone replacement therapy on a daily basis without a monthly break, you will likely experience symptoms similar to menstrual bleeding as a result of withdrawal of the hormones.

How Is Bone Mineral Density Measured?

This measurement is the single best predictor of osteoporosis risk. It is usually done with the help of x-ray devices that emit very low levels of radiation (one-tenth that of a normal chest x-ray). Currently, due to the expense involved and the availability of the equipment, bone mineral density testing with x-ray is recommended only for people at increased risk of osteoporosis. Heel ultrasound estimations of bone mineral density are easier to do, more readily available, less expensive, but not as exact. Heel ultrasound can determine whether a person should be further investigated for the possibility of osteoporosis.

What Medications or Health Conditions Puts One at an Increased Risk for Osteoporosis?

Corticosteroid medications such as prednisone or dexamethasone taken internally for long periods of time can cause a reduction in bone mineral density.

Other drugs that increase risk include levothyroxine, anticonvulsants, methotrexate, heparin and lithium. Medical conditions that increase the risk of osteoporosis include Cushing's disease, hyperparathyroidism, rheumatoid arthritis, multiple myeloma, leukemia and type 1 diabetes.