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bone loss, porous bones
Osteoporosis is the loss of bone density or thinning of the bones. This causes weakness, and eventually the involved bone may break.
What is going on in the body?
Bones go through a constant state of bone loss and regrowth. People reach their peak bone mass by about age 30. After the age of 30, bone loss slowly begins to occur. This loss, if it becomes severe, can lead to a condition called osteoporosis. The bones become thin and fragile and may break easily. Bone loss occurs initially very slowly for both women and men. After the age of 65-70 years, men begin to lose bone more rapidly. Women, on the other hand, begin to lose bone more rapidly once they reach menopause, and the body's oestrogen level falls. Women may also begin to lose bone more rapidly if they have their ovaries taken out during surgery when they are younger.
Bone is made up of calcium and proteins. There are two types of bone: compact and spongy. Each bone in the body has both types of bone in different amounts. Compact bone looks solid and hard. This is the outer shell of a bone. Spongy bone is the inner part of the bone and is full of tiny holes like a sponge. The first signs of osteoporosis are seen in bones that have a lot of spongy bone, such as the hip, spine and wrist.
Osteoporosis affects many Australians. More women than men get osteoporosis. One third of women older than 65 will have a fracture of the spine. One in 5 women over the age of 70 will have a fracture of the hip and as many as 1 in 3 women over the age of 80 will suffer a hip fracture during their lifetime. Nearly one in five women with a hip fracture will die within 6 months. The cause of death is related to problems that occur because people are not able to get around as well. Some of the most common problems are blood clots and pneumonia.
What are the signs and symptoms of the disease?
Bone loss produces few symptoms but leads to reduced bone strength. Bones are more likely to break. Symptoms occurring late in the disease include:
What are the causes and risks of the disease?
- fracture of a hip, a vertebra in the spine or the wrist, sometimes without falling or any trauma to the area
- low back pain
- neck pain
- loss of height (usually 2.5 to 5.0 cms from height at age 30)
- stooped posture, known as dowager's hump
- slight curvature of the upper back
- dentures that do not fit as well
- bone pain or tenderness
Women are more at risk for osteoporosis than men. This is because their bone mass is lower even when it is at its peak, and their bones are lighter. The following are risk factors that increase the chances of getting osteoporosis:
What can be done to prevent the disease?
- menopause. During menopause, the ovaries stop making oestrogen, which normally protects against bone loss.
- removal of the ovaries.
- low-calcium diet.
- race, with white and Asian women being at highest risk.
- sedentary lifestyle.
- slender build (less than 60kgs).
- eating disorders such as anorexia and bulimia.
- family history of osteoporosis.
- medications such as corticosteroids, thyroid medication, certain medications for seizures, diuretics, a group of medications used for high blood pressure, and the long term use of heparin which is a blood thinner.
- medical problems, such as hyperthyroidism and hyperparathyroidism. Hyperthyroidism is a condition in which the thyroid makes too much thyroid hormone. This can cause thinning of the bones. Hyperparathyroidism is a condition in which the parathyroid gland, a gland in the neck, makes too much parathyroid hormone. Too much of this hormone can effect calcium levels in the bloodstream, and cause thinning of the bones.
- bone cancers.
It is very important, beginning at a young age, to build and keep as much bone as possible. Exercise, adequate calcium intake, and hormone replacement therapy (HRT) may help to prevent osteoporosis.
Exercise increases bone mass before menopause, and slows bone loss after menopause. Bones become stronger after exercise, just like muscles. Weight bearing exercises such as low-impact aerobics, walking, running, lifting weights, tennis or step aerobics help bones.
Bone loss can increase if a person's diet is low in calcium. Calcium slows the rate of bone loss. If the amount of calcium in the bloodstream is low it will be taken from the bones to supply the rest of the body. The National Institutes of Health suggest the following daily calcium intakes:
These are the requirements for daily ELEMENTAL calcium. It is very important to take a calcium supplement or vitamin that it has in it the amount of ELEMENTAL calcium needed every day. Some labels can be confusing. Individuals should check with a doctor to select the most appropriate product.
- children ages 1 to 10: at least 800 mg
- young people (11-24 yrs): 1200-1500 mg
- ages 25 to 50: 1000 mg (if ovaries are present)
- ages 25 to 50: 1500 mg (if ovaries have been removed, no HRT)
- over age 50: 1500 mg (not taking HRT)
- over age 50: 1000 mg (taking HRT)
- All women >65 yrs: 1500 mg
- pregnant or nursing: 1200 mg
The body can only absorb 350-500mg of elemental calcium at one time. Supplements should be taken in two doses (morning and evening with meals).
Good sources of calcium are:
Calcium cannot be absorbed without vitamin D. This important vitamin may be obtained from fortified milk, eggs, liver, or vitamin supplements, or by spending 15 minutes in the sun 2-3 times a week. Adequate sun exposure normally occurs with routine daily activities in the Australian climate.
- dairy products such as milk and cheese
- green leafy vegetables such as spinach
- nuts, especially almonds and sesame seeds
- seafood including scallops and prawns
Hormone replacement therapy (HRT) can help prevent bone loss. The risk of hip, vertebral and wrist fractures are about 30-50% lower in women taking HRT.
Taking oral contraceptives, or birth control pills, during the reproductive years can also slow the rate of bone loss.
How is the disease diagnosed?
Osteoporosis may be discovered in an x-ray taken for some other problem. X-rays should not be used as the only test. Other tests are more sensitive and reliable. These include:
At this time, the most commonly used and reliable test is the DEXA scan.
- DEXA scans, which show bone loss in the hip and spine
- blood bone markers, which show loss of collagen protein in the bone
- tests revealing high urine calcium excretion
- tests for serum osteocalcin, which is a marker of bone formation
- spinal x-rays, which may show vertebral compression fractures of the spine
What are the long-term effects of the disease?
If untreated, osteoporosis can lead to fractures that may result in personal disability. Fifty percent (50%) of women after a hip fracture will lose their independence. They are unable to walk without help. Many patients may need to go into a nursing home. Chronic back pain due to fractures of the spine may prevent some physical activities and affect normal sleeping.
What are the risks to others?
Osteoporosis is not contagious; there are no risks to others.
What are the treatments for the disease?
Treatment cannot eliminate osteoporosis. Medications can slow the rate of bone loss and weakening, and may build bone in some cases. Examples of these medications include:
What are the side effects of the treatments?
- oesterified oestrogens
- conjugated oestrogens
Side effects of treatment depend upon the treatment used. Some drugs cause stomach cramps, flatulence, constipation, nausea, breast tenderness, vaginal bleeding, headaches, heartburn, hot flushes or leg cramps.
What happens after treatment for the disease?
The home should be made safe to prevent accidents. Ways to increase safety include:
How is the disease monitored?
- having safe, well-lit, and uncluttered areas, to prevent falls
- using no throw rugs on floors
- taking care with icy, wet or slippery surfaces
- using non-skid mats in the shower and bathtub
- having comfortable shoes with non-slippery soles
- using a cane if needed
- not lifting heavy objects
- using proper back support and lifting methods
Women on HRT should have 2nd yearly PAP smears, breast and pelvic examinations and mammograms. Repeat bone mineral density scans may be performed 2nd yearly to see the effect of treatment on bone density. Sometimes urine tests may be done to look at bone markers every 3 months during the initial 6 to 12 months of beginning a new treatment.
Author: Eva Martin, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Potential conflict of interest information for reviewers available on request