Osteoporosis Symptoms, Treatment, Causes, Prevention, Risk Factors and Diagnosis by MedicineNet.com

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Osteoporosis (cont.)

What factors determine bone strength?

Bone mass (bone density) is determined by the amount of bone present in the skeletal structure. Generally, the higher the bone density, the stronger the bones. Bone density is greatly influenced by genetic factors, which in turn are sometimes modified by environmental factors and medications. For example, men have a higher bone density than women, and African Americans have a higher bone density than Caucasian or Asian Americans.

Normally, bone density accumulates during childhood and reaches a peak by around age 25. Bone density then is maintained for about 10 years. After age 35, both men and women will normally lose 0.3%-0.5% of their bone density per year as part of the aging process.

Estrogen is important in maintaining bone density in women. When estrogen levels drop after menopause, loss of bone density accelerates. During the first five to 10 years after menopause, women can suffer up to 2%-4% loss of bone density per year! This can result in the loss of up to 25%-30% of their bone density during that time period. Accelerated bone loss after menopause is a major cause of osteoporosis in women.

What are the risk factors and causes of osteoporosis?

The following are factors that will increase the risk of developing osteoporosis:

Female gender

Caucasian or Asian race

Thin and small body frame

Family history of osteoporosis (for example, having a mother with an osteoporotic hip fracture doubles your risk of hip fracture)

Personal history of fracture as an adult

Cigarette smoking

Excessive alcohol consumption

Lack of exercise
Diet low in calcium

Poor nutrition and poor general health

Malabsorption (nutrients are not properly absorbed from the gastrointestinal system) from conditions such as celiac sprue

Low estrogen levels in women (such as occur in menopause or with early surgical removal of both ovaries)

Low testosterone levels in men (hypogonadism)
Chemotherapy that can cause early menopause due to its toxic effects on the ovaries

Amenorrhea (loss of the menstrual period) in young women associated with low estrogen and osteoporosis; amenorrhea can occur in women who undergo extremely vigorous exercise training and in women with very low body fat, for example, women with anorexia nervosa

Chronic inflammation, due to chronic diseases such as rheumatoid arthritis or liver diseases

Immobility, such as after a stroke, or from any condition that interferes with walking

Hyperthyroidism, a condition wherein too much thyroid hormone is produced by the thyroid gland (as in Grave's disease) or is ingested as thyroid hormone medication

Hyperparathyroidism is a disease wherein there is excessive parathyroid hormone production by the parathyroid gland, a small gland located near or within the thyroid gland. Normally, parathyroid hormone maintains blood calcium levels by, in part, removing calcium from the bone. In untreated hyperparathyroidism, excessive parathyroid hormone causes too much calcium to be removed from the bone, which can lead to osteoporosis.

When vitamin D is lacking, the body cannot absorb adequate amounts of calcium from the diet to prevent osteoporosis. Vitamin D deficiency can result from lack of intestinal absorption of the vitamin such as occurs in celiac sprue and primary biliary cirrhosis.
Certain medications can cause osteoporosis. These include long-term use of heparin (a blood thinner), antiseizure medications such as phenytoin (Dilantin) and phenobarbital, and long-term use of oral corticosteroids (such as prednisone).