Bone mass (bone density) is the amount of bone present in the skeletal structure. Generally, the higher the bone density is, the stronger are 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. 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 is then maintained for about ten years. After age 35, both men and women will normally lose 0.3% to 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, bone loss accelerates. During the first five to ten years after menopause, women can suffer up to two to four percent loss of bone density per year! This can result in the loss of up to 25 to 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 for developing osteoporosis ?
Factors that will increase the risk of developing osteoporosis are :
- Female gender;
- Caucasian or Asian race;
- Thin and small body frames;
- 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 (such as occur in menopause or with early surgical removal of both ovaries);
- Chemotherapy can cause early menopause due to its toxic effects on the ovaries;
- Amenorrhea (loss of the menstrual period) in young women also causes low estrogen and osteoporosis; Amenorrhea can occur in women who undergo extremely vigorous training and in women with very low body fat (example: anorexia nervosa);
- Chronic inflammation, due to diseases (such as rheumatoid arthritis and chronic 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 caused by taking too much thyroid hormone medication;
- Hyperparathyroidism, a disease wherein there is excessive parathyroid hormone production by the parathyroid gland (a small gland located near the thyroid gland). Normally, the 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;
- Vitamin D deficiency. Vitamin D helps the body absorb calcium. When vitamin D is lacking, the body cannot absorb adequate amounts of calcium 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), anti-seizure medications phenytoin (Dilantin) and phenobarbital, and long term use of oral corticosteroids (such as Prednisone).
Sources medicinet.com
