Osteoporosis (cont.)
What factors determine bone strength?
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:
- 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;
- Excessive alcohol consumption;
- 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);
- Immobility, such as after a stroke, or
from any condition that interferes with walking;
- 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).
Next: How is osteoporosis diagnosed? »
- medroxyprogesterone, Provera, Depo-Provera, Depo-Sub Q Provera 104 - Explains the medication medroxyprogesterone (Provera, Cycrin, Depo-Provera, Deop-Sub Q Provera 104), a drug used used to treat abnormal uterine bleeding, contraception, and for treating endometrial or renal cancer.
- Bone Density Scan - Get information on bone density scan for osteoporosis and osteopenia risk. Learn about bone mineral density, how the screening is done and get an explanation of test results.
- Hyperthyroidism - Learn about hyperthyroidism (overactive thyroid gland) symptoms such as irritability, tachycardia, heat intolerance, increased sweating, weight gain, and more, as well as the causes, diagnosis, and treatment of hyperthyroidism.
Latest Medical News