Osteoporosis is a condition characterized by the loss of the normal density of bone, resulting in fragile bone. Osteoporosis leads to literally abnormally porous bone that is more compressible like a sponge, than dense like a brick. This disorder of the skeleton weakens the bone causing an increase in the risk for breaking bones (bone fracture).
- The osteoporosis condition can be present without any symptoms for decades, because osteoporosis doesn’t cause symptoms unless bone fractures. Some osteoporosis fractures may escape detection until years later. Therefore, patients may not be aware of their osteoporosis until they suffer a painful fracture. Then the symptoms are related to the location of the fractures.
- Fractures of the spine (vertebra) can cause severe “band-like” pain that radiates around from the back to the side of the body. Over the years, repeated spine fractures can cause chronic lower back pain as well as loss of height or curving of the spine, which gives the individual a hunched-back appearance of the upper back, often called a “dowager hump.”
- A fracture that occurs during the course of normal activity is called a minimal trauma fracture or stress fracture. For example, some patients with osteoporosis develop stress fractures of the feet while walking or stepping off a curb.
- Hip fractures typically occur as a result of a fall. With osteoporosis, hip fractures can occur as a result of trivial accidents. Hip fractures may also be difficult to heal after surgical repair because of poor bone quality.
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
- A routine x-ray can reveal osteoporosis of the bone, which appears much thinner and lighter than normal bones. Unfortunately, by the time x-rays can detect osteoporosis, at least 30% of the bone has already been lost. In addition, x-rays are not accurate indicators of bone density. The appearance of the bone on x-ray is often affected by variations in the degree of exposure of the x-ray film.
- A dual energy x-ray absorptiometry scan (DXA, formerly known as DEXA) for diagnosing osteoporosis. DXA measures bone density in the hip and the spine. The test takes only 5 to 15 minutes to perform, uses very little radiation (less than one tenth to one hundredth the amount used on a standard chest x-ray), and is quite precise.
- The bone density of the patient is then compared to the average peak bone density of young adults of same sex and race. This score is called the “T score,” and it expresses the bone density in terms of the number of standard deviations (SD) below peak young adult bone mass.
- Osteoporosis is defined as bone density T score of –2.5 SD or below.
- Osteopenia (between normal and osteoporosis) is defined as bone density T score between –1 and –2.5 SD.
Bone density testing
There are several groups of people who should consider DXA testing:
- All postmenopausal women below age 65 who have risk factors for osteoporosis;
- All women aged 65 and older;
- Postmenopausal women with fractures, although this is not mandatory because treatment may well be started regardless of bone density;