Osteoporosis is the most common bone disease occurring in 1 in 5 women and about half as many men. There are two types. Primary osteoporosis occurs as aging causes an insufficient quantity of calcium and phosphate to be delivered throughout the body. Secondary osteoporosis occurs at any age (equally in men and women) as these minerals are lost as a side effect of medications or some diseases.
In either case, if calcium and phosphate are not delivered in sufficient quantity bone tissue is not produced and, in fact, the body will reabsorb these minerals from existing bone tissue for other needs. This in turn weakens the bones and they become more susceptible to fractures such as the common hip fracture among the elderly. Another common evidence is dowager’s hump (kyphosis) or the stooped posture in the elderly. As the disease progresses the weight bearing vertebrae in the back sustain minute fractures usually going unnoticed until the cumulative effect begins to show with this common evidence of growing older.
A major cause of primary osteoporosis is hormonal imbalance in later years. The drop in estrogen in women after menopause and the drop in testosterone among men alters the way the body assimilates calcium and phosphates. Additional risks factors are being thin and short, heavy use of alcohol, tobacco, caffeine, and a family history of osteoporosis. These, coupled with a lack of exercise, increase the risk after age 50 for women and age 70 for men.
Secondary osteoporosis may come with long term use of steroids, the anticoagulant heparin, alcohol, or tobacco. Being confined or bedridden, lactose intolerance, or hyperthyroidism can also be causes.
The most common test to determine the degree of bone degeneration or the risk of fracture is the DEXA scan or DXA (dual-energy X-ray absorptiometry) scan. This is a relatively simple x-ray procedure that analyzes the density of the bone (BMD or bone mineral density) and the most common result is the T score that shows a comparison with the average young woman at age 30. This is chosen since this is the age of peak bone density in females. This number can range from a best of 1.0 to a worst of –4.0. Here is what this number means:
1.0 to – 1.0 Normal. This indicates your bone density is in the normal range of a 30 year old
– 1.0 to – 2.5 Osteopenia. This is considered osteopenia or an increased risk of fracture but not considered osteoporosis
– 2.5 to – 4.0 Osteoporosis. This is considered osteoporosis with a definite risk of fracture.
Another result that may be given is the Z score. This compares someone to the average of their own age group rather than a 30 year old. Some point out this is helpful but may be misleading because you may be good compared to your age group average but that average may have a high percentage of bone loss and fractures. They suggest for this reason it is better to set a goal based on the T score and the absolute risk of problems.
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