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TYPES OF OSTEOPOROSIS
|
Feature |
Type I |
Type II |
|
Female:male ratio |
6:1 |
2:1 |
|
Age range |
51-65 |
> 75 |
|
Type of bone affected |
Trabecular |
Cortical/trabecular |
|
Typical fracture sites |
Vertebrae, wrist |
Hip |
|
Type of bone loss |
Accelerated |
Gradual |
|
Pathophysiology |
Increased resorption |
Decreased formation |
Two different types of involutional osteoporosis have been described, although
both types are actually end-state conditions as opposed to specific diseases.9
Type I osteoporosis, or "high turnover" osteoporosis, occurs most frequently
in postmenopausal women between the ages of 51 and 65. Other features include
a diminishing amount of trabecular bone and fractures of the vertebrae and wrist.
The pathophysiologic defect in this type of osteoporosis is thought to be due
to increased bone resorption due to estrogen deficiency.
Type II osteoporosis is also sometimes referred to as "senile" osteoporosis, and occurs more often in men than type I osteoporosis, but still predominantly affects women. This category is associated with more gradual bone loss that affects cortical and trabecular bone equally, and is thought to be due to decreased bone formation. Women are probably more commonly affected with Type II osteoporosis than men, because risk for fractures accumulates over a lifetime, and women have the residual effects of menopausal bone loss.
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