To maintain bone density, the body requires an adequate supply of calcium and other minerals and must produce the proper amounts of several hormones, such as parathyroid hormone, growth hormone, calcitonin, estrogen in women, and testosterone in men. Also, an adequate supply of vitamin D is needed to absorb calcium from food and incorporate it into bones. Bones progressively increase in density until a maximum density is reached, around age 30. After that, bones slowly decrease in density. If the body isn't able to regulate the mineral content of bones, they become less dense and more fragile, resulting in osteoporosis.
Types There are several different types of osteoporosis.
Postmenopausal osteoporosis is caused by a lack of estrogen, the main female hormone, which helps regulate the incorporation of calcium into bone in women. Usually, symptoms develop in women between ages 51 and 75, but they can begin earlier or later. Not all women are at equal risk of developing postmenopausal osteoporosis. For example, white and Oriental women are more prone to the condition than black women. Senile osteoporosis probably results from age-related calcium deficiency and an imbalance between the rate of bone breakdown and new bone formation.