Why does the diease Osteoporosis most common in older women ?

As the body ages, the bones and muscles naturally weaken. Osteoporosis occurs when there is not enough calcium in the body for the individual's use. In efforts to function, the body takes from its calcium deposits. Bones are considered a bank of calcium. When the bones weaken, they become more brittle naturally, however if the body is not being supplied with enough calcium, the body takes from the bones leaving these bones even weaker than before. This occurs in women post menopausal because there is a connection to decrease in bone density after menopause occurs in women. This makes the woman then more prone to develop osteoporosis. The best prevention is to ensure enough calcium in the diet throughout life as well as exercise. Exercise helps the bones to become stronger and therefore there is a bigger "bone bank" to take from when the body needs the calcium.

It's mainly due to the many different hormones in a female body as compared with the male body.
It is because they lack calcium in their body.
It's primarily related to hormonal changes that occur at or around menopause and how this effects bone density. Calcium is commonly recommended for this, but it's important to balance this with magnesium as well as vitamins such as Vit. D. There are some good nutritional formulas out there that include all these necessary components together.
Women have small bone density than men.
There's several reasons why one develops Osteoporosis. However, if you did not reach your maximum amount of bone density in your youth, you are more likely to develop Osteoporosis. Poor diet, lacking of calcium, phosphorous and Vitamin D and lack of exercise contributes to thinning bones. Weak bones can also be inherited from your parents.
As women and men age, they lose bone mass more rapidly. Older women lose bone mass most often when undergoing menopause because they produce less of the female hormone estrogen which is necessary to keep the bones strong. Also, when older women have surgery to remove their ovaries, they lose the function to produce estrogren. Smoking also increases bone loss.
Osteoporosis is considered a silent disease because most people don't know they have it. There is no cure for it but there are preventive methods such as HRT (hormone replacement therapy).
http://www.webmd.com/osteoporosis/tc/ost...
http://www.nof.org/osteoporosis/diseasef...