Studies also suggest that estrogen reduces the rate of vertebral fractures. Even when started as late as 6 years after menopause, estrogen prevents further loss of bone mass but does not restore it to premenopausal levels. The lowest effective dose for prevention and treatment of osteoporosis should be utilized. Women are at higher risk than men because they have less bone mass, and for several years following natural or induced menopause, the rate of bone mass decline is accelerated. Early menopause is one of the strongest predictors for the development of osteoporosis.
White women are at higher risk than black women, and white men are at higher risk than black men.
Women who are underweight also have osteoporosis more often than overweight women. Cigarette smoking may be an additional factor in increasing risk. Calcium deficiency has been implicated in the pathogenesis of this disease. Immobilization and prolonged bed rest produce rapid bone loss, while weight-bearing exercise has been shown both to reduce bone loss and to increase bone mass. The optimal type and amount of physical activity that would prevent osteoporosis have not been established.