autoimmune condition in which the cells that make pigment (melanocytes) are
destroyed, resulting in patches of hair and skin that become white.
There may also be a link with decreased bone mineral density in
postmenopausal women, which is a risk factor for osteoporosis. In a study of
293 healthy postmenopausal women, those who had experienced premature
graying of a majority of their hair by age 40 had decreased bone density
throughout their bones compared with comparable women who did not have
premature graying.