According to Korean researchers, people with osteoporosis are much more likely to have vertigo than people with normal bone density. The study compared 209 people with benign positional vertigo with no known causes such as ear surgery or head trauma with 202 people with no history of dizziness. Patients with osteoporosis (low bone density) were three times more likely to have vertigo when compared to participants with normal bone density and those with osteopenia (the stage before osteoporosis) were two times more likely to have vertigo. 25 percent of the women with vertigo had osteoporosis, compared to 9 percent of those without vertigo, and 47 percent patients with vertigo had osteopenia, compared to 33 percent of those without vertigo. 12 percent of the men with vertigo had osteoporosis, compared to 6 percent of those without vertigo, and 40 percent with vertigo had osteopenia, compared to 27 percent of those without vertigo. Estrogen’s role in vertigo hasn't been determined.