Wealthier, more educated women seem to be at greatest risk of melanoma, rates of which have more than doubled among young white women in the past three decades, the New York Times reports. The reason isn’t known, but according to a new study, it could be due to the fact that wealthy, educated women are spending more leisure time outside than their lesser-heeled counterparts. In the study, researchers at the Cancer Prevention Institute of California looked at 3,842 cases of melanoma in 3,800 white women under 40 who were diagnosed between 1988 and 1992, and 1998 and 2002. They compared this with census data and ultraviolet radiation exposure measures. Melanoma rates went up significantly during study periods only among higher income women, with highest income women nearly six times as likely to get a diagnosis of malignant melanoma than those in the poorest areas.