International journal of cancer. Journal international du cancer
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In a hospital-based case-control study of ovarian cancer conducted in Athens (1989-1991), 189 women with histologically confirmed common malignant epithelial tumors of the ovary were compared with 200 hospital visitor controls. All interviews were conducted by personal interview in the 2 participating hospitals and the data were analyzed by modelling through logistic regression, controlling for demographic and reproductive variables. ⋯ There was a statistically significant (p for trend 0.007) and a dose-dependent association between hair dyeing and risk of ovarian cancer. Compared to never-users, women dyeing their hair up to 4 times per year had a relative risk of 1.74 (0.91 to 3.32) whereas those dyeing their hair 5 or more times per year had a relative risk of 2.16 (1.19 to 3.89).