Oral contraceptive use and risk of cutaneous malignant melanoma in a case-control study of French women.

We report the results of a case-control study designed to analyze the relationship between oral contraceptive use (OC) and the risk of cutaneous malignant melonama (MM) in 240 White women under the age of 45. Five French centers participated in the study between February 1982 and January 1987 for periods of eight to 54 months, depending on the center. Cases were 91 consecutive newly diagnosed patients with histologically verified MM. Each case was matched with one or two controls on year of birth, date of interview, and treatment center. Controls were 149 patients with either malignant or nonmalignant disease who came to the center for diagnosis and treatment. Odds ratios (OR) were estimated by multivariate analyses taking into account age at menarche, sunlight exposure, and skin characteristics. No significant relation was found between the risk of MM and the total duration of OC use, age at start of use, and elapsed time since the first OC use. However, when the analysis was restricted to women aged 30-40 years, i.e., those who were able to use OC for 10 years or more, or who had started OC use 15 years or more before the diagnosis, the risk of MM increased significantly with the duration of OC use (P = 0.03). A total of more than 4,000 hours of sunlight exposure, and menarche before the age of 14 also were found to increase significantly the risk of MM (OR = 5.4, 95 percent confidence interval [CI] = 1.6-18.3; and OR = 3.6, CI = 1.0-12.5, respectively).