Ultraviolet light exposure, pigmentary traits and the development of melanocytic naevi and cutaneous melanoma. A case-control study of the German Central Malignant Melanoma Registry.

The present study firstly aimed at understanding the relationship between sun exposure, pigmentary traits and the history of sunburns. Secondly, the significance of UV-exposure for cutaneous melanoma and for melanocytic naevi was investigated. The case-controlled study comprised 513 patients with primary cutaneous melanoma and 498 controls matched by age and gender. Multivariate logistic regression analysis was used to study melanoma risk factors. The number of common melanocytic naevi was associated with age, gender, the history of sunburns and UV-exposure during holidays (odds-ratio = 1.9; 95% confidence interval = [1.1, 3.41) for 3 weeks or more. The number of atypical melanocytic naevi was significantly related to age, gender, pigmentary traits, the history of sunburns and UV-exposure during holidays (odds- ratio=3.5 ; 95% confidence interval=[1.4, 9.0]) for 2 months or more. The results of the present study showed that both the history of sunburn and intensive sun exposure during holidays were important for the development of melanocytic naevi and, therefore, indirectly for cutaneous melanoma. In addition, a particular type of pigmentation was found to be related to atypical melanocytic naevi.