Multicenter case-control study of risk factors for cutaneous melanoma in Valencia, Spain.

INTRODUCTION It is important to identify subgroups within the general population that have an elevated risk of developing cutaneous melanoma because preventive and early-detection measures are useful in this setting. The findings of most studies that have evaluated risk factors for cutaneous melanoma are of limited application in Spain because the populations studied have different pigmentary traits and are subject to different environmental factors. OBJECTIVE To identify the phenotypic characteristics and amount of exposure to sunlight that constitute risk factors for cutaneous melanoma in the population of the Autonomous Community of Valencia, Spain. METHODS We performed a multicenter observational case-control study. In total, the study included 242 patients with melanoma undergoing treatment in 5 hospitals and 173 controls enrolled from among the companions of the patients between January 2007 and June 2008. The information was collected by means of a standardized, validated questionnaire. The odds ratio (OR) was calculated for each variable and adjusted using a multiple logistic regression model. RESULTS The risk factors found to be statistically significant were skin phototypes I and II, blond or red hair, light eye color, abundant melanocytic nevi, and a personal history of actinic keratosis or nonmelanoma skin cancer. After the multivariate analysis, only blond or red hair (OR=1.9), multiple melanocytic nevi (OR=3.1), skin phototypes i and ii (OR=2.1), and a personal history of actinic keratosis (OR=3.5) or nonmelanoma skin cancer (OR=8.1) maintained significance in the model as independent predictive variables for melanoma. CONCLUSIONS Our study supports the importance of certain factors that indicate genetic predisposition (hair color and skin phototype) and environmental factors associated with exposure to sunlight. Patients with multiple acquired melanocytic nevi and patients with markers of chronic skin sun damage (actinic keratosis and nonmelanoma cancer) presented a significant increase in risk.