Factors associated with the prevalence of atypical nevus in a Mediterranean pigmented skin lesion clinic.

Atypical melanocytic nevi constitute central risk factor and are precursor lesions for cutaneous melanoma. Data regarding factors associated with their prevalence are mainly derived from fair-skinned populations, whereas little is known regarding their epidemiological associations in darker-skinned, chronically sun-exposed populations. The aim of this study was to identify risk factors for the occurrence of at least one atypical nevus on Crete, the southernmost island of Greece. This hospital-based case-control study included 143 patients and 189 controls with at least one atypical nevus presented at the pigmented skin lesion clinic of the University of Crete. All participants were interviewed and underwent complete skin examination by the same two experienced dermatologists. Multivariate logistic regression analysis was used to adjust for potential confounders. In the multivariate analysis, common melanocytic nevi [odds ratio (OR): of 2.2, 7.5, and 58.9 for the presence of 11-25, 26-100, and >100 common nevi, respectively] and recreational sun exposure (OR: 4.4) increased significantly the risk of the presence of atypical nevus. A decreased risk for atypical nevi was related to an increasing age (OR: 0.96/age), and professional sun exposure (OR: 0.5). Intermittent, recreational sun exposure is mainly associated with the prevalence of atypical nevi in our sample and this effect does not depend on skin phototype. Promotion of sun protection, especially in patients with high numbers of common nevi, might serve as a measure to prevent the development of atypical nevi.