Prevalence of Melanocytic Nevi and Freckles in Young Israeli Males

The role of host and environmental factors in the pathogenesis of multiple melanocytic nevi, atypical nevi, and freckles was studied in 1989 in a random sample of 3,040 Israeli males aged 17 years. Multiple melanocytic nevi were significantly associated with family history of melanoma or multiple melanocytic nevi (odds ratio (OR)=15.0), fair or lightly pigmented skin color (OR=2.7 and 2.3, respectively), and affiliation to the high or heterogenous melanoma risk group, determined by the incidence rates of melanoma in Jewish migrants from corresponding origin (OR=3.1 and 2.1, respectively). An environment-related effect may account for the increased multiple melanocytic nevi risk among second- (OR=8.2) compared with first-generation, native-born recruits (OR=3.0) from the high melanoma risk group whose families had been living in Israel the longest. Atypical nevi were associated with fair (OR=6.1) and lightly pigmented (OR=3.5) skin color, high and moderate sunburn susceptibility (OR=4.7 and 2.5, respectively), and family history of melanoma or multiple melanocytic nevi (OR=4.7) Freckles were significantly associated with sun-sensitive phenotype, family history of melanoma or multiple melanocytic nevi (OR=1.5), Conservative (OR=1.9) or nonreligious status (OR=1.9), and high (OR=2.4) or heterogenous melanoma risk groups (OR=1.8). These findings indicate that environmental factors may modify the occurrence of multiple melanocytic nevi and freckles in genetically susceptible ethnic groups. Am J Epidemiol 1997;146:78–86.