Skin characteristics and risk of superficial spreading and nodular melanoma (United States)

Objective: To assess the risk for melanoma associated with moles and pigmentary characteristics. Methods: Representative melanoma cases (773) among non-Hispanic white residents under age 65 occurring between 1 June 1978 and 1 December 1983 in Los Angeles County were compared to controls (752) matched to cases by age, sex, race and neighborhood of residence. Factors considered include hair, eye, and skin color; numbers of freckles and moles; and propensity to burn and tan obtained during an in-person interview. Results: Five hundred and fifty-one cases were classified as superficial spreading melanoma (SSM) and 110 as nodular melanoma (NM). For SSM, the important risk determinants were hair and skin color, freckling, and mole prevalence. Light skin and more freckles were found to be more highly associated with SSM for younger compared to older subjects, whereas the associations between SSM and both hair color and moles remained independent of age. NM showed patterns of risk similar to SSM with the exception of skin color. NM showed no evidence of increasing risk with lighter skin, as compared to the strong association seen for SSM. Conclusion: Hair and skin color, freckling and, especially, numbers and size of moles are important determinants of melanoma risk.