Benign pigmented nevi in children. Prevalence and associated factors: the West Midlands, United Kingdom Mole Study.

BACKGROUND AND METHODS--Prevalence of benign melanocytic nevi (moles) has been shown to be a major predictor of malignant melanoma. In this study the prevalence of moles in a group of 2140 children, aged 4 to 11 years, was determined. A standard questionnaire was completed by the parents of each child and included information on environmental and life-style factors. Examination data for each child were linked to the data obtained from the questionnaire. RESULTS--Prevalence increases rapidly throughout childhood and studies of children may indicate which factors contribute to mole development. Boys had more moles than girls, as did white children when compared with other ethnic groups. Prevalence of moles increased with age in children of both sexes. Among whites, skin color had little influence on mole prevalence. The following characteristics, however, were associated with an increased prevalence of moles: a propensity to burn rather than tan, a history of sunburn, a tendency to freckle, and a life-style involving increased sun exposure. A striking positive association between prevalence of moles and number of foreign holidays in a hot climate was observed. This association was independent of a history of sunburn. CONCLUSIONS--The study supports the hypothesis that environmental factors influence the prevalence of moles in childhood.