NEVI IN SCHOOLCHILDREN IN SCOTLAND AND AUSTRALIA

To test the hypothesis that children living in subtropical and tropica l environments have more naevi than those of similar ethnicity living in temperate countries, a comparative study of melanocytic naevi in 11 1 schoolchildren from Brisbane, Australia, and 222 from Glasgow, Scotl and, was carried out. All children were aged 13-15 years, of European ancestry, and had spent most of their lives at latitudes of less than 30 degrees S (Australia) or greater than 30 degrees N (Scotland). Usin g an identical protocol, all naevi of 2 mm or more in diameter occurri ng on the right arm were counted by either a highly experienced resear ch nurse in Brisbane, or a dermatologist in Glasgow. Hair and eye colo ur, and facial freckling, were assessed by the examiner, and axillary skin colour of children in both cities was measured using the same ref lectance spectrophotometer. Children in Brisbane had significantly mor e naevi than those in Glasgow (P < 0.05), after adjusting for complexi on variables. The difference in the geometric mean number of naevi on the arm was much greater among boys (7.7 vs. 4.4, in Brisbane and Glas gow, respectively) than among girls (7.3 vs. 6.7). This has parallels with the sex differences in melanoma at later ages in the two countrie s. Besides country of residence, freckles and innate skin colour were the most significant predictors of large numbers of naevi, whereas red hair had a significant protective effect. Overall, these data on prev alence of naevi in children from contrasting environments provide some evidence in support of the theory that naevus development is related to the level of sun exposure in childhood and adolescence.