Frequency of moles in a defined population.

The occurrence of moles was studied in a community survey of 872 adults, using criteria that allowed comparison with two earlier surveys. Men and women had similar numbers of moles-on average, 15 moles of diameter 2 mm or greater, and 39 moles of all sizes. The frequency of moles declined with age and varied according to body site. Comparison of the findings with those of previous surveys-in New York in about 1950 and in Sydney in about 1970-suggested that the frequency of moles has increased as malignant melanoma has become more common. Little is known about the epidemiology of moles, which may hold the key to the explanation of the rising incidence of melanoma in many countries.