Site-specific melanocytic naevus counts as predictors of whole body naevi

Counts of melanocytic naevi of 2 mm or greater diameter on all body sites were conducted in 197 Caucasian adults in Scotland. Mean naevus numbers were greater in young than in older adults, and in females than in males. Naevus counts on the upper limbs, lower limbs, and trunk were strongly and significantly correlated with each other and with whole body counts. Thus, where whole body counts are impractical, counting naevi at any of these individual sites should provide a satisfactory method for studying naevus distribution in large populations. The rapid rise in the incidence and mortality of malignant melanoma over recent years has led to increased interest in the epidemiology of malignant melanoma and especially its relationship to melanocytic naevi. Several recent case-control studies have shown that naevus counts are a strong risk factor for melanoma,1–4 but relatively little is known about the distribution of and the risk factors for naevi. There have been few studies of whole body naevus counts in populations; such counts are time consuming and can be difficult to conduct in non-hospitalized patients. In the present study we have examined the relationship between naevus numbers at different sites, and also between site-specific naevus counts and whole-body counts, in a Caucasian population in Scotland.