The density of melanocytic nevi correlates with constitutional variables and history of sunburns: a prevalence study among Italian schoolchildren

Abstract

In several studies from northern Europe, north America and Australia, melanocytic nevi are correlated with pigmentary traits and with intense sun exposure in a way similar to malignant melanoma. However, it is unclear if these data can be extrapolated to populations in other geographic locations and with different prevalent phenotypes. Our study was conducted among schoolchildren aged 13-14 years in 16 Italian cities. The parents of 3,127 children of a total of 3,160 (99%) consented to our study. A structured questionnaire was used to collect information about sun exposure and lifetime history of sunburns. Children were also examined by trained dermatologists to assess pigmentary traits and to make a count of melanocytic nevi. The median nevus density was higher among boys than girls. Areas that are usually chronically exposed to the sun exhibited a higher density of nevi compared to intermittently and rarely exposed areas. A higher density of nevi was found in children with lighter skin, blond hair and blue eyes. Red-haired children had a remarkably lower nevus density compared to the other color categories. The density of nevi increased with an increased number of reported episodes of sunburns. The results concerning nevi >/=6 mm in diameter paralleled those obtained for the total nevus density. However, at variance with total nevus density, a significant relation was also observed between larger nevi and freckling. Our study confirms that, in Italian schoolchildren, there is a relation between pigmentary traits, history of sunburns and the density of melanocytic nevi. Melanocytic nevi and malignant melanoma share a similar risk factor profile.