Changes in Body-site Distribution of Common Melanocytic Naevi Among 7-year-old Swedish Children Between 2002 and 2007

Abstract

An observational population-based study conducted among 2 sets of 7-year-old children in Sweden in 2002 and 2007 revealed evidence of improved sun protection, also reflected in a significant reduction in the total number of melanocytic naevi. Based on these data-sets, the aim of the current study was to determine whether the overall reduction in naevi had impacted differently on body sites based on their main pattern of sun exposure. In 2002, median naevi counts/m2 were highest on intermittently sun-exposed sites: 13.8 (95% CI 8.0–22.7) compared with chronically sun-exposed sites: 11.0 (95% CI 0.0–20.5). In 2007, median naevi counts/m2 on intermittently sun-exposed body sites were significantly lower: 8.7 (95% CI 4.7–15.2), p<0.0001, while on chronically exposed sites median naevi counts/m2 were unaltered: 10.3 (95% CI 0.0–14.4), p=0.9313. Changes were most evident among boys. Future research can evaluate whether this shift in naevi distribution in Swedish children translates into a reduction in cutaneous melanomas on intermittently sun-exposed body sites.