Exposure to the sun and sunbeds and the risk of cutaneous melanoma in the UK: a case-control study.

Migration, latitude and case-control studies have clearly established a link between melanoma and sun exposure. This case-control study of melanoma was set up to examine the role of sun exposure and sunbeds in the pathogenesis of melanoma in the United Kingdom (UK), a country with low levels of ultraviolet radiation. The study included 413 cases and 416 controls. More than 10 severe sunburns compared with less than 10 sunburns was associated with an Odds Ratio (OR) of 1.98 (95% Confidence Interval (CI) 1.02-3.86) (P=0.04) when adjusted for age, gender and skin type. Sunburns before the age of 15 years were not associated with melanoma once adjustments for age, gender and skin were made. 31% of women and 16% of the men had used sunbeds. Sunbed users were younger than non-users (40 years versus 51 years, P<0.0001). Ever use of sunbeds gave an adjusted OR of 1.19 (95% CI 0.84-1.68) (P=0.33). The risk of melanoma did not increase with increasing hours or years of sunbed exposure. The risk associated with sunbed use was only significant for young individuals with fair skin for whom there was a significant OR of 2.66 (95% CI 1.66-6.09) (P=0.02) after adjustment for the sun exposure variables. Outdoor occupation and residence in hot countries were not associated with an increased risk of melanoma. The only significant associations in this study were with 10 or more sunburns and the use of a sunbed in young subjects with fair skin. Sunbed use is now becoming more prevalent in Caucasian populations and the results of this study suggest that sunbed usage may moderately affect individuals with sun-sensitive skin types. However, the magnitude of melanoma risk in association with natural and artificial sun exposure is small compared with phenotypic risk factors such as skin type and naevus counts. However, it is possible that the mean lag time of 7 years between exposure to sunbed and melanoma in this study may have led to an under-estimation of the long-term melanoma risk.