Ecological analysis of the relation between sunbeds and skin cancer

Background/purpose: Previous studies implicate sunbeds in skin cancer aetiology. Women use sunbeds considerably more than men and the relation between sunbed use and skin cancer formation may therefore be explored as a sex difference. This presupposes that the sunbathing habits and the distribution of sun vacations among men and women have not changed over the last decades. Methods: The incidence of new diagnosed cutaneous malignant melanoma (CMM), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) per year was provided. The numbers were grouped into sex and different age groups: 0-39, 0-44, 0-49 and 0-54 years. Linear regression analyses of time vs. incidence were performed from 1977 to 1989 and from 1990 to 2002. The slopes for men and women were compared. Data on the sunbathing habits and number of sun vacations for men and women were investigated. Results: The sunbathing habits and the distribution of sun vacations among men and women were constant from 1992 to 2002 but women used sunbeds three to four times more frequently than men. No significant difference in slopes was found in any age group for CMM or in the period 1977-1989 for BCC. However, the slopes differed significantly in almost all age groups for BCC from 1990 to 2002 (P <= 0.05). Sufficient data for SCC did not exist. Conclusions: Sunbed use was associated with BCC but not with CMM.