Incidence of cutaneous melanoma in Western Sweden, 1970-2007

The aim of this study was to describe the increasing incidence of cutaneous malignant melanoma (CMM) in Western Sweden during the period 1970-2007. A secondary aim was to show a geographical variation in incidence between coastal and inland areas, considering the effects of the local average duration of sunshine, and the sun exposure-related behavior in the populations. The Swedish Cancer Registry provided data on invasive melanomas during 1970-2007. Meteorological maps showed the annual average duration of sunshine during 1961-1990. A survey from 2007 with 2871 participants, carried out by the National Board of Health and Welfare, provided data on self-reported sun exposure. During the period studied, the age-standardized incidence for men in Western Sweden more than quadrupled to 31.1/100 000 inhabitants, whereas it tripled for women to 27.1/100 000. Coastal areas, including Gothenburg city, had a high average duration of sunshine (1701-1900 h of sun/year), whereas inland areas had lower average duration of sunshine (≤1700 h). The incidence of CMM was higher in coastal areas and in Gothenburg city, compared with inland areas. This may be linked to ultraviolet radiation, a consequence of the higher average duration of sunshine. The sun exposure survey showed additional factors, which possibly led to the increased incidence, for example high sun exposure on holidays abroad. The alarming increase in the incidence of CMM in Western Sweden, during the period 1970-2007, shows the need for additional primary preventive measures, for example sun protection programs targeted at populations in this area.