Association of cutaneous malignant melanoma with intermittent exposure to ultraviolet radiation: results of a case-control study in Ontario, Canada.

BACKGROUND: Although solar radiation is well established as a risk factor for melanoma, it is less clear how the pattern and timing of exposure to ultraviolet (UV) radiation might be important. The particular objective of this study was to evaluate the association of melanoma risk with various measures of intermittent and chronic exposures to UV radiation, and to assess how these exposures interact with other risk factors such as skin type.