Increased incidence of malignant melanoma after peaks of sunspot activity.

The age-adjusted incidence-rate for malignant melanoma in the State of Connecticut has risen from 1.1 per 100 000 individuals in 1935 to 6.2 per 100 000 individuals in 1975. Superimposed on a steady rise in incidence are 3-5 year periods in which the rate of increase in incidence rises. These periods have a cycle of 8-11 years and follow times of maximum sunspot activity.