The medical establishment has long advised people to stay out of the sun. Findings published today in the Journal of the American Medical Association suggest that people may not be heeding the message. According to the report, the incidence of some types of skin cancer is increasing in people under the age of 40.

A team of researchers led by Leslie J. Christenson of the Mayo Clinic in Rochester, Minn., analyzed medical records of patients under the age of 40 in the state's Olmsted County between 1976 and 2003. Specifically, they tracked the number of people afflicted with so-called nonmelanoma skin cancers, which include squamous cell carcinoma (SCC), as well as basal cell carcinoma (BCC), the most common form of skin cancer in the U.S. Over the study period, 485 patients were diagnosed with skin cancer. When the researchers controlled rates for age and sex, they found that between 1976 and 1979, the rate for BCC in women was 13.4 in 100,000. By 2000 to 2003, however, the occurrence had increased to 31.6. The rise for men was less dramatic, increasing from 22.9 in the 1970s to 26.7 after 2000.

BCC and SCC typically occur in people over the age of 50 and studies have shown that the number sufferers in that age group is increasing rapidly. The fact that younger people are being affected more frequently as well, the authors note, could lead to a huge surge in the number of cases as the population ages. "Our results," they conclude, "also emphasize the need to focus on the prevention of skin cancer in the very young so that the increasing incidence of a potentially preventable cancer can be halted."