The incidence of melanoma, a serious form of skin cancer, has risen sharply in Minnesota since 2005, and state health officials are urging caution about exposure to the sun -- winter and summer -- and tanning beds.

"If not found early, melanomas can spread to other parts of the body and can be deadly," said Dr. Ed Ehlinger, the state's health commissioner. "For Minnesotans, the main risk for sun exposure is in the summer, but we also want to remind people taking winter vacations that they risk serious health consequences if they don't protect their skin from ultraviolet light."

Melanoma rates rose 38 percent for females and 35 percent for males between 2005 and 2009, the Health Department said Thursday. In raw numbers, that meant 6,204 cases in the second half of the past decade, compared with 4,521 during the first half. Similar increases have been reported nationwide.

Mortality rates from melanoma, however, have been stable; 144 Minnesotans died from the disease last year.

Ehlinger said the best protection is reduced exposure to ultraviolet light -- natural and artificial.

"The idea that it is a good health move to get a 'base tan' before going on vacation is a myth," Ehlinger said. "Sunburns and exposure to the sun or tanning booths increase one's risk of cancer. ... A base tan is just more exposure that adds to your risk of developing skin cancer."

Health statisticians noted that among Minnesotans over age 55, melanoma is more common among men, perhaps because of more outdoor sports and occupations. For people between 20 and 49, however, melanoma is much more common among women, with officials speculating that it may be linked to indoor tanning.

The risk of contracting melanoma among Minnesotans is rising among all age groups. In particular, the melanoma rate for non-Hispanic white women ages 20-49 has doubled since 1995 and was twice the rate for men in this demographic in 2009, the state found.

State officials added that better detection also could be contributing to the higher rates.

Olmsted County in southeastern Minnesota, home to the Mayo Clinic, has the highest melanoma rate (49.7 cases per 100,000 population). The lowest is Koochiching County in far northeastern Minnesota (12.8 per 100,000). Twin Cities counties ranged from 20.2 to 28.1. By comparison, the state rate over the 2005-2009 span was 23.2 per 100,000.

Paul Walsh • 612-673-4482