The incidence of two types of skin cancer has nearly tripled among women under age 40, a sign that tanning is still popular among the young despite warnings about the harm it can cause, researchers said on Tuesday.

The rate of basal cell and squamous cell cancers rose to 32 per 100,000 women under 40 in 2003 from 13 per 100,000 in the late 1970s, their study said.

Basal cell and squamous cell cancers are the two most common forms of the disease and can be removed and treated more easily than the deadlier Melanoma type.

“Tan is still accepted as a sign of health and a sign of beauty and so changing that message is going to be important to accept fair skin as very healthy and beautiful,” said study author Dr. Leslie Christenson of the Mayo Clinic in Rochester, Minnesota.

The study looked at some 500 skin cancer cases in surrounding Olmsted County, Minnesota, where the population’s comprehensive health records are examined as part of the clinic’s Rochester Epidemiology Project.

Young women, especially, still use tanning beds and lie in the sun despite health warnings about cumulative skin damage from sun rays, Christenson said in a report published in the Journal of the American Medical Association.

Among men under 40, the incidence of basal cell cancers did not increase though the rate of squamous cell cancers among men did rise, the study said. Christenson said that men may not pay as much attention to their skin as women, and might not spot the tell-tale discolored bumps as often.

Basal cell cancer usually appears as a pink bump on the skin, which can be superficial or bleed and does not go away. Squamous cell cancer can also look very pink, but it is usually scaly and appears as a rough, raised bump.

In the United States, there were 800,000 new cases of basal cell and 200,000 cases of squamous cell cancers diagnosed in the year 2000.

Cases are increasing rapidly in people over age 50 as well, the report said.