Spending vacations at the beach during childhood may increase the risk of the deadly skin cancer melanoma later in life, according to a study published Tuesday.

Researchers examined 681 white children born in 1998 who were lifetime residents of Colorado and conducted exams on the children when they were seven years old to identify nevi -- commonly known of moles -- which are a risk factor for developing melanoma.

The study found that each vacation at the shore one or more years prior to the exam was linked to a five percent increase in nevi that were less than two millimeters (.08 inches) large.

"Parents of young children need to be cautious about taking their kids on vacations that are going to be sun-intensive at waterside locations, where people are outside for whole days at a time in skin-exposing swimsuits," said Lori Crane, chair of the Department of Community and Behavioral Health at the Colorado School of Public Health.

"We recommend that, for young children, parents keep the kids involved in indoor activities from 10:00 am to 4:00 pm to decrease risk, or if they are to be outside, that they wear shirts with sleeves."

Crane, the study's lead author, said parents often mistakenly believe that sunscreen prevents skin cancer risks. But children often stay out in the sun longer, which increases their risk, she added.

"Daily sun exposure at home did not seem to be related to the number of moles, while waterside vacations were. Vacations may impart some unique risk for melanoma," she said.

The researchers found that young boys were 19 percent more likely to develop nevi than young girls, which Crane said "may be due to an increased likelihood among boys to want to stay outdoors."

Income was also observed to be a factor, with higher income families more at risk of developing nevi because they were more likely to take vacations at the shore.

More than 62,000 Americans are diagnosed with melanoma every year and more than 8,000 die, the study said.

(Agencies via China Daily February 5, 2009)