Increasing Numbers of Sunburns May Trump Childhood Exposure in Melanomas

Melanoma prevention efforts for years have focused largely on the risks associated with being seriously sunburned during childhood. Results of a recently published meta-analysis show an increased risk of melanoma with increasing number of sunburns throughout all life-periods.

“Experts have been stating that childhood sunburns are what is important in assessing melanoma risk,” says Leslie K. Dennis, PhD, associate professor of epidemiology in the Department of Public Health at the University of Iowa in Iowa City and lead author of the article. “We just wanted to know if that is really what the literature says.”

The authors reviewed over 1,300 article titles. After evaluating 270 articles in detail, the odds ratios (OR) from 51 study populations were entered into the analysis. Of these, 26 studies reported results from dose-response models.

“Looking at the available data, we found that every time period of life had an increased risk of melanoma,” says Dennis. “The problem, however, was that, ‘Have you ever been sunburned?’ is not really a good measure.”

The researchers then specifically analyzed those studies where dose-response data was reported across different time periods. Only 26 studies were identified. “That kind of surprised me,” Dennis says. “We have been saying childhood sunburns are the most important, apparently based on very few studies. We have found 27 studies reporting ‘ever being sunburned’ during childhood and only 10 studies of dose-response during childhood upon which to base that generalization.”

When the results of studies were analyzed by decade of life, they found large ORs for adult and lifetime exposure. This indicates that it is the number of sunburns, not when they are received, that is the important variable in assessing melanoma risk.

Dr. Dennis stresses that she is not suggesting that childhood sunburns do not play an important role in the development of melanoma later in life. Rather, she thinks that prevention efforts should change their focus to the importance of sunburn prevention throughout life.

“In the past, when we were stressing the importance of avoiding childhood sunburns, some adults may have taken the view that since they could not change what happened when they were kids, they could do whatever they wanted now,” she says. “But our analysis indicates that all sunburns matter, whether they happen in childhood, adolescence, or adulthood. We need to stress dose more and age less.”

Alan Geller MPH, RN, is associate professor of dermatology at the Boston University School of Medicine. He was not involved in the study.

“For many years, organizations that have called for the public to protect themselves from the sun have concentrated almost exclusively on the need for parents and caregivers to protect their young children from excessive sun exposure and sunburns,” Geller says. “The current study surely upholds this recommendation but provides the most conclusive evidence to date of the need for vigilant sun protection to prevent sunburning from early formative years throughout the lifespan.”

He feels that the validity of the study’s findings is enhanced by the excellent study design and the inclusion of all prior studies on the relationship between sunburns and melanoma in the analysis.

“The bottom line message is that increasing number of sunburns accentuates the risk of melanoma no matter what age they are received,” Geller says. “Prevention efforts must be accelerated in all outdoor areas where persons of all ages congregate, whether it is the outdoor pool, ball field, the golf course, or the garden.”

Dennis LK, et al. Sunburns and risk of cutaneous melanoma: does age matter? A comprehensive meta-analysis. Ann Epidemiol. 2008 Aug;18:614-27.

Kurt Ullman is a freelance health and medical writer based out of Indianapolis.