AURORA, Colo. – A new study led by researchers at the Colorado School of Public Health at the University of Colorado Denver has found very light-skinned children who tan appear to develop more moles on the skin than children who do not tan. The presence of these moles is the strongest risk factor for melanoma development.
Cutaneous melanoma ranks sixth in incidence of all cancers among men and women in the United States and the findings of the study are concerning. The authors cite studies that found much of the preventable risk for melanoma is established in childhood, and developing habits around sun exposure and protection is particularly important early on in life. In Colorado, the higher elevation combined with more than 300 days of sunshine a year leads residents to have increased exposure to UV rays, resulting in a melanoma incidence rate that is approximately 30 percent higher than the national average.
“The number and size of nevi, also known as moles, are often used for determining the risk of developing melanoma,” said Lori Crane, PhD, chair of the department of Community & Behavioral Health at the Colorado School of Public Health and principal investigator on the study. “The risk factors for melanoma development and higher nevus counts include lighter hair color, eye color and skin color, greater UV exposure, higher frequency and severity of sunburns, and freckling.”
Although previous studies on tanning exposure and nevus development in the white population have been conducted, none have focused on the relationship between tanning and nevi in those with the very lightest skin.
For the study, the researchers conducted skin exams in 2004, 2005 and 2006 to determine full-body counts of nevi in 131 very light-skinned white children without red hair and 444 darker-skinned white children without red hair, all of whom were all born in Colorado in 1998. Redheads were excluded because previous studies have shown that individuals with red hair have fewer moles than all other hair colors in the white population.
Among very light-skinned white children, the average number of nevi for minimally tanned children were 14.8 at age 6; 18.8 at 7 years and 22.3 at age 8. For tanned children, those numbers increased significantly to 21.2 at 6 years; 27.9 at age 7 and 31.9 at age 8.
“Differences in counts between untanned and tanned children were statistically significant at all ages,” said Crane. “Across the board, these findings suggest that UV tanning promotes nevus development in non-redhead children with the lightest skin pigmentation. Our results suggest that tanning avoidance should be considered as a measure for the reduction of melanoma risk in very light-skinned children—and this is not just a call for using more sunscreen but a move to avoid the sun’s harmful rays during peak of the day by staying inside or wearing protective clothing.”
This study is published in the September issue of Archives of Dermatology, one of the Journal of the American Medical Association (JAMA)/Archives journals and was supported in part by a grant from the National Cancer Institute.
The new Colorado School of Public Health is the first and only school of public health in the Rocky Mountain Region, attracting top tier faculty and students from across the country, and providing a vital contribution towards ensuring our region’s health and well-being. Collaboratively formed by the University of Colorado Denver, Colorado State University, and the University of Northern Colorado, the Colorado School of Public Health provides training, innovative research and community service to actively address public health issues, including chronic disease, access to health care, environmental threats, emerging infectious diseases, and costly injuries.