And, according to the new study, a parent's mole count can help predict how many moles a child will develop, suggesting a possible genetic component associated with melanoma.
Sun exposure is the main risk factor for skin cancer, though the link is less strong for melanoma, the most rare type of skin cancer. It is known that the risk of developing melanoma goes up in relation to the number of sunburns in childhood or adolescence, according to public health experts.
In the current investigation, Dr. Tine Sander Wiecker of Eberhard-Karls-University in Tuebingen and colleagues report on their study of sun exposure and moles in 1,812 German nursery school children aged 2 to 7. The researchers also evaluated moles on the children's parents.
The number of moles on children's bodies increased with age. Half of 2-year-olds had at least three moles, while half of 7-year-olds had at least 19 moles, the authors report in the February 1 issue of the journal Cancer.
"High numbers of nevi (moles) in children were associated with the number of weeks on sunny holidays, outdoor activities at home, skin type, facial freckling, ethnicity of parents, and the number of nevi on the arms of parents," Wiecker and colleagues note.
This finding underscores the need for general sun protection in children as a means to prevent skin cancer, and not just sunburn avoidance, according to the report.
What's more, the investigators found a "strong association between nevus (mole) development in children and the number of parental moles, which most likely points to an inherited factor."
However, the number of previous sunburns was not associated with formation of moles that might later become cancerous, the study indicates.
The researchers conclude that even the mild to moderate sun exposure experienced by youngsters who spend time outdoors in Germany during the summer can produce moles with the potential to become cancerous. Light-skinned individuals, as well as those with a family history of skin cancer, are at elevated risk.
SOURCE: Cancer 2003;97:628-638