Tanning and increased nevus development in very-light-skinned children without red hair

Objective: To examine the relationship between tanning and nevus development in very-light-skinned children. Design: Prospective cohort nested within a randomized controlled trial. Skin examinations in 3 consecutive years (2004, 2005, and 2006) included full-body counts of nevi, skin color and tanning measurement using colorimetry, and hair and eye color evaluation by comparison with charts. Telephone interviews of parents provided sun exposure, sun protection, and sunburn history. Setting: Large managed-care organization and private pediatric offices in the Denver, Colorado, metropolitan area. Participants: A total of 131 very-light-skinned white children without red hair and 444 darker-skinned white children without red hair born in Colorado in 1998. Main Outcome Measures: Full-body nevus counts at ages 6 to 8 years. Results: Among very-light-skinned white children, geometric mean numbers of nevi for minimally tanned children were 14.8 at age 6 years; 18.8 at age 7 years; and 22.3 at age 8 years. Mean numbers of nevi for tanned children were 21.2 at age 6 years; 27.9 at age 7 years; and 31.9 at age 8 years. Differences in nevus counts between untanned and tanned children were statistically significant at all ages (P<.05 for all comparisons). The relationship between tanning and number of nevi was independent of the child's hair and eye color, parent-reported sun exposure, and skin phototype. Among darker-skinned white children, there was no relationship between tanning and nevi. Conclusions: Very-light-skinned children who tan (based on objective measurement) develop more nevi than children who do not tan. These results suggest that lightskinned children who develop tans may be increasing their risk for developing melanoma later in life.