In prior studies, an increase in the number of acquired nevi has been
associated with increasing risk of cutaneous malignant melanoma in white populations.
To determine whether use of broad-spectrum, high–sun-protection sunscreen
would reduce the development of acquired nevi in children, Gallagher and colleagues
randomly assigned white school-aged children to receive a supply of SPF 30
broad-spectrum sunscreen with instructions for use or to a control group with
no intervention. After 3 years, children in the sunscreen group, especially
those with more facial freckling, developed significantly fewer new nevi than
those in the control group.