Australia has one of the highest rates of skin cancer globally. Lifetime risk is associated with childhood sun exposure.

We sought to investigate whether skin cancer prevention programs have resulted in improvements in sun-exposure and sun-protection behavior among young children in tropical Australia.

Two cohorts of 12-to 35-month-old children from Townsville, Australia, were compared: cohort 1 was recruited from hospital birth records (1991) and cohort 2 was recruited via local child-care centers (1999-2002). Children’s phenotypic characteristics were assessed. Parents completed questionnaires detailing children’s demographic characteristics, and sun-exposure and sun-protective practices.

Although 1-year-old children from cohort 2 spent more time in the sun than those from cohort 1 (median 2.2 vs 2.8 h/d; P = .002), a higher proportion almost always wore sunscreen and a swim-shirt year round. Although more 1-year-old children in cohort 2 had experienced a sunburn (35.5% vs 51.2%; P = .007), both cohort 2 age groups experienced fewer hours of sun exposure to the back of the trunk (P < .001), were less likely to have been sunburned on the back/shoulders (age 1 year 34.8% vs 10.1% and age 2 years 52% vs 10.1%; P < .001), and acquired fewer melanocytic nevi at these sites (P < .001).

There was potential for socially desirable responses (information bias).

Although duration of sun exposure in early childhood did not decrease during an 8-year period, reported use of personal sun protection did. The observed increase in popularity of swim-shirts and sunscreen between cohorts coincided with the development of significantly fewer melanocytic nevi in these children.