Validity of Self-reported Solar UVR Exposure Compared with Objectively Measured UVR Exposure

Abstract

Background: Reliance on verbal self-report of solar exposure in skin cancer prevention and epidemiologic studies may be problematic if self-report data are not valid due to systematic errors in recall, social desirability bias, or other reasons. Methods: This study examines the validity of self-reports of exposure to ultraviolet radiation (UVR) compared to objectively measured exposure among children and adults in outdoor recreation settings in 4 regions of the United States. Objective UVR exposures of 515 participants were measured using polysulfone film badge UVR dosimeters on 2 days. The same subjects provided self-reported UVR exposure data on surveys and 4-day sun exposure diaries, for comparison to their objectively measured exposure. Results: Dosimeter data showed that lifeguards had the greatest UVR exposure (24.5% of weekday ambient UVR), children the next highest exposures (10.3% ambient weekday UVR), and parents had the lowest (6.6% ambient weekday UVR). Similar patterns were observed in self-report data. Correlations between diary reports and dosimeter findings were fair to good and were highest for lifeguards (r = 0.38–0.57), followed by parents (r = 0.28–0.29) and children (r = 0.18–0.34). Correlations between survey and diary measures were moderate to good for lifeguards (r = 0.20–0.54) and children (r = 0.35–0.53). Conclusions: This is the largest study of its kind to date, and supports the utility of self-report measures of solar UVR exposure. Impact: Overall, self-reports of sun exposure produce valid measures of UVR exposure among parents, children, and lifeguards who work outdoors. Cancer Epidemiol Biomarkers Prev; 19(12); 3005–12. ©2010 AACR.