Lifetime ambient uv radiation exposure and risk of basal cell carcinoma by anatomic site in a nationwide U.S. cohort, 1983–2005

Background: Cutaneous basal cell carcinoma (BCC) has long been associated with UV radiation (UVR) exposure, but data are limited on risks by anatomic site. Methods: We followed 63,912 cancer-free White U.S. radiologic technologists from cohort entry (1983–1989/1994–1998) to exit (date first BCC via 2003–2005 questionnaire). We estimated associations between cumulative ambient UVR and relative/absolute risks of self-reported BCC by anatomic location via Poisson models. Results: For incident first primary BCC in 2,124 subjects (mean follow-up, 16.9 years) log[excess relative risks] (ERR) of BCC per unit cumulative ambient UVR ¼ 1.27/MJ cm–2 [95% confidence interval (CI): 0.86–1.68; Ptrend –2/104 person-year (95% CI: 2.92–7.36; Ptrend trend ¼ 0.003), with lesser increases elsewhere. There were lower relative risks, but higher absolute risks, for those with Gaelic ancestry (P Conclusions: BCC relative and absolute risk rose with increasing cumulative ambient UVR exposure, with absolute risk highest for the head/neck, to a lesser extent in the trunk. Impact: These associations should be evaluated in other White and other racial/ethnic populations along with assessment of possible modification by time outdoors, protective, and behavioral factors.