Incidence of nonmelanoma skin cancer in relation to ambient UV radiation in white populations, 1978-2012: empirical relationships.

IMPORTANCE Nonmelanoma skin cancers (NMSCs) are the most common cancers in fair-skinned populations. Their incidence continues to increase in many countries. Exposure to UV radiation (UVR) is the primary cause of NMSC, although the pattern of exposure that gives rise to different types of NMSC appears to vary. OBJECTIVE To examine dose-response relationships between ambient UVR levels and NMSC incidence at the population level. DESIGN, SETTING, AND PARTICIPANTS Peer-reviewed literature published from January 1, 1978, through December 31, 2012, that provided age- and sex-specific incidence of NMSC in white populations worldwide was systematically reviewed. EXPOSURES Mean erythemally weighted daily ambient UVR levels for each study location were derived from satellite data. MAIN OUTCOMES AND MEASURES The incidence of NMSC in white populations worldwide as reported in population-based studies. RESULTS Forty eligible publications were included in the analysis. Analysis models that contained age group, sex, study year, mean daily UVR, and day-to-day variability of UVR explained most of the variability in NMSC incidence: 82% for basal cell carcinoma (BCC) and 85% for squamous cell carcinoma (SCC). Exclusion of studies in which imputation of age-specific incidence data from standardized rates was required improved the model fit to 85% for BCC and 88% for SCC. Higher mean daily UVR was associated with higher NMSC incidence rates; this was greater in men than women for BCC (70% vs 60%) but greater in women for SCC (99% vs 92%). Incidence rates for BCC and SCC were higher among those older than 60 years, but the increase with age was steeper for those younger than 60 years. CONCLUSIONS AND RELEVANCE Our models highlight the etiologic differences between BCC and SCC and allow prediction of NMSC incidence for data-poor regions and under changing demographic and environmental conditions.