Host Factors, UV Radiation, and Risk of Uveal Melanoma: A Case-Control Study

Uveal melanoma threatens life, as well as sight. To evaluate the effect of constitutional factors and UV radiation on the risk of uveal melanoma, 197 cases in New England were compared with 385 matched population controls, identified by random-digit dialing, and 337 cases residing within the United States were compared with 800 sibling controls. In the population-based comparison, estimated relative risks (RRs) of uveal melanoma, after adjustment for other factors, were elevated for the following: ancestry from more northern latitudes with a substantially elevated risk for Northern European ancestry (RR, 6.5; 95% confidence interval [CI], 1.9 to 22.4) and more than a twofold risk for British ancestry (RR, 2.4; 95% CI, 1.1 to 5.1), as compared with Southern European or other Mediterranean heritage; light skin color as compared with dark (RR, 3.8; 95% CI, 1.1 to 12.6); and 10 or more cutaneous nevi as compared with none (RR, 2.7; 95% CI, 1.5 to 4.9). There was a statistically significant trend for increasing risk with more northern heritage and more moles. Southern residence (below latitutde 40° N) for more than 5 years also increased risk (RR, 2.8; 95% CI, 1.1 to 6.9), as compared with none. In both comparisons, use of sunlamps was a risk determinant (RR, 3.4; 95% CI, 1.1 to 10.3 with random-digit dialed controls and RR, 2.3; 95% CI, 1.2 to 4.3 with sibling controls, comparing occasional or frequent use to never use), as was intense sun exposure (RR, 1.7; 95% CI, 0.9 to 3.0 and RR, 2.1; 95% CI, 1.4 to 3.2, respectively). However, birthplace below latitude 40° N and outdoor work were associated with a lower risk. Results indicate that personal attributes are strong independent risk factors for uveal melanoma, and new host factors, ancestry and moles, are identified. Some but not all of the evaluated indexes of UV exposures were related to a small to moderate increased risk of this potentially fatal disease.