Intermittent and Chronic Ultraviolet Light Exposure and Uveal Melanoma: a Meta-analysis

Objective: To examine the association between ultraviolet light exposure and uveal melanoma.

Design: Meta-analysis.

Methods: A review of 133 published reports on risk factors for uveal melanoma revealed 12 studies that provided sufficient information to calculate odds ratios (ORs) and standard errors for ultraviolet light exposure factors. Data from these studies were extracted and categorized into intermittent ultraviolet exposure factors (welding, outdoor leisure, photokeratitis) and chronic ultraviolet exposure factors (occupational sunlight exposure, birth latitude, lifetime ultraviolet exposure index). Summary statistics were calculated for all risk factors reported by > or =4 independent studies.

Main Exposure Measures: Welding, outdoor leisure, photokeratitis, occupational sunlight exposure, birth latitude, and lifetime ultraviolet exposure index.

Results: For intermittent ultraviolet exposure, welding was found to be a significant risk factor (5 studies, 1137 cases; OR, 2.05 [95% confidence interval [CI], 1.20-3.51]). Outdoor leisure was found to be nonsignificant (4 studies, 1332 cases; OR, 0.86 [95% CI, 0.71-1.04]). Photokeratitis conferred susceptibility in 3 reports studying this variable, but there were too few studies to validate meta-analyses. For chronic ultraviolet exposure, meta-analysis found occupational sunlight exposure to be a borderline nonsignificant risk factor for development of uveal melanoma (4 studies, 572 cases; OR, 1.37 [95% CI, 0.96-1.96]). Latitude of birth was found to be nonsignificant (5 studies, 1765 cases; OR, 1.08 [95% CI, 0.67-1.74]).

Conclusion: This meta-analysis yielded inconsistent results associating ultraviolet light with development of uveal melanoma. There was evidence implicating welding as a possible risk factor for uveal melanoma.