Ultraviolet radiation and incidence of cataracts in a nationwide US cohort

Purpose: We examine the risk of cataract and cataract surgery with measures of ultraviolet radiation (UVR) exposure and UVR sensitivity in a large, nationwide population of indoor workers. Methods: Participants from the US Radiologic Technologists Study were followed from age at baseline survey (2003-2005) to age at earliest of cataract diagnosis, cataract surgery, or completion of last survey (2012-2013). UVR-related factors included satellite-based ambient UVR linked to lifetime residences, time spent outdoors across various age periods, history of blistering sunburns, prior diagnosis of keratinocyte carcinoma, and iris color. We used Cox proportional hazards models with age as timescale to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for cataract and cataract surgery. Results: Participants had a median age of entry of 54.0years, were 80.0% female, and 95.7% white. Of the 44,891 eligible participants, 9399 cases of cataract and 3826 cases of cataract surgery were reported. Ambient UVR (quintile 5 vs. 1) was associated with an increased risk of cataract (HR = 1.08; 95% CI: 1.01-1.16) and cataract surgery (HR = 1.16; 95% CI: 1.05-1.29). Lifetime average time spent outdoors was not associated with cataract risk. History of blistering sunburns before and after age 15, but not previous keratinocyte carcinoma diagnosis was associated with both cataract and cataract surgery. Conclusion: Our results suggest a modest role for residence-based ambient UVR and cataract risk among indoor workers in the United States.