Residential History and Solar Exposure in Relation to Exfoliation Syndrome in the United States and Israel

Abstract

Purpose: To assess the relation between residential history, solar exposure and risk of exfoliation syndrome (ES).

Methods: We conducted a prospective, cross-sectional observational, case-control study at 2 clinical centers: Massachusetts Eye & Ear Infirmary in the United States (US) and the Goldschleger Eye Institute in Israel. Cases demonstrated exfoliation precipitates in at least one eye with or without glaucoma while controls lacked these precipitates on dilated fundus exam. Masked interviewers administered validated residential and solar exposure questionnaires to assess exposure from birth to age 60 in subjects from the US (118 cases, 106 controls) and Israel (67 cases, 72 controls). We developed logistic regression models to estimate the multivariate odds ratio (MV OR) and 95% confidence intervals (CI) of ES at each site separately and pooled the results with meta-analysis.

Results: After adjusting for multiple covariates including age and gender, each degree of weighted lifetime average latitude spent away from the equator was associated with an 11% increased risk of ES (pooled MV OR=1.11, 95% CI: 1.05-1.17; p=0004). After adjustment for lifetime residential history and other covariates, every extra hour per week spent outdoors was associated with a 3% increased risk of ES (pooled MV OR=1.03, 95% CI: 1.00-1.06; p=0.04). For every 1% of time in the summer between 10am and 4pm that sunglasses were worn, the risk of ES decreased by 2% (MV OR=0.98, 95% CI: 0.97-0.99) at the US site but these results were not reproduced at the Israeli site (MV OR=1.00, 95% CI: 0.99-1.01; p=0.98); however, data from both sites were statistically heterogeneous (p for heterogeneity=0.005) and could not be pooled. History of work over either water or over snow was associated with increased risk of ES (MV OR=3.86 (95% CI: 1.36-10.9) in the US even after controlling for weighted lifetime average latitude, sunglass wear and lifetime average number of hours spent outside per week. Too few people in Israel had comparable occupations for analysis. In no model was brimmed hat wear associated with ES risk.

Conclusions: These data suggest that solar exposure contributes to ES. Furthermore, the stronger association with work over snow or water in conjunction with the absence of protection from brimmed hats suggests that light rays incident off reflective surfaces is critical for the development of ES.

Keywords: 464 clinical (human) or epidemiologic studies: risk factor assessment