Sunlight and Risk of Age-related Macular Degeneration: The Irish Nun Eye Study (INES)

Abstract

Purpose : To estimate the prevalence of age-related macular degeneration (AMD) in a population of women with a restricted lifestyle and to investigate the association between lifetime sunlight exposure and AMD.

Methods : Cross-sectional study of 1233 nuns aged > 60 years in the island of Ireland. Structured questionnaires were completed for demographic information, medical history, AMD risk factors, dietary intake and sunlight exposure. Retinal status was assessed by stereo retinal photography. Lifetime ambient exposure and ocular ambient exposure for both ultraviolet B (UVB) and visible light, as well as lifetime retinal irradiance were calculated. Logistic regression models were used to examine the association between these measures of light exposure and risk of AMD.

Results : AMD prevalence was: 21.4% (grade 1); 9.1% (grade 2); 3.0% (grade 3); and 6.0% (grade 4). Geographic atrophy was present in 1.2% and neovascular AMD in 4.8% Comparison of late AMD rates with other populations using the Indirect Standardised Age Specific Disease Rate was 85.4 versus EUREYE (lower, but not significant) and 78.4 versus the EDPRG (significantly lower). The prevalence of drusen ≥125um in those >80 years was 13.5% in INES compared to 28.9% and 29.2% in age-matched populations (significant).

Age-adjusted multivariable association of quintiles of light exposure with any AMD were calculated. No light exposure variable was associated with AMD status, by comparing upper and lower quintiles, among the following: Total childhood UV exposure (OR: 0.874, 95%CI: 0.563 – 1.357; p= 0.548); Total lifetime corrected UV exposure (or Irish Standard Years: OR: 1.146, 95%CI: 0.708 – 1.855; p= 0.579); Total visible reflected ground luminance (OR: 1.064, 95%CI: 0.652 – 1.736; p=0.804); Blue retinal irradiance (OR: 0.893, 95%CI: 0.579 – 1.377; p=0.608). Tests for linear trends were also not significant. Although AMD grade was not associated with any measure of ultraviolet or visible light nor with lifetime retinal irradiance, significantly more drusen were present in light exposed areas of the macula.

Conclusions : Although a higher prevalence of large drusen in light exposed areas of the macula were observed, there was no association between estimates of cumulative light exposure and AMD grade.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.