Precursors of age-related macular degeneration: associations with vitamin A and interaction with CFHY402H in the Inter99 Eye Study

Purpose: To investigate associations of very early age-related macular degeneration (AMD) with daily intake of vitamin A, beta-carotene, vitamin E, vitamin C, zinc and copper and interactions with AMD-associated polymorphisms in complement factor H (CFHY402H) and ARMS2/LOC387715.

Methods: Cross-sectional study of 848 subjects aged 30-60 years from the Inter99 Eye Study. Daily intake of vitamins and minerals was estimated from a 198-item food frequency questionnaire. Digital fundus photographs were recorded in red-free illumination and graded for macular drusen >63 μm and numerous (>20) small hard macular drusen as a mean of both eyes.

Results: Higher intake of vitamin A increased the risk of having macular drusen >63 μm with odds ratio = 1.82 (CI₉₅ 1.02-3.24, p = 0.042) comparing participants in the highest quartile of vitamin A intake with participants in the lowest quartile, adjusted for recruitment group, age and sex. There was a significant interaction with CFHY402H (p = 0.038). Among 504 participants with CFHY402H, the relative risk of having macular drusen >63 μm was increased in participants in the highest quartile of vitamin A intake (odds ratio = 2.58; CI₉₅ 1.16-5.73, p = 0.020) and in the second highest quartile (odds ratio = 3.27; CI₉₅ 1.50-7.13, p = 0.0029) compared with the lowest quartile. Further adjusting for total fat intake, energy intake, plasma cholesterol, body mass index (BMI), smoking, alcohol intake, education and physical activity strengthened the association.

Conclusions: In this cross-sectional study, a higher intake of vitamin A increased the risk of macular drusen >63 μm in subjects with CFHY402H. The study supports that vitamin A may be a risk factor for early AMD.