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 (CI 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; CI 1.16-5.73, p = 0.020) and in the second highest quartile (odds ratio = 3.27; CI 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.