Abstract
Purpose: :
Recent studies have suggested that dietary intake of the antioxidant xanthophyll carotenoids lutein and zeaxanthin (L/Z) and fats may alter the risk of age–related macular degeneration (AMD). We examined the potential effect of L/Z and fats on AMD progression, which remains unresolved.
Methods: :
A cohort of 254 subjects with previously identified early AMD were re–examined after an average of 7 years to determine AMD progression based on 3 different definitions. A food frequency questionnaire administered at follow–up was used to estimate intake of L/Z and fatty acids. Multivariate analysis included age, smoking, AMD family history, study source and follow–up duration as covariates.
Results: :
Energy–adjusted L/Z intake was positively associated with AMD progression defined as an increase in AMD severity by >=1 level in the worse affected eye (OR=2.65, 95% CI 1.13–6.22). Similar trends were observed for the other two definitions of progression (p=0.15 and p=0.14 respectively). Energy–adjusted n–3 fatty acid intake was significantly associated with AMD progression in side–by–side comparison of baseline and follow up macular photos (OR=2.56, 95% CI 1.11–5.91). The association was of borderline significance for the other two definitions of progression (p=0.05 and p=0.08). No association of AMD progression with the intake of either total fat or other subgroups: saturated, polyunsaturated or monounsaturated fats, trans fatty acids or n–6 fatty acids was observed.
Conclusions: :
This study does not support a protective effect of LZ and n–3 fatty acids intake on AMD progression; in fact the associations of these nutrients with progression were positive. The possibility remains that those at higher risk of progression altered their diets to increase their intakes of carotenoids and n–3 fats in response to a diagnosis of AMD and predictions about possible visual loss.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment