Adherence to a Mediterranean diet and its association with age-related macular degeneration. The Coimbra Eye Study-Report 4

Objectives: This study aimed to characterize the association of lifestyle and nutritional risk profiles with age-related macular degeneration (AMD) in two subpopulations with differing AMD prevalence.

Methods: This case-control study (n = 1992) included 768 patients with AMD and 1224 age- and sex-matched participants without AMD with a single visit at a primary health care unit. Enrolled participants completed a validated lifestyle and food frequency questionnaire. A score to measure adherence to the Mediterranean diet (mediSCORE; Range, 0-9) was constructed from individual food intakes, which were further analyzed by conversion to nutrient consumption.

Results: Higher adherence to the Mediterranean diet (mediSCORE ≥6) was significantly associated with no AMD (odds ratio [OR] = 0.73; P = 0.009). The subpopulation with lower AMD prevalence presented significantly higher adherence to the Mediterranean diet in relation to all individual food groups that comprised the mediSCORE (P < 0.014) with the exception of cereals. Food group analysis showed significant associations between the increased consumption of vegetables (OR = 0.63; P < 0.001) and fruit and nuts (OR = 0.78; P = 0.010) with no AMD. Nutrient analysis revealed that an increased ingestion of water, fibers, total fat, monounsaturated and polyunsaturated fatty acids, linoleic acid, vitamins A and C, carotene, alpha-tocopherol, folate, magnesium, iron, and zinc were significantly associated with no AMD (P < 0.0013). Finally, regular physical activity was associated with no AMD (P = 0.003).

Conclusions: High adherence to a Mediterranean diet and regular physical activity seem to be protective factors for AMD in a Portuguese population. The effect of the diet is likely driven by the increased consumption of vegetables, fruits, and nuts.