Prospective study of dietary fat and the risk of age-related macular degeneration

Background: The relation between intakes of total fat and specific types of fat and age-related macular degeneration (AMD) remains unclear. Objective: Our objective was to examine prospectively the association betwe en fat intake and AMD. Design: We conducted a prospective follow-up study of participants in the N urses' Health Study and the Health Professionals Follow-up Study. At baseli ne (1984 for women and 1986 for men), the study included 42743 women and 29 746 men aged greater than or equal to 50 y with no diagnosis of AMD who wer e followed until 1996. Fat intake was assessed with a food-frequency questi onnaire. Results: We accrued 567 patients with AMD with a visual loss of 20/30 or wo rse. The pooled multivariate relative risk (RR) for the highest compared wi th the lowest quintile of total fat intake was 1.54 (95% CI: 1.17, 2.01: P for trend = 0.008). Linolenic acid was positively associated with risk of A MD (top versus bottom quintile of RR: 1.49; 95% CI: 1.15, 1.94; P for trend = 0.0009). Docosahexaenoic acid had a modest inverse relation with AMD (to p versus bottom quintile of RR: 0.70; 95% CI: 0.52, 0.93; P for trend = 0.0 5), and >4 servings of fish/wk was associated with a 35% lower risk of AMD compared with less than or equal to3 servings/mo (RR: 0.65; 95% CI: 0.46, 0 .91; P for trend = 0.009). Conclusions: Total fat intake was positively associated with risk of AMD, w hich may have been due to intakes of individual fatty acids, such as linole nic acid, rather than to total fat intakes per se. A high intake of fish ma y reduce the risk of AMD.