The relationship between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women

Abstract

Background: Dry eye syndrome (DES) is a prevalent ocular condition, but information on risk or protective factors is lacking. Objective: We aimed to determine the association between dietary intake of n-3 and n-6 fatty acids and their ratio and the presence of DES. Design: Of the 39,876 female health professionals in the Women's Health Study (WHS), we studied cross-sectionally 32,470 women aged 45 to 84 years who provided information on diet and DES. We assessed intake of fatty acids by a validated food frequency questionnaire, and DES using self-reports of clinically diagnosed cases. Of the sample, 1546 (4.7%) subjects reported a clinical diagnosis of DES. We used logistic regression models to estimate the odds ratios (OR) and 95% confidence intervals (CI) to describe the relationships of fatty acid intake with DES. We analyzed the association between consumption of fish and DES in a similar way. Results: After adjusting for demographic factors, hormone therapy, and total fat intake, the OR (CI) for the highest versus lowest fifth of n-3 fatty acids was 0.83 (0.70-0.98), P[trend]=0.05. A higher ratio of n-6/n-3 fatty acid consumption was associated with significantly increased risk of DES, OR (CI) =2.51 (1.13-5.58) for >15/1 versus <4/1 (P[trend]=0.01). In addition, tuna consumption was inversely associated with DES (OR=0.81, CI=0.66-0.99 for 2-4 113 g (4 oz) servings/week, and OR=0.32, CI=0.13-0.79 for 5-6 servings/week versus ≤1 servings/week; P[trend]=0.005). Conclusion: These results suggest that a higher dietary intake of n-3 fatty acids is associated with a decreased presence of DES in women. These findings are consistent with anecdotal clinical observations and postulated biological mechanisms.