Greater Adherence to a Mediterranean Diet is Associated with lower C-reactive Protein (CRP) levels, but not to lower odds of having Dry Eye Disease

Purpose: To investigate the hypothesis that a Mediterranean diet is associated with a lower risk of having dry eye disease (DED) in the general population.

Methods:
DED was assessed using the Women’s Health Study (WHS) dry eye questionnaire in 58,993 participants from the Dutch Lifelines Cohort with complete available dietary data (20-94 years, 60% female). Level of adherence to a traditional Mediterranean diet was assessed using the modified Mediterranean Diet Score (mMDS). High-sensitivity C-reactive Protein (hsCRP) was included as a marker of whole-body inflammation. Logistic regressions were used to examine the relationship between WHS-defined DED and mMDS, corrected for age, sex, BMI, education, income, and 48 potentially confounding comorbidities. The association between mMDS and hsCRP, and hsCRP and DED, was further explored in separate regressions.

Results: 
Of all participants, 9.1% had DED. In contrast to the hypothesis, higher mMDS levels were associated with greater odds of DED, corrected for demographics, smoking status, BMI, and comorbidities (OR 1.034, 95%CI: 1.015 to 1.055, P=0.001). Moreover, there was a highly significant relationship between increasing mMDS and lower circulating hsCRP levels; however, there was no significant relationship between hsCRP and DED.

Conclusions:
Stronger adherence to a Mediterranean diet does not appear to be associated with lower odds of having DED in the general population. Furthermore, there was no association between hsCRP and DED in this study. However, the previously described link between a Mediterranean diet and lower hsCRP was confirmed in this large population-based study.