Background and Objective: Fish intake may prevent cerebrovascular disease (CVD), yet the mechanisms are unclear, especially regarding its impact on subclinical damage. Assuming that fish may have pleiotropic effect on cerebrovascular health, we investigated the association of fish intake with global CVD burden based on brain MRI markers.

Methods: This cross-sectional analysis included participants from the Three-City Dijon population-based cohort study (aged ≥65 years) without dementia, stroke, or history of hospitalized cardiovascular disease, who underwent brain MRI with an automated assessment of white matter hyperintensities, visual detection of covert infarcts, and grading of dilated perivascular spaces. Fish intake was assessed through a frequency questionnaire and the primary outcome measure of CVD burden was defined as the first component of a factorial analysis of mixed data applied to MRI markers. The association of fish intake with the CVD burden indicator was studied using linear regressions.

Results: In total, 1,623 participants (mean age, 72.3 years; 63% women) were included. The first component of factorial analysis (32.4% of explained variance) was associated with higher levels of all three MRI markers. Higher fish intake was associated with lower CVD burden. In a model adjusted for total intracranial volume, compared to participants consuming fish less than once a week, those consuming fish 2 to 3 times per week and ≥4 times per week had a β = -0.19 units (95% CI, -0.37; -0.01) and β = -0.30 (-0.57; -0.03) lower indicator of global CVD burden, respectively (P for trend <0.001). We found evidence of effect modification by age, so that the association of fish to CVD was stronger in younger participants (65-69 years) and not significant in the older age group (≥75 years). For comparison, in the younger age group, consuming fish 2-3 times a week was roughly equivalent (in the opposite direction) to the effect of hypertension, and consuming fish ≥4 times had double that effect.

Discussion: In this large population-based study, higher frequency of fish intake was associated with lower CVD burden, especially among participants younger than 75 years, suggesting a beneficial effect on brain vascular health before manifestation of overt brain disease.