Dietary Oily Fish Intake is Inversely Associated with Severity of White Matter Hyperintensities of Presumed Vascular Origin. A Population-Based Study in Frequent Fish Consumers of Amerindian Ancestry

Background: Oily fish is a major dietary source of omega-3 polyunsaturated fatty acids and other nutrients that may reduce the expression of cerebral small vessel disease (cSVD) biomarkers, including white matter hyperintensities (WMH) of presumed vascular origin. However, information on this relationship is limited. We aimed to assess the association between oily fish intake and WMH severity in a population of frequent fish consumers. Methods: The study included 572 individuals aged ≥60 years living in three neighboring rural villages of coastal Ecuador. Dietary oily fish intake was calculated and all participants received a brain MRI. Logistic regression models, adjusted for demographics, level of education, cardiovascular risk factors and other cSVD biomarkers, were fitted to assess the independent association between amounts of oily fish intake and WMH severity. Results: Overall, the mean intake of oily fish was 8.5 ± 4.7 servings per week, and 164 individuals (29%) had moderate-to-severe WMH (according to the modified Fazekas scale). A multivariate logistic regression model disclosed a significant inverse association between the amount of oily fish intake and the presence of moderate-to-severe WMH (OR: 0.89; 95% C.I.: 0.85–0.94; p < 0.001). Predictive margins revealed an almost linear inverse relationship between quartiles of oily fish intake and probabilities of WMH severity, which became significant when the 1^st quartile was compared with the 3^rd and 4^th quartiles. Conclusions: Increased amounts of oily fish intake are inversely associated with WMH severity. Further studies are warranted to determine whether oily fish intake reduces the risk of cSVD-related cerebrovascular complications.