Dietary oily fish intake and progression of diffuse subcortical damage of vascular origin: A longitudinal prospective study in community-dwelling older adults

Abstract

Introduction: Oily fish intake may reduce the progression of white matter hyperintensities (WMH) of presumed vascular origin due to their high content of omega-3 polyunsaturated fatty acids and other nutrients. However, information on this relationship is limited. We aimed to assess the association between oily fish intake and WMH progression in older adults living in rural coastal Ecuador.

Methods: Participants of the Atahualpa Project Cohort received baseline clinical interviews and brain MRIs. Oily fish intake was calculated at every annual door-to-door survey from enrollment to the end of the study. Individuals who also received a follow-up brain MRI were included. Poisson regression models were fitted to assess the incidence rate ratio (IRR) of WMH progression according to the amount of oily fish intake, after adjusting for demographics, level of education and traditional vascular risk factors.

Results: The study included 263 individuals of Amerindian ancestry aged ⩾60 years (mean age: 65.7 ± 6.2 years; 57% women). The mean oily fish intake was 8.3 ± 4 servings per week. Follow-up MRIs demonstrated WMH progression in 103 (39%) individuals after a median follow-up of 6.5 years. A multivariate Poisson regression model showed an inverse relationship between oily fish intake and WMH progression (IRR: 0.89; 95% CI: 0.84-0.95; p < 0.001). A similar model also revealed an inverse relationship between tertiles of oily fish intake and probabilities of WMH progression, which became significant when individuals allocated to the third tertile were compared to those in the first and second tertiles.

Conclusion: Study results show an inverse relationship between the amount of oily fish intake and WMH progression in frequent fish consumers of Amerindian ancestry.

Keywords: Oily fish intake; cerebral small vessel disease; omega-3 polyunsaturated fatty acids; prospective cohort study; white matter hyperintensities.

Figure 1.

Fluid-attenuated inversion recovery MRI of a 65 years-old man allocated to the first tertile of dietary oily fish intake (less than 6.58 fish servings per week) showing progression of white matter hyperintensities from baseline MRI performed in June 2015 (upper row), to follow-up MRI performed in June 2021 (lower row).

Figure 2.

Graph plot showing an inverse relationship between tertiles of oily fish intake (servings per week) and probabilities of white matter hyperintensities (WMH) progression, which became significant (no overlapping 95% confidence intervals) when the third tertile were compared with the first and second tertiles.