Higher Frequency of Fish Intake May Be Associated with a Lower Neutrophil/Lymphocyte Ratio: Anti-Atherosclerotic Effects of Fish Consumption

Background: Higher fish consumption has been reported to be associated with a lower incidence of coronary artery disease (CAD). An elevated neutrophil/lymphocyte ratio (NLR), a marker of systemic inflammation, is reportedly associated with the development of adverse CAD events. We hypothesized that a higher fish intake was associated with a lower NLR. Methods and Results: This cross-sectional study was conducted in a cohort of 8,237 Japanese subjects who had no history of atherosclerotic cardiovascular disease registered at the Health Planning Center of Nihon University Hospital between April 2018 and March 2019. The average weekly frequency of fish intake was 2.32 ± 1.31 days. The NLR decreased significantly as the weekly frequency of fish intake (0 day, 1-2 days, 3-4 days, or 5-7 days) increased (p = 0.001). A multiple stepwise regression analysis identified the weekly frequency of fish intake (β = -0.045, p < 0.0001) and habitual alcohol intake (β = -0.051, p < 0.0001) as significant but weak, negative, and independent determinants of the NLR. Conversely, the presence of metabolic syndrome (β = 0.046, p < 0.0001), the presence of treatment for diabetes mellitus (β = 0.054, p < 0.0001), and the presence of treatment for hypertension (β = 0.043, p < 0.0001) were significant positive and independent determinants of the NLR. Conclusions: The present results suggest that a higher frequency of fish intake appears to be associated with a lower NLR, suggesting an anti-systemic inflammation effect. This association may partially explain the preventive effects of a higher fish intake on CAD events.