Association of Higher N-3 Polyunsaturated Fatty Acid Consumption and Aerobic Exercise with Lower Neutrophil-to-Lymphocyte Ratio: Implications of Anti-Atherosclerotic Effect of Fish Consumption

Introduction: N-3 polyunsaturated fatty acids (n-3 PUFAs), abundant in oily fish, exert anti-inflammatory cardiovascular protective effects. We aimed to investigate the association between fish-derived n-3 PUFAs, lifestyle habits, and neutrophil-to-lymphocyte ratio (NLR), an atherosclerotic cardiovascular disease (ASCVD) marker. Methods: This cross-sectional study included 6,950 participants with no history of ASCVD, who underwent annual health check-ups (average age, 46.3 ± 13.0 years; male:female ratio, 58.8%) between April 2019 and March 2020 at the Health Planning Center, Nihon University Hospital. We calculated n-3 PUFA consumption using a questionnaire and the Japan National Health and Nutrition Survey. Results: The average fish consumption frequency and fish-derived n-3 PUFA consumption were 2.20 ± 1.28 days/week and 5.20 ± 3.11 g/week, respectively. A higher fish-derived n-3 PUFA consumption was associated with a lower NLR. Multiple-stepwise regression analysis revealed that higher fish-derived n-3 PUFA consumption and more aerobic exercise habits were significant independent determinants of lower NLR. Furthermore, higher fish-derived n-3 PUFA consumption was associated with habitual aerobic exercise habits. Conclusion: Thus, higher fish-derived n-3 PUFA consumption and more aerobic exercise habits may be synergistically associated with lower NLR. This association may explain the preventive effects of fish consumption on the ASCVD risk.