Significance of imbalance in the ratio of serum n-3 to n-6 polyunsaturated fatty acids in patients with acute coronary syndrome.

This study aimed to assess the balance of serum n-3 to n-6 polyunsaturated fatty acids (PUFAs) in patients with acute coronary syndrome (ACS). We enrolled 1,119 patients who were treated and in whom serum PUFA level was evaluated in 5 divisions of cardiology in a metropolitan area in Japan. Serum levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA), were compared between patients with and without ACS. We also evaluated the balance of serum n-3 to n-6 PUFAs, including EPA/AA and DHA/AA ratios. EPA/AA values were 0.46 ± 0.32 and 0.50 ± 0.32 in the ACS and non-ACS groups, respectively. DHA/AA values were 0.95 ± 0.37 and 0.96 ± 0.41 in the ACS and non-ACS groups, respectively. Next, we divided the patients into 3 groups based on the tertiles of EPA/AA or tertiles of DHA/AA to determine the independent risk factors for ACS. According to multivariate logistic regression analysis, the group with the lowest EPA/AA (≤0.33) had a greater probability of ACS (odds ratio 3.14, 95% confidence interval 1.16 to 8.49), but this was not true for DHA/AA. In conclusion, an imbalance in the ratio of serum EPA to AA, but not in the ratio of DHA to AA, was significantly associated with ACS.