Association between the ratio of serum n-3 to n-6 polyunsaturated fatty acids and acute coronary syndrome in non-obese patients with coronary risk factor: a multicenter cross-sectional study.

ABSTRACT

BACKGROUND: Previous studies have reported that being overweight, obese, or underweight is a risk factor for ischemic cardiovascular disease (CVD); however, CVD also occurs in subjects with ideal body mass index (BMI). Recently, the balance of n-3/n-6 polyunsaturated fatty acids (PUFAs) has received attention as a risk marker for CVD but, so far, no study has been conducted that investigates the association between BMI and the balance of n-3/n-6 PUFAs for CVD risk. METHODS: We evaluated the association between n-3/n-6 PUFA ratio and acute coronary syndrome (ACS) in three BMI-based groups (< 25 low BMI, 25-27.5 moderate BMI, and ≥ 27.5 high BMI) that included 1666 patients who visited the cardiovascular medicine departments of five hospitals located in urban areas in Japan. RESULTS: The prevalence of ACS events was 9.2, 7.3, and 10.3% in the low, moderate, and high BMI groups, respectively. We analyzed the relationship between ACS events and several factors, including docosahexaenoic acid/arachidonic acid (DHA/AA) ratio by multivariate logistic analyses. In the low BMI group, a history of smoking (odds ratio [OR] 2.47, 95% confidence interval [CI] 1.40-4.35) and low DHA/AA ratio (OR 0.30, 95% CI 0.12-0.74) strongly predicted ACS. These associations were also present in the moderate BMI group but the magnitude of the association was much weaker (ORs are 1.47 [95% CI 0.54-4.01] for smoking and 0.63 [95% CI 0.13-3.10] for DHA/AA). In the high BMI group, the association of DHA/AA (OR 1.98, 95% CI 0.48-8.24) was reversed and only high HbA1c (OR 1.46, 95% CI 1.03-2.08) strongly predicted ACS. The interaction test for OR estimates (two degrees of freedom) showed moderate evidence for reverse DHA/AA ratio-ACS associations among the BMI groups (P = 0.091). CONCLUSIONS: DHA/AA ratio may be a useful marker for risk stratification of ACS, especially in non-obese patients.