Omega-3 Fatty Acid Biomarkers and Incident Atrial Fibrillation.

BACKGROUND: The relationship between omega-3 fatty acids and atrial fibrillation (AF) remains controversial. OBJECTIVES: This study aimed to determine the prospective associations of blood or adipose tissue levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) with incident AF. METHODS: We used participant-level data from a global consortium of 17 prospective cohort studies, each with baseline data on blood or adipose tissue omega-3 fatty acid levels and AF outcomes. Each participating study conducted a de novo analyses using a prespecified analytical plan with harmonized definitions for exposures, outcome, covariates, and subgroups. Associations were pooled using inverse-variance weighted meta-analysis. RESULTS: Among 54,799 participants from 17 cohorts, 7,720 incident cases of AF were ascertained after a median 13.3 years of follow-up. In multivariable analysis, EPA levels were not associated with incident AF, HR per interquintile range (ie, the difference between the 90th and 10th percentiles) was 1.00 (95% CI: 0.95-1.05). HRs for higher levels of DPA, DHA, and EPA+DHA, were 0.89 (95% CI: 0.83-0.95), 0.90 (95% CI: 0.85-0.96), and 0.93 (95% CI: 0.87-0.99), respectively. CONCLUSIONS: In vivo levels of omega-3 fatty acids including EPA, DPA, DHA, and EPA+DHA were not associated with increased risk of incident AF. Our data suggest the safety of habitual dietary intakes of omega-3 fatty acids with respect to AF risk. Coupled with the known benefits of these fatty acids in the prevention of adverse coronary events, our study suggests that current dietary guidelines recommending fish/omega-3 fatty acid consumption can be maintained.

Plasma Omega-3 Fatty Acids and the Risk of Cardiovascular Events in Patients After an Acute Coronary Syndrome in MERLIN-TIMI 36.

Background Plasma omega-3 polyunsaturated fatty acids (ω3-PUFAs) have been shown to be inversely correlated with the risk of cardiovascular death in primary prevention. The risk relationship in the setting of an acute coronary syndrome is less well established. Methods and Results Baseline plasma ω3-PUFA composition (α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid) was assessed through gas chromatography with flame ionization detection in a case-cohort study involving 203 patients with cardiovascular death, 325 with myocardial infarction, 271 with ventricular tachycardia, and 161 with atrial fibrillation, and a random sample of 1612 event-free subjects as controls from MERLIN-TIMI 36 (Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation-Acute Coronary Syndrome-Thrombolysis in Myocardial Infarction 36), a trial of patients hospitalized with non-ST-segment-elevation -acute coronary syndrome. After inverse-probability-weighted multivariable adjustment including all traditional risk factors, a higher relative proportion of long-chain ω3-PUFAs (eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid) were associated with 18% lower odds of cardiovascular death (adjusted [adj] odds ratio [OR] per 1 SD, 0.82; 95% CI, 0.68-0.98) that was primarily driven by 27% lower odds of sudden cardiac death (adj OR per 1 SD, 0.73; 95% CI, 0.55-0.97). Long-chain ω3-PUFA levels in the top quartile were associated with 51% lower odds of cardiovascular death (adj OR 0.49; 95% CI, 0.27-0.86) and 63% lower odds of sudden cardiac death (adj OR, 0.37; 95% CI, 0.16-0.56). An attenuated relationship was seen for α-linolenic acid and subsequent odds of cardiovascular (adj OR, 0.92; 95% CI, 0.74-1.14) and sudden cardiac death (adj OR, 0.91; 95% CI, 0.67-1.25). No significant relationship was observed between any ω3-PUFAs and the odds of cardiovascular death unrelated to sudden cardiac death, myocardial infarction, atrial fibrillation, or early post-acute coronary syndrome ventricular tachycardia. Conclusions In patients after non-ST-segment-elevation-acute coronary syndrome, plasma long-chain ω3-PUFAs are inversely associated with lower odds of sudden cardiac death, independent of traditional risk factors and lipids. Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT00099788.

Association Between Triglyceride Lowering and Reduction of Cardiovascular Risk Across Multiple Lipid-Lowering Therapeutic Classes: A Systematic Review and Meta-Regression Analysis of Randomized Controlled Trials.

BACKGROUND: Randomized trials of therapies that primarily lowered triglycerides have not consistently shown reductions in cardiovascular events. METHODS: We performed a systematic review and trial-level meta-regression analysis of 3 classes of lipid-lowering therapies that reduce triglycerides to a greater extent than they do low-density lipoprotein cholesterol (LDL-C): fibrates, niacin, and marine-derived omega-3 fatty acids. Key inclusion criteria were a randomized controlled trial that reported major vascular events. We also incorporated data from a previous meta-regression of 25 statin trials. The main outcome measure was the risk ratio (RR) for major vascular events associated with absolute reductions in lipid parameters. RESULTS: A total of 197 270 participants from 24 trials of nonstatin therapy with 25 218 major vascular events and 177 088 participants from 25 trials of statin therapy with 20 962 major vascular events were included, for a total of 374 358 patients and 46 180 major cardiovascular events. Starting with non-high-density lipoprotein cholesterol, a surrogate for very-low-density lipoproteins and low-density lipoproteins, the RR per 1-mmol/L reduction in non-high-density lipoprotein cholesterol was 0.79 (95% CI, 0.76-0.82; P<0.0001; 0.78 per 40 mg/dL). In a multivariable meta-regression model that included terms for both LDL-C and triglyceride (surrogates for low-density lipoproteins and very-low-density lipoproteins, respectively), the RR was 0.80 (95% CI, 0.76-0.85; P<0.0001) per 1-mmol/L (0.79 per 40 mg/dL) reduction in LDL-C and 0.84 (95% CI, 0.75-0.94; P=0.0026) per 1-mmol/L (0.92 per 40 mg/dL) reduction in triglycerides. REDUCE-IT (Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial) was a significant outlier and strongly influential trial in the meta-regression. When removed, the RRs became 0.79 (95% CI, 0.76-0.83; P<0.0001) per 1-mmol/L (0.78 per 40 mg/dL) reduction in LDL-C and 0.91 (95% CI, 0.81-1.006; P=0.06) per 1-mmol/L (0.96 per 40 mg/dL) reduction in triglycerides. In regard to omega-3 dose, each 1 g/d eicosapentaenoic acid administered was associated with a 7% relative risk reduction in major vascular events (RR, 0.93 [95% CI, 0.91-0.95]; P<0.0001), whereas there was no significant association between the dose of docosahexaenoic acid and the relative risk reduction in major vascular events (RR 0.96 [95% CI, 0.89-1.03]). CONCLUSIONS: In randomized controlled trials, triglyceride lowering is associated with a lower risk of major vascular events, even after adjustment for LDL-C lowering, although the effect is less than that for LDL-C and attenuated when REDUCE-IT is excluded. Furthermore, the benefits of marine-derived omega-3 fatty acids, particularly high-dose eicosapentaenoic acid, appear to exceed their lipid-lowering effects.