Abstract
BACKGROUND: In cohort studies, elevated levels of plasma nonesterified free fatty acids (NEFAs) have been associated with increased risk of sudden cardiac death (SCD) in men, but blood samples were drawn several years before SCD. OBJECTIVE: To confirm this relationship by evaluating levels of plasma NEFAs at the time of the SCD event in a group of both men and women. METHODS: From the ongoing Oregon Sudden Unexpected Death Study, we compared levels of plasma NEFAs in 149 SCD cases presenting with ventricular fibrillation (mean age 64 ± 12 years; 73% men) and 149 age- and sex-matched controls with coronary artery disease. Plasma was processed from blood drawn at the time of arrest (cases) and at a routine visit (controls). The levels of plasma NEFAs were compared after categorizing into quartiles on the basis of control values. Conditional logistic regression was used to predict adjusted odds ratio for SCD associated with plasma NEFA levels per increased quartile. RESULTS: The plasma NEFA levels were significantly higher in SCD cases than in controls (median 0.39 mmol/L [interquartile range 0.28-0.60 mmol/L] vs 0.32 mmol/L [interquartile range 0.20-0.49 mmol/L]; P = .002). There were no significant differences in body mass index, smoking, and diabetes. The odds ratio for SCD was 1.42 (95% confidence interval 1.14-1.78) per quartile increase in the plasma NEFA level (P = .002). Individuals with plasma NEFA levels above the prespecified cutoff point of 0.32 mmol/L were at increased risk of SCD (odds ratio 2.00; 95% confidence interval 1.20-3.34; P = .008). CONCLUSION: These findings strengthen the role of plasma NEFA as a potential biomarker for the assessment of SCD risk.