Dietary linolenic acid and adjusted QT and JT intervals in the National Heart, Lung, and Blood Institute Family Heart study.
OBJECTIVE
The goal of this study was to examine whether higher consumption of total linolenic acid was associated with rate-adjusted QT and JT intervals (QTrr and JTrr, respectively).


BACKGROUND
Higher intake of fish omega-3 fatty acids and plant omega-3 such as alpha-linolenic acid is associated with lower risk of myocardial infarction. While long-chain omega-3 can inhibit ventricular arrhythmia, it is not known whether alpha-linolenic acid influences ventricular repolarization.


METHODS
We studied 3,642 subjects from the National Heart, Lung, and Blood Institute Family Heart study who were free of myocardial infarction, left ventricular hypertrophy, pacemaker, and with QRS <120 ms. We used the 95th percentile of the gender-specific distribution of QTrr and JTrr to define abnormally prolonged repolarization. Within each gender, we created age- and energy-adjusted tertiles of linolenic acid and used regression models for analyses.


RESULTS
Mean age was 50 years, and average intake of total linolenic acid was 0.74 g/day. There was an inverse association between consumption of linolenic acid and QTrr and JTrr (p for trend 0.001 and 0.0005, respectively). From the lowest (reference) to the highest gender-, age-, and energy-adjusted tertile of linolenic acid, multivariable adjusted odds ratios for prolonged QTrr were 1.0, 0.74 (95% confidence interval [CI] 0.57 to 0.96), and 0.59 (95% CI 0.44 to 0.77), respectively (p for trend 0.0003). Corresponding values for JTrr were 1.0, 0.73 (95% CI 0.52 to 1.03), and 0.59 (95% CI 0.40 to 0.87), respectively (p for trend 0.009). Exclusion of subjects taking drugs known to influence QT did not influence this association.


CONCLUSIONS
Higher intake of dietary linolenic acid might be associated with a reduced risk of abnormally prolonged repolarization in men and women.
Djoussé
Luc
L
Section of Preventive Medicine & Epidemiology, Evans Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA. ldjousse@bu.edu
Rautaharju
Pentti M
PM
Hopkins
Paul N
PN
Whitsel
Eric A
EA
Arnett
Donna K
DK
Eckfeldt
John H
JH
Province
Michael A
MA
Ellison
R Curtis
RC
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003327:Coronary Disease / Q000235:genetics* / Q000517:prevention & control; D003430:Cross-Sectional Studies; D004281:Docosahexaenoic Acids / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects*; D002149:Energy Intake; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D012737:Sex Factors; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000517:prevention & control*; D017962:alpha-Linolenic Acid / Q000008:administration & dosage* / Q000378:metabolism
D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids