Abstract P408: Plasma Alkylresorcinol, A Biomarker of Whole-Grain Intake, Is Not Associated With Progression of Coronary Artery Atherosclerosis In Postmenopausal Women With Coronary Artery Disease

Abstract

Background: Higher whole-grain intake has been associated with lower risk of cardiovascular disease in prospective observational studies. Few observational studies have incorporated biomarkers of whole-grain intake to confirm self-reported diet-disease associations. Plasma alkylresorcinols (AR) have been used as biomarkers for whole-grain wheat and rye intake. Objective: To assess the relationship between plasma AR concentrations and atherosclerotic progression over a 3-y period. Methods: Plasma AR concentrations were measured by gas chromatography mass spectrometry in baseline samples from 163 post-menopausal women (aged 49-78 y; median BMI: 29.0 kg/m2) with established coronary artery disease (CAD) who participated in the Estrogen Replacement and Atherosclerosis Study (enrolled 1995-1996) and had baseline food frequency questionnaire (FFQ), baseline and follow-up angiography measures, and complete covariate data. Dietary fiber intake was estimated by FFQ and energy-adjusted. Atherosclerosis progression, defined as change in mean minimum coronary artery diameter (MCAD, mm) and change in percent stenosis (%ST), was regressed on plasma AR in mixed models accounting for within-person correlations of coronary segments, and adjusted for the baseline measure, treatment allocation, clinic, age, race, BMI and follow-up time. Results: Median plasma AR was 16.1 nmol/L (interquartile range: 10.9-25.7). Over 3.1±0.7 years of follow-up, MCAD decreased by approximately 0.09±0.02 mm, while %ST increased by approximately 3.2±0.7%. No significant association was observed between AR and change in MCAD or %ST: a 10% increment in AR was associated with a -0.0002±0.0008 mm (P=0.76) change in MCAD and a 0.008±0.03 change in %ST (P=0.79). Further adjustment for lifestyle and risk factors did not materially change these results. As expected, AR correlated with FFQ- derived intake of cereal fiber (Spearman r=0.27, P<0.001) and whole grains (Spearman r=0.28, P<0.001). Of note, this cohort reported low whole-grain and cereal fiber intakes (9.5 servings/wk and 5.3 g/d, respectively). Conclusions: Plasma AR concentrations were not significantly associated with coronary narrowing over a 3-y period in postmenopausal women with CAD. We cannot rule out that large measurement errors in the biomarker, owing to low intake and short half-life may explain the findings.