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Human and Clinical Nutrition
Abbreviations: CCA, common carotid artery; FS, full food pattern score; ICA, internal carotid artery; IMT, intimal medial thickness; IRAS, Insulin Resistance Atherosclerosis Study; PAI-1, plasminogen activator inhibitor 1; RRR, reduced rank regression; SI, insulin sensitivity
Reduced rank regression (RRR) is increasingly recognised as a promising method in dietary pattern research. Food intake patterns are identified among food groups by concurrently utilising data on a set of response variables, ideally biomarkers, selected because of known associations with the disease of interest(1). RRR can be particularly powerful if the response factors are highly predictive biomarkers.
Interestingly, only a few studies to date have applied RRR to the evaluation of dietary predictors of CHD, even though this field would seem particularly fruitful given the well-established characterisation of biomarker risk factors for CHD. In one such endeavour, homocysteine metabolism-related biomarkers were utilised and the investigators found a strong inverse association between a healthful food intake pattern and CHD(2). Two studies utilising either a range of biomarkers including lipids, C-reactive protein and C-peptide(3) or focusing on lipid levels(4) identified largely detrimental food intake patterns strongly associated with CHD.
To the best of our knowledge, neither prospective studies employing RRR have been conducted that have used multiple markers of inflammation nor has any study focused on markers of subclinical atherosclerosis. Carotid intimal medial thickness (IMT) is now an established marker for early atherosclerosis and has been shown to be a strong predictor of future vascular events(5). A 1 sd common carotid artery (CCA) IMT difference has been associated with a relative risk of myocardial infarction of 1·26, or in absolute terms, a 0·10 mm CCA IMT difference has been associated with a relative risk of 1·15(5). Furthermore, there is now consistent evidence that fibrinogen(6) is a risk factor for CVD. The association of plasminogen activator inhibitor 1 (PAI-1) with CHD risk is suggestive, but likely more complex(7,8).
The purpose of the present study was to identify RRR-determined food intake patterns that affect inflammatory biomarkers and to evaluate their association with...