Traditional Risk Factors Are Not Major Contributors to the Variance in Carotid Intima-Media Thickness

• Published in: Stroke (1970) Vol. 44; no. 8; pp. 2101 - 2108
• Main Authors: Rundek, Tatjana, Blanton, Susan H, Bartels, Susanne, Dong, Chuanhui, Raval, Ami, Demmer, Ryan T, Cabral, Digna, Elkind, Mitchell S.V, Sacco, Ralph L, Desvarieux, Moise
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Heart Association, Inc 01-08-2013; Lippincott Williams & Wilkins
• Subjects: Age Factors; Aged; Atherosclerosis (general aspects, experimental research); Atherosclerosis - blood; Atherosclerosis - diagnostic imaging; Atherosclerosis - urine; Biological and medical sciences; Biomarkers; Blood and lymphatic vessels; Blood Glucose - metabolism; Cardiology. Vascular system; Carotid Arteries - diagnostic imaging; Carotid Intima-Media Thickness - instrumentation; Cholesterol, LDL - metabolism; Female; Glomerular Filtration Rate - physiology; Humans; Linear Models; Male; Medical sciences; Models, Statistical; Neurology; Risk Factors; Sex Factors; Smoking - adverse effects; Smoking - blood; Smoking - pathology; Vascular diseases and vascular malformations of the nervous system; Stroke; Nervous system diseases; risk factors; Cardiovascular disease; carotid ultrasound; carotid intima-media thickness; Cerebral disorder; Vascular disease; Carotid; Central nervous system disease; Risk factor; Ultrasound; Cerebrovascular disease
• DOI: 10.1161/STROKEAHA.111.000745
• EISSN: 1524-4628
• ISSN: 0039-2499

BACKGROUND AND PURPOSE—Carotid intima-media thickness (cIMT) was a widely accepted ultrasound marker of subclinical atherosclerosis in the past. Although traditional risk factors may explain ≈50% of the variance in plaque burden, they may not explain such a high proportion of the variance in IMT, especially when measured in plaque-freel ocations. We aimed this study to identify individuals with cIMT unexplained by traditional risk factors for future environmental and genetic research.
METHODS—As part of the Northern Manhattan Study, 1790 stroke-free individuals (mean age, 69±9 years; 60% women; 61% Hispanic; 19% black; 18% white) were assessed for cIMT using B-mode carotid ultrasound. Multiple linear regression models were evaluated(1) incorporating prespecified traditional risk factors; and (2) including less traditional factors, such as inflammation biomarkers, adiponectin, homocysteine, and kidney function. Standardized cIMT residual scores were constructed to select individuals with unexplained cIMT.
RESULTS—Mean total cIMT was 0.92±0.09 mm. The traditional model explained 11% of the variance in cIMT. Age (7%), male sex (3%), glucose (<1%), pack-years of smoking (<1%), and low-density lipoprotein cholesterol (<1%) were significant contributing factors. The model, including inflammatory biomarkers, explained 16% of the variance in cIMT. Adiponectin was the only additional significant contributor to the variance in cIMT. We identified 358 individuals (20%) with cIMT unexplained by the investigated risk factors.
CONCLUSIONS—Vascular risk factors explain only a small proportion of variance in cIMT. Identification of novel genetic and environmental factors underlying unexplained subclinical atherosclerosis is of utmost importance for future effective prevention of vascular disease.