title: Interleukin-18 levels are not associated with subclinical carotid atherosclerosis in a community population. The Perth Carotid Ultrasound Disease Assessment Study (CUDAS).
abstract: Interleukin (IL)-18 is a novel proinflammatory cytokine that plays a central role in innate and acquired immunity, making it a likely inflammatory candidate in atherosclerosis. We investigated whether circulating IL-18 levels were associated with subclinical atherosclerosis in a community population. Carotid intimal medial thickness (IMT) and carotid plaques were assessed in a cross-sectional study of 1111 randomly selected community subjects, aged 27-77 years. Baseline levels of IL-18, IL-6, high sensitive CRP (hsCRP), fibrinogen and white cell counts were measured along with conventional cardiovascular risk factors. Men had higher mean IL-18 levels than women (P<0.0001). Spearman rank correlations (r(s)) showed that IL-18 was weakly correlated with all inflammatory markers in the whole population (r(s) between 0.11 and 0.23, all P<0.001). IL-18 was also correlated with conventional risk factors including waist-hip ratio, BMI, blood pressure, triglycerides, HDL (inversely) and pack-years smoking (r(s) between 0.18 and 0.39, all P<0.001) but not with LDL-cholesterol. Independent predictors of IL-18 concentrations were waist-hip ratio, HDL, IL-6, hsCRP and hypertension. There was a positive univariate association of IL-18 levels with carotid IMT (P<0.001) and plaque prevalence (P<0.001) but no residual association after adjustment for conventional risk factors (both P>0.05). In a cross-sectional community population, IL-18 levels were related to traditional risk factors and inflammatory markers but were not independently associated with subclinical carotid atherosclerosis.
authors.affiliation: Clinical Biochemistry, PathWest, QEII Medical Centre, Perth, WA, Australia.
authors.forename: Caroline M L
authors.initials: CM
authors.lastname: Chapman
authors.forename: Brendan M
authors.initials: BM
authors.lastname: McQuillan
authors.forename: John P
authors.initials: JP
authors.lastname: Beilby
authors.forename: Peter L
authors.initials: PL
authors.lastname: Thompson
authors.forename: Joseph
authors.initials: J
authors.lastname: Hung
mesh_terms: D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D020382:Interleukin-18 / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D014463:Ultrasonography; D014904:Western Australia / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D020382:Interleukin-18; D015850:Interleukin-6; D016209:Interleukin-8; D005340:Fibrinogen; D002097:C-Reactive Protein