title: Controlling for apolipoprotein A-I concentrations changes the inverse direction of the relationship between high HDL-C concentration and a measure of pre-clinical atherosclerosis.
abstract: BACKGROUND
  The independent effect of high density lipoprotein cholesterol (HDL-C) concentration to confer cardiovascular disease protection has been questioned. We investigated whether the inverse association between HDL-C concentration and a measure of preclinical atherosclerosis was modified by other risk factors.
  
  
  METHODS
  Cross-sectional data were analysed from an occupational cohort of 12,031 men who had measurements of cardiovascular risk factors and a cardiac computed tomography (CT) estimation of coronary artery calcium (CAC) score, a measure of pre-clinical atherosclerosis. Logistic regression was used to describe associations between both HDL-C and Apo-A-I concentrations and their ratio as exposures, and CAC scores > 0, ≥ 20 and ≥ 100, as outcomes.
  
  
  RESULTS
  1351 (11.2%), 665 (5.5%) and 230 (1.9%) of participants had a CAC score > 0, ≥ 20 and ≥ 100, respectively. Adjusting for age, glucose, triglyceride, LDL-C, systolic blood pressure, waist circumference, prior cerebrovascular accident, prior coronary artery disease, prior hypertension, alcohol consumption, smoking status and exercise, a negative association existed between HDL-C and CAC score. (E.g. odds ratio (OR) for top compared to bottom HDL-C quartile for CAC > 0 = 0.78 [95%CI 0.64, 0.94], p = 0.01). Further adjustment for Apo A-I changed the direction of the association between HDL-C and CAC score > 0 (OR for top compared to bottom quartiles 1.61 [95%CI 1.18, 2.21], p = 0.003). Sensitivity analyses showed that point estimates for ORs were very similar regardless of CAC score threshold (CAC > 0, ≥ 20 and ≥ 100).
  
  
  CONCLUSIONS
  Controlling for Apo A-I concentrations changes the inverse direction of relationship between high HDL-C concentration and a measure of pre-clinical atherosclerosis.
authors.affiliation: Division of Cardiology, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, #108, Pyung Dong, Jongro-Ku, Seoul 110-746, Republic of Korea. Electronic address: kcmd.sung@samsung.com.
authors.forename: Ki-Chul
authors.initials: KC
authors.lastname: Sung
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Wild
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Byrne
mesh_terms: D000328:Adult; D000368:Aged; D016632:Apolipoprotein A-I / Q000097:blood*; D050197:Atherosclerosis / Q000097:blood / Q000175:diagnosis*; D001794:Blood Pressure; D002114:Calcinosis / Q000175:diagnosis; D002318:Cardiovascular Diseases / Q000097:blood / Q000175:diagnosis; D008076:Cholesterol, HDL / Q000097:blood*; D015331:Cohort Studies; D003331:Coronary Vessels / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012044:Regression Analysis; D056910:Republic of Korea; D012306:Risk; D012720:Severity of Illness Index
chemical_list: D016632:Apolipoprotein A-I; D008076:Cholesterol, HDL
keywords: Apo A-I; Apolipoprotein A-I; Atherosclerosis; BMI; CAC; CETP; CVD; Cardio-metabolic risk factors; Cardiovascular disease (CVD); Coronary artery calcium; Coronary artery calcium (CAC) score; DBP; HDL-C; MetS; SBP; TG; apolipoprotein A-I; body mass index; cardiovascular disease; cholesterol ester transfer protein; diastolic blood pressure; high density lipoprotein cholesterol; metabolic syndrome; systolic blood pressure; triglyceride