title: Progression of subclinical coronary atherosclerosis: does obesity make a difference?
abstract: BACKGROUND
  Obesity is associated with coronary artery calcification (CAC), a marker of the presence and extent of subclinical coronary atherosclerosis. Obesity adds incremental information in identifying those at higher risk of coronary heart disease to traditional risk factor assessment. The present study examined associations between obesity measures and progression of CAC in those at higher (> or =10%) and lower (<10%) 10-year coronary heart disease risk according to the Framingham risk equation.
  
  
  RESULTS
  In this study, 443 asymptomatic white individuals >30 years of age (243 men) had baseline and follow-up CAC measurements an average of 8.9 years apart. Multivariable linear regression models were fit to determine associations of obesity measures at baseline with progression of CAC defined as log(e) of the difference between follow-up and baseline CAC area plus 1 divided by time (in years) between examinations, adjusting for baseline CAC quantity, age, sex, baseline hypertension status, and baseline cholesterol level. Among 329 participants (74.3%) in the lower-risk group, waist circumference (P=0.024), waist-to-hip ratio (P<0.001), body mass index (P=0.036), and being overweight compared with being underweight or of normal weight (P=0.008) were each significantly positively associated with progression of CAC. Among those at higher coronary heart disease risk, no baseline obesity measures were associated with CAC progression.
  
  
  CONCLUSIONS
  Various measures of obesity were associated with increased progression of CAC in those at lower risk of coronary heart disease. Future studies examining the effectiveness of weight reduction strategies in reducing CAC progression among those with an otherwise favorable risk factor profile may be warranted.
authors.affiliation: Department of Epidemiology, University of Michigan, 611 Church St, Ann Arbor, MI 48104-3028, USA.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Cassidy
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Bielak
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Patrick F
authors.initials: PF
authors.lastname: Sheedy
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Turner
authors.forename: Jerome F
authors.initials: JF
authors.lastname: Breen
authors.forename: Philip A
authors.initials: PA
authors.lastname: Araoz
authors.forename: Iftikhar J
authors.initials: IJ
authors.lastname: Kullo
authors.forename: Xihong
authors.initials: X
authors.lastname: Lin
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Peyser
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001837:Body Weights and Measures; D003324:Coronary Artery Disease / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology; D003625:Data Collection; D018450:Disease Progression; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D049629:Waist-Hip Ratio