title: Cigarette Smoking and Carotid Plaque Echodensity in the Northern Manhattan Study.
abstract: BACKGROUND
  We sought to determine the association between cigarette smoking and carotid plaque ultrasound morphology in a multiethnic cohort.
  
  
  METHODS
  We analyzed 1,743 stroke-free participants (mean age 65.5 ± 8.9 years; 60% women; 18% white, 63% Hispanic, 19% black; 14% current and 38% former smokers, 48% never smoked) from the Northern Manhattan Study using an ultrasound index of plaque echodensity, the Gray-Scale Median (GSM). Echolucent plaque (low GSM) represents soft plaque and echodense (high GSM) more calcified plaque. The mean GSM weighted by plaque area for each plaque was calculated for those with multiple plaques. Quintiles of GSM were compared to no plaque. Multinomial logistic regression models were used to assess associations of cigarette smoking with GSM, adjusting for demographics and vascular risk factors.
  
  
  RESULTS
  Among subjects with carotid plaque (58%), the mean GSM scores for quintiles 1-5 were 48, 72, 90, 105, and 128, respectively. Current smokers had over a two fold increased risk of having GSM in quintile 1 (odds ratio (OR) = 2.17; 95% confidence interval (CI), 1.34-3.52), quintile 2 (OR = 2.33; 95% CI, 1.42-3.83), quintile 4 (OR = 2.05; 95% CI, 1.19-3.51), and quintile 5 (OR = 2.13; 95% CI, 1.27-3.56) but not in quintile 3 (OR = 1.18; 95% CI, 0.67-2.10) as compared to never smokers in fully adjusted models. Former smokers had increased risk in quintile 2 (OR = 1.46; 95% CI, 1.00-2.12), quintile 3 (OR = 1.56; 95% CI, 1.09-2.24), quintile 4 (OR = 1.66; 95% CI, 1.13-2.42), and quintile 5 (OR = 1.73; 95% CI, 1.19-2.51), but not in quintile 1 (OR = 1.05; 95% CI, 0.72-1.55).
  
  
  CONCLUSIONS
  A nonlinear, V-shaped-like relationship between current cigarette smoking and plaque echodensity was observed. Former smokers were at the highest risk for plaques in high GSM quintiles. Thus, current smokers were more likely to have either soft or calcified plaques and former smokers were at greater risk of having only echodense plaques when compared to those who have never smoked. Further research is needed to determine if plaque morphology mediates an association between smoking and clinical vascular events.
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, Fla., USA.
authors.forename: Dixon
authors.initials: D
authors.lastname: Yang
authors.forename: Sunil
authors.initials: S
authors.lastname: Iyer
authors.forename: Hannah
authors.initials: H
authors.lastname: Gardener
authors.forename: David
authors.initials: D
authors.lastname: Della-Morte
authors.forename: Milita
authors.initials: M
authors.lastname: Crisby
authors.forename: Chuanhui
authors.initials: C
authors.lastname: Dong
authors.forename: Ken
authors.initials: K
authors.lastname: Cheung
authors.forename: Consuelo
authors.initials: C
authors.lastname: Mora-McLaughlin
authors.forename: Clinton B
authors.initials: CB
authors.lastname: Wright
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Elkind
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Sacco
authors.forename: Tatjana
authors.initials: T
authors.lastname: Rundek
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D044383:Black People; D002339:Carotid Arteries / Q000503:physiopathology*; D002340:Carotid Artery Diseases / Q000150:complications* / Q000175:diagnosis; D016893:Carotid Stenosis / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000150:complications* / Q000175:diagnosis; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D020521:Stroke / Q000150:complications*