title: Association of high resting end tidal CO2 with carotid artery thickness in women, but not men.
abstract: BACKGROUND
  A previous study found high resting end tidal CO2 (PetCO2) to be an independent determinant of systolic blood pressure in women, but not men. The present study investigates the association of PetCO2 with the common carotid artery intima-media thickness (IMT) and wall-to-lumen (W/L) ratio in a sample of normotensive men and women.
  
  
  METHODS
  Resting PetCO2 of 188 healthy volunteers, including 88 men and 100 women, in the Baltimore Longitudinal Study on Aging was monitored continuously for 25 min via a respiratory gas monitor. At another session, carotid artery IMT was determined via high-resolution B-mode carotid ultrasonography. The ratio of IMT to carotid artery diameter was calculated as W/L ratio. Resting blood pressure was determined oscillometrically every 5 min for 20 min during each session.
  
  
  RESULTS
  Univariate associations of PetCO2 with systolic blood pressure (SBP) (P< 001), IMT (P< 001) and W/L ratio (P< 001) were significant in women, but not men. Multiple regression analyses showed that high resting PetCO2 was a predictor of SBP (P < 01), IMT (P< 01) and W/L ratio (P< 01) in women, independent of age, body mass index and SBP. For men, age (P < 001) and SBP (P < 01) were independent predictors of carotid IMT, while age (P< 001) was the only independent predictor of W/L ratio in men.
  
  
  CONCLUSIONS
  This study indicates that PetCO2 can play a role in cardiovascular structure, as well as function, in women, and that the relationship is independent of the association of PetCO2 with blood pressure.
authors: Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, Maryland 21224, USA.
authors: D E
authors: DE
authors: Anderson
authors: A
authors: A
authors: Scuteri
authors: E J
authors: EJ
authors: Metter
authors: M A
authors: MA
authors: Chesney
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000502:physiology*; D017536:Carotid Artery, Common / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012119:Respiration; D012727:Sex Characteristics; D014463:Ultrasonography
chemical_list: D002245:Carbon Dioxide