ORLANDO, Fla. — Higher levels of exhaled carbon monoxide were associated with increased risk for stroke and transient ischemic attack and greater burden of subclinical cerebrovascular disease, according to new data.
Matthew G. Nayor, MD, from Brigham and Women’s Hospital, and colleagues analyzed 3,313 participants of the Framingham Offspring Study with no evidence of stroke or TIA at baseline. All participants had exhaled carbon monoxide measured and were stratified into tertiles based on concentration of exhaled carbon monoxide (≤ 4 parts per million [ppm]; > 4 ppm to < 5 ppm; ≥ 5 ppm). In addition, 1,982 of participants had brain MRI imaging performed.
Matthew G. Nayor
The researchers performed one analysis on the entire cohort, and another on the 2,819 nonsmokers only.
Mean follow-up was 12.9 years.
After adjustment for age and sex, participants in the highest tertile of exhaled carbon monoxide had lower total cerebral brain volume, higher volume of hyperintensive white matter and a higher rate of silent cerebral infarct (P < .05), Nayor and colleagues reported.
The associations with lower total cerebral brain volume and higher volume of hyperintensive white matter persisted after exclusion of smokers, and the association with higher volume of hyperintensive white matter remained after multivariable adjustment (P = .04).
Compared with the lowest tertile, participants in the middle tertile (HR = 1.67; 95% CI, 1.2-2.32) and the highest tertile (HR = 1.97; 95% CI, 1.41-2.76) had increased risk for incident stroke or TIA after adjustment for age and sex. This was also true after exclusion of smokers (middle tertile HR = 1.69; 95% CI, 1.21-2.35; highest tertile HR = 1.63; 95% CI, 1.09-2.44).
When Nayor and colleagues adjusted for vascular risk factors, the results were partly attenuated, but were maintained when further adjusting for B-type natriuretic peptide and C-reactive protein levels.
“Further investigation is necessary to explore the biological mechanisms linking [carbon monoxide] with stroke,” Nayor and colleagues wrote in an abstract. – by Erik Swain
Nayor MG, et al. Abstract 199. Presented at: American Heart Association Scientific Sessions; Nov. 7-11, 2015; Orlando, Fla.
Disclosure: Nayor reports no relevant financial disclosures.