Abstract P220: Exposure to Secondhand Smoke and the Risk of Stroke
Background: Stroke is a leading cause of death worldwide, and is a major public health concern in terms of morbidity, mortality, economic costs, and loss of productivity. While exposure to secondhand smoke (SHS) is a risk factor for cardiovascular disease, associations of SHS with risk of stroke have been inconsistent.
Hypothesis: We investigated the hypotheses that SHS exposure is associated with increased incidence of stroke and stroke subtypes (ischemic stroke and hemorrhagic stroke) among non-smokers, including never and former smokers.
Methods: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled a U.S. population sample of 30,239 Caucasian and African-American men and women aged >=45 years in 2003-7 and is following them for stroke outcomes. We calculated the hazard ratio (HR) of stroke among non-smokers with SHS exposure using Cox proportional hazard models.
Results: The cohort, without prevalent smoking, stroke and TIA (n=21,743), included 62% Caucasians and 38% African-Americans, with 55% females. Twenty-three percent reported SHS exposure the year prior to enrollment, and these individuals were more likely to be younger, African-American, male (all p<0.001), and have higher C-reactive protein (CRP) and white blood count (WBC) (p<0.05) compared to those not exposed. SHS exposure was associated with a 31% increased risk of any stroke event after adjustment for demographic, socioeconomic, and behavioral factors (Table 1). The association was seen only in ischemic, but not hemorrhagic stroke. Associations were slightly diminished after adjusting for traditional stroke risk factors, and markedly attenuated to the null after further addition of inflammation markers.
Conclusions: SHS exposure was not related to stroke after accounting for inflammation markers. Further research is needed to confirm these findings.
Author Disclosures: A.M. Malek: None. L.A. McClure: None. M. Cushman: None. D.T. Lackland: None.
- © 2014 by American Heart Association, Inc.