title: Secondhand Smoke Exposure and Stroke: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.
abstract: BACKGROUND
  Stroke is a major public health concern worldwide given the associated morbidity and mortality. Smoking is a risk factor for stroke, but the relationship between secondhand smoke (SHS) exposure and stroke has been inconsistent to date. The aim of the current study was to examine the association of SHS exposure and risk of stroke and its subtypes (ischemic and hemorrhagic stroke) among nonsmokers.
  
  
  METHODS
  Demographic and clinical characteristics were compared by SHS exposure status for African American and white nonsmokers aged ≥45 years in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study in 2014. Hazard ratios (HRs) and corresponding 95% CIs were calculated by Cox proportional hazards models to assess the relationship between SHS exposure and stroke risk.
  
  
  RESULTS
  Of the 21,743 participants (38% African American, 45% male), SHS exposure in the past year was reported by 23%. Compared with those without SHS exposure, exposed participants were more likely to be female, white, younger, and reside with a smoker (all p<0.001). A total of 428 incident strokes were observed from April 2003 to March 2012 during a mean follow-up of 5.6 years. The risk of overall stroke was increased 30% among those with SHS exposure after adjustment for other stroke risk factors (95% CI=2%, 67%). This relationship appeared to be driven by ischemic strokes.
  
  
  CONCLUSIONS
  SHS exposure is independently associated with an increased risk of stroke. Future studies are needed to confirm these findings and examine the role of long-term effects of SHS exposure on stroke outcomes.
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, South Carolina. Electronic address: malek@musc.edu.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Malek
authors.affiliation: Departments of Medicine and Pathology, University of Vermont, Colchester, Vermont.
authors.forename: Mary
authors.initials: M
authors.lastname: Cushman
authors.affiliation: Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina;
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Lackland
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: George
authors.initials: G
authors.lastname: Howard
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: McClure
mesh_terms: D001741:Black or African American; D000368:Aged; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D057566:Self Report; D020521:Stroke / Q000139:chemically induced*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D044465:White People
chemical_list: D014028:Tobacco Smoke Pollution