title: Hormonal contraception among electronic cigarette users and cardiovascular risk: a systematic review.
abstract: BACKGROUND
  Women who use combined hormonal contraceptives and cigarettes have an increased risk for cardiovascular (CV) events. We reviewed the literature to determine whether women who use hormonal contraceptives (HC) and electronic cigarettes (e-cigarettes) also have an increased risk.
  
  
  METHODS
  Systematic review.
  
  
  METHODS
  We searched for articles reporting myocardial infarction (MI), stroke, venous thromboembolism, peripheral arterial disease or changes to CV markers in women using e-cigarettes and HC. We also searched for indirect evidence, such as CV outcomes among e-cigarette users in the general population and among HC users exposed to nicotine, propylene glycol or glycerol.
  
  
  RESULTS
  No articles reported on outcomes among e-cigarette users using HC. Among the general population, 13 articles reported on heart rate or blood pressure after e-cigarette use. These markers generally remained normal, even when significant changes were observed. In three studies, changes were less pronounced after e-cigarette use than cigarette use. One MI was reported among 1012 people exposed to e-cigarettes in these studies. One article on nicotine and HC exposure found both exposures to be significantly associated with acute changes to heart rate, though mean heart rate remained normal. No articles on propylene glycol or glycerol and HC exposure were identified.
  
  
  CONCLUSIONS
  We identified no evidence on CV outcomes among e-cigarette users using HC. Limited data reporting mostly acute outcomes suggested that CV events are rare among e-cigarette users in the general population and that e-cigarettes may affect heart rate and blood pressure less than conventional cigarettes. There is a need for research assessing joint HC and e-cigarette exposure on clinical CV outcomes.
authors.affiliation: Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA, USA. Electronic address: heriley@emory.edu.
authors.forename: Halley E M
authors.initials: HE
authors.lastname: Riley
authors.affiliation: Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Berry-Bibee
authors.affiliation: Office on Smoking and Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Lucinda J
authors.initials: LJ
authors.lastname: England
authors.affiliation: Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Jamieson
authors.affiliation: Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Polly A
authors.initials: PA
authors.lastname: Marchbanks
authors.affiliation: Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Curtis
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003271:Contraceptive Agents, Female / Q000009:adverse effects*; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate; D006728:Hormones / Q000009:adverse effects; D006801:Humans
chemical_list: D003271:Contraceptive Agents, Female; D006728:Hormones
keywords: Cardiovascular disease; Electronic cigarettes; Glycerol; Hormonal contraceptives; Nicotine; Propylene glycol