title: Herpes zoster as a risk factor for stroke and TIA: a retrospective cohort study in the UK.
abstract: OBJECTIVE
  Stroke and TIA are recognized complications of acute herpes zoster (HZ). Herein, we evaluate HZ as a risk factor for cerebrovascular disease (stroke and TIA) and myocardial infarction (MI) in a UK population cohort.
  
  
  METHODS
  A retrospective cohort of 106,601 HZ cases and 213,202 controls, matched for age, sex, and general practice, was identified from the THIN (The Health Improvement Network) general practice database. Cox proportional hazard models were used to examine the risks of stroke, TIA, and MI in cases and controls, adjusted for vascular risk factors, including body mass index >30 kg/m(2), smoking, cholesterol >6.2 mmol/L, hypertension, diabetes, ischemic heart disease, atrial fibrillation, intermittent arterial claudication, carotid stenosis, and valvular heart disease, over 24 (median 6.3) years after HZ infection.
  
  
  RESULTS
  Risk factors for vascular disease were significantly increased in cases of HZ compared with controls. Adjusted hazard ratios for TIA and MI but not stroke were increased in all patients with HZ (adjusted hazard ratios [95% confidence intervals]: 1.15 [1.09-1.21] and 1.10 [1.05-1.16], respectively). However, stroke, TIA, and MI were increased in cases whose HZ occurred when they were younger than 40 years (adjusted hazard ratios [95% confidence intervals]: 1.74 [1.13-2.66], 2.42 [1.34-4.36], and 1.49 [1.04-2.15], respectively). Subjects younger than 40 years were significantly less likely to be asked about vascular risk factors compared with older patients (p < 0.001).
  
  
  CONCLUSIONS
  HZ is an independent risk factor for vascular disease in the UK population, particularly for stroke, TIA, and MI in subjects affected before the age of 40 years. In older subjects, better ascertainment of vascular risk factors and earlier intervention may explain the reduction in risk of stroke after HZ infection.
authors.affiliation: From the Division of Infection and Immunity (J.B.), and Institute of Neurology (M.M.B.), University College London, UK; and Amaris (M.P., A.G.). j.breuer@ucl.ac.uk.
authors.forename: Judith
authors.initials: J
authors.lastname: Breuer
authors.affiliation: From the Division of Infection and Immunity (J.B.), and Institute of Neurology (M.M.B.), University College London, UK; and Amaris (M.P., A.G.).
authors.forename: Maud
authors.initials: M
authors.lastname: Pacou
authors.affiliation: From the Division of Infection and Immunity (J.B.), and Institute of Neurology (M.M.B.), University College London, UK; and Amaris (M.P., A.G.).
authors.forename: Aline
authors.initials: A
authors.lastname: Gautier
authors.affiliation: From the Division of Infection and Immunity (J.B.), and Institute of Neurology (M.M.B.), University College London, UK; and Amaris (M.P., A.G.).
authors.forename: Martin M
authors.initials: MM
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006562:Herpes Zoster / Q000150:complications*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000453:epidemiology / Q000209:etiology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D015995:Prevalence; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000209:etiology*; D016019:Survival Analysis; D006113:United Kingdom / Q000453:epidemiology