title: Reactivated herpes simplex infection increases the risk of Alzheimer's disease.
abstract: BACKGROUND
  Previous studies have suggested a link between herpes simplex virus (HSV) type 1 and the development of Alzheimer's disease (AD).
  
  
  METHODS
  The present analysis included 3432 persons (53.9% women, mean age at inclusion 62.7 ± 14.4 years) with a mean follow-up time of 11.3 years. The number of incident AD cases was 245. Serum samples were analyzed for anti-HSV antibodies (immunoglobulin (Ig)G and IgM) by enzyme-linked immunosorbent assays.
  
  
  RESULTS
  The presence of anti-HSV IgG antibodies was not associated with an increased risk for AD, controlled for age and sex (hazard ratio, HR, 0.993, P = .979). However, the presence of anti-HSV IgM at baseline was associated with an increased risk of developing AD (HR 1.959, P = .012).
  
  
  CONCLUSIONS
  Positivity for anti-HSV IgM, a sign of reactivated infection, was found to almost double the risk for AD, whereas the presence of anti-HSV IgG antibodies did not affect the risk.
authors.affiliation: Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University, Umeå, Sweden. Electronic address: hugo.lovheim@germed.umu.se.
authors.forename: Hugo
authors.initials: H
authors.lastname: Lövheim
authors.affiliation: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gilthorpe
authors.affiliation: Department of Clinical Sciences, Psychiatry, Umeå University, Umeå, Sweden.
authors.forename: Rolf
authors.initials: R
authors.lastname: Adolfsson
authors.affiliation: Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden; Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
authors.forename: Lars-Göran
authors.initials: LG
authors.lastname: Nilsson
authors.affiliation: Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Elgh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000821:virology*; D000914:Antibodies, Viral / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006561:Herpes Simplex / Q000453:epidemiology* / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000276:immunology / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D014775:Virus Activation
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Alzheimer's disease; Cohort study; Dementia; HSV; Herpes; Herpes simplex