title: A prospective study of caffeine intake and risk of incident tinnitus.
abstract: BACKGROUND
  Caffeine is a commonly consumed substance that has been thought to play a role in the development of tinnitus, but prospective data are lacking. We prospectively evaluated the association between caffeine intake and self-reported tinnitus in a female cohort.
  
  
  METHODS
  Participants were 65,085 women in the Nurses' Health Study II, aged 30 to 44 years and without tinnitus at baseline in 1991, who completed questionnaires about lifestyle and medical history every 2 years and food frequency questionnaires every 4 years. Information on self-reported tinnitus and date of onset was obtained from the 2009 questionnaire, with cases defined as those reporting experiencing symptoms "a few days/week" or "daily." Multivariable adjusted hazard ratios were calculated using Cox proportional hazards regression models.
  
  
  RESULTS
  At baseline, the mean age of the cohort was 36.3 years and the mean caffeine intake was 242.3 mg/d. After 18 years of follow-up, 5289 incident cases of tinnitus were reported. There was a significant inverse association between caffeine intake and the incidence of tinnitus. Compared with women with caffeine intake less than 150 mg/d (150 mg corresponds to ∼ one 8-ounce cup of coffee), the multivariable adjusted hazard ratios were 0.85 (95% confidence interval, 0.76-0.95) for those who consumed 450 to 599 mg/d and 0.79 (0.68-0.91) for those who consumed 600 mg/d or more.
  
  
  CONCLUSIONS
  In this prospective study, higher caffeine intake was associated with a lower risk of incident tinnitus in women.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada. Electronic address: jglicksm@uwo.ca.
authors.forename: Jordan T
authors.initials: JT
authors.lastname: Glicksman
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Mass.
authors.forename: Sharon G
authors.initials: SG
authors.lastname: Curhan
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Mass; Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Mass; Department of Epidemiology, Harvard School of Public Health, Boston, Mass.
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
mesh_terms: D000328:Adult; D001628:Beverages / Q000009:adverse effects; D002110:Caffeine / Q000009:adverse effects*; D003625:Data Collection; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014012:Tinnitus / Q000139:chemically induced*
chemical_list: D002110:Caffeine
keywords: Caffeine; Epidemiology; Tinnitus