title: Body mass index, waist circumference, physical activity, and risk of hearing loss in women.
abstract: BACKGROUND
  Acquired hearing loss is highly prevalent, but prospective data on potentially modifiable risk factors are limited. In cross-sectional studies, higher body mass index (BMI), larger waist circumference, and lower physical activity have been associated with poorer hearing, but these have not been examined prospectively.
  
  
  METHODS
  We examined the independent associations between BMI, waist circumference, and physical activity, and self-reported hearing loss in 68,421 women in the Nurses' Health Study II from 1989 to 2009. Baseline and updated information on BMI, waist circumference, and physical activity was obtained from biennial questionnaires.
  
  
  RESULTS
  After more than 1.1 million person-years of follow-up, 11,286 cases of hearing loss were reported to have occurred. Higher BMI and larger waist circumference were associated with increased risk of hearing loss. Compared with women with BMI <25 kg/m(2), the multivariate-adjusted relative risk (RR) for women with BMI ≥ 40 was 1.25 (95% confidence interval [CI], 1.14-1.37). Compared with women with waist circumference <71 cm, the multivariate-adjusted RR for waist circumference >88 cm was 1.27 (95% CI, 1.17-1.38). Higher physical activity was related inversely to risk; compared with women in the lowest quintile of physical activity, the multivariate-adjusted RR for women in the highest quintile was 0.83 (95% CI, 0.78-0.88). Walking 2 hours per week or more was associated inversely with risk. Simultaneous adjustment for BMI, waist circumference, and physical activity slightly attenuated the associations but they remained statistically significant.
  
  
  CONCLUSIONS
  Higher BMI and larger waist circumference are associated with increased risk, and higher physical activity is associated with reduced risk of hearing loss in women. These findings provide evidence that maintaining healthy weight and staying physically active, potentially modifiable lifestyle factors, may help reduce the risk of hearing loss.
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Mass. Electronic address: SCurhan@partners.org.
authors.forename: Sharon G
authors.initials: SG
authors.lastname: Curhan
authors.forename: Roland
authors.initials: R
authors.lastname: Eavey
authors.forename: Molin
authors.initials: M
authors.lastname: Wang
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D034381:Hearing Loss / Q000209:etiology*; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D015999:Multivariate Analysis; D012307:Risk Factors; D055105:Waist Circumference
keywords: Body mass index; Epidemiology; Hearing loss; Physical activity; Prospective study; Waist circumference