title: Gender differences in the effect of weekly working hours on occupational injury risk in the United States         working population.
abstract: OBJECTIVE
  Long working hours can lead to an accumulation in fatigue that may increase worker's risk         of injury. However, it is not known if this association is different for men and women. Our aim was, therefore, to         investigate gender differences in the effect of weekly working hours on occupational injury risk.
  
  
  METHODS
  The US         National Health Interview Survey is a clustered, stratified, cross-sectional sample representative of the US         population, collected using in-household interviews. We pooled seven years of data (2004-2010) comprising 96 915         employed workers. Annualized injury rates per 100 workers were estimated for men and women in categories of weekly         working hours (<30, 31-40, 41-50, >50 hours/week). Additionally, injury risk was predicted using         weighted logistic regression models by weekly working hour categories, stratified by gender, including age, ethnicity,         education, type of pay, occupation, body mass index, usual sleep duration, and psychological distress as covariates.
  
  
  RESULTS
  Of 96 915 workers, 705 (0.75%) reported an injury in the last 3 months. Injury rates were higher among men and         increased with increasing working hours for both genders. However, results of the adjusted logistic regression model         indicated an interactive effect of working hours and gender on injury risk [odds ratio (OR) 1.02, 95% confidence         interval (95% CI) 1.00-1.03). Injury risk increased among women working 41-50 hours/week (OR 1.51, 95% CI         1.03-2.21) and >50 hours/week (OR 1.69, 95% CI 1.06-2.70) compared to 31-40 hours/week but not         among men.
  
  
  CONCLUSIONS
  The findings indicate an increase in injury risk with increasing working hours among women but         not men.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Landmark Center, 401 Park Drive, Boston, MA 02215, USA. awirtz@hsph.harvard.edu
authors.forename: Anna
authors.initials: A
authors.lastname: Wirtz
authors.forename: David A
authors.initials: DA
authors.lastname: Lombardi
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Willetts
authors.forename: Simon
authors.initials: S
authors.lastname: Folkard
authors.forename: David C
authors.initials: DC
authors.lastname: Christiani
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060051:Occupational Injuries / Q000453:epidemiology*; D012307:Risk Factors; D012737:Sex Factors; D014481:United States / Q000453:epidemiology