title: Working hours and self-rated health over 7 years: gender differences in a Korean longitudinal study.
abstract: BACKGROUND
  To investigate the association between long working hours and self-rated health (SRH), examining the roles of potential confounding and mediating factors, such as job characteristics.
  
  
  METHODS
  Data were pooled from seven waves (2005-2011) of the Korean Labour and Income Panel Study. A total of 1578 workers who consecutively participated in all seven study years were available for analysis. A generalized estimating equation for repeated measures with binary outcome was used to examine the association between working hours (five categories; 20-35, 36-40, 41-52, 53-68 and ≥ 69 h) and SRH (two categories; poor and good health), considering possible confounders and serial correlation.
  
  
  RESULTS
  Associations between working hours and SRH were observed among women, but only for the category of the shortest working hours among men. The associations with the category of shortest working hours among men and women disappeared after adjustment for socioeconomic factors. Among women, though not men, working longer than standard hours (36-40 h) showed a linear association with poor health; OR = 1.41 (95% CI = 1.08-1.84) for 52-68 working hours and OR = 2.11 (95% CI = 1.42-3.12) for ≥ 69 working hours. This association persisted after serial adjustments. However, it was substantially attenuated with the addition of socioeconomic factors (e.g., OR = 1.66 (95% CI = 1.07-2.57)) but only slightly attenuated with further adjustment for behavioural factors (e.g., OR = 1.63 (95% CI = 1.05-2.53)). The associations with job satisfaction were significant for men and women.
  
  
  CONCLUSIONS
  The worsening of SRH with increasing working hours only among women suggests that female workers are more vulnerable to long working hours because of family responsibilities in addition to their workload.
authors.affiliation: Department of Occupational and Environmental Health, Graduate School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, South Korea. 0361pt@hanmail.net.|Department of Occupational and Environmental Medicine, Konkuk University Chungju Hospital, 82 Gukweondae-ro Chungju, Chungbuk, South Korea. 0361pt@hanmail.net.
authors.forename: Seong-Sik
authors.initials: SS
authors.lastname: Cho
authors.affiliation: Department of Preventive Medicine, School of Medicine, Eulji University, 143-5, Yongdu-dong, Jung-gu, Daejeon, South Korea. myungki@eulji.ac.kr.
authors.forename: Myung
authors.initials: M
authors.lastname: Ki
authors.affiliation: Department of Occupational and Environmental Medicine, Cheongju Medical Center, 48 Heungdeok-ro, Seowon-gu, Cheongju city, Chungbuk, South Korea. ottogee@hanmail.net.
authors.forename: Keun-Hoe
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Occupational and Environmental Medicine, Hallym University Sacred Heart Hospital, 22 Gwanpyeong-ro 170 beon-gil, Dongan-gu, Anyang, Kyeonggi, South Korea. zorro@hallym.ac.kr.
authors.forename: Young-Su
authors.initials: YS
authors.lastname: Ju
authors.affiliation: Department of Occupational and Environmental Health, Graduate School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, South Korea. paekdm@snu.ac.kr.
authors.forename: Domyung
authors.initials: D
authors.lastname: Paek
authors.affiliation: Department of Preventive Medicine, School of Medicine, Eulji University, 143-5, Yongdu-dong, Jung-gu, Daejeon, South Korea. lwydnjd@gmail.com.
authors.forename: Wonyun
authors.initials: W
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D004651:Employment / Q000523:psychology* / Q000706:statistics & numerical data; D005260:Female; D006304:Health Status; D006801:Humans; D007588:Job Satisfaction; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009790:Occupations / Q000145:classification; D012649:Self Concept; D012959:Socioeconomic Factors; D014940:Work Schedule Tolerance; D016526:Workload / Q000523:psychology* / Q000706:statistics & numerical data; D017132:Workplace / Q000523:psychology* / Q000706:statistics & numerical data