title: Working hours and cardiovascular disease in Korean workers: a case-control study.
abstract: OBJECTIVE
  Long working hours can negatively impact a worker's health. The objective of this study was to examine the association between working hours and cardiovascular diseases (CVDs) and compare the degree of risk based on CVD subtypes in Korean workers.
  
  
  METHODS
  This study was a case-control study of the patients registered in the Occupational Cardiovascular Diseases Surveillance 2010. The cases included 348 patients diagnosed with a CVD (123 cerebral infarction, 69 intracerebral hemorrhage, 57 subarachnoid hemorrhage, 99 acute myocardial infarction). Controls were 769 participants with no history of CVDs matched for gender, age, type of occupation, and region. Participants' working hours in the previous week and the average working hours over the past three months were assessed to examine short-term and long-term effects.
  
  
  RESULTS
  After adjusting for confounding factors, the odds ratios (ORs) for CVDs in the short-term were 2.66 (95% Confidence interval (CI) :1.78-3.99) for working ≤40 hours, 1.85 (95% CI: 1.22-2.81) for working 50.1-60 hours and 4.23 (95% CI: 2.81-6.39) for working >60 hours compared with the 40.1-50-hour working group. The ORs in the long-term were 2.90 (95% CI: 1.86-4.52) for working ≤40 hours, 1.73 (95% CI: 1.03-2.90) for working 48.1-52 hours and 3.46 (95% CI: 2.38-5.03) for working >52 hours compared with the 40.1-48-hour working group.
  
  
  CONCLUSIONS
  Long working hours are related to an increased risk of CVDs, and the degree of risk differs based on CVD subtype. Short working hours are also related to an increased risk for CVDs. More prospective studies targeting specific disease risks are required.
authors.affiliation: Graduate School of Public Health, Yonsei University.
authors.forename: Inchul
authors.initials: I
authors.lastname: Jeong
authors.forename: Jeongbae
authors.initials: J
authors.lastname: Rhie
authors.forename: Inah
authors.initials: I
authors.lastname: Kim
authors.forename: Innshil
authors.initials: I
authors.lastname: Ryu
authors.forename: Pil Kyun
authors.initials: PK
authors.lastname: Jung
authors.forename: Yoo Seok
authors.initials: YS
authors.lastname: Park
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Lim
authors.forename: Hyoung-Ryoul
authors.initials: HR
authors.lastname: Kim
authors.forename: Shin-Goo
authors.initials: SG
authors.lastname: Park
authors.forename: Hyoung-June
authors.initials: HJ
authors.lastname: Im
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Lee
authors.forename: Jong-Uk
authors.initials: JU
authors.lastname: Won
mesh_terms: D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology; D010561:Personnel Staffing and Scheduling / Q000706:statistics & numerical data*; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D013997:Time Factors; D014940:Work Schedule Tolerance / Q000502:physiology* / Q000523:psychology