ABSTRACT
OBJECTIVES: 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.
Subject(s)
Cardiovascular Diseases/etiology , Personnel Staffing and Scheduling/statistics & numerical data , Work Schedule Tolerance/physiology , Cardiovascular Diseases/epidemiology , Case-Control Studies , Female , Humans , Incidence , Logistic Models , Male , Middle Aged , Occupational Diseases/epidemiology , Occupational Diseases/etiology , Population Surveillance/methods , Prospective Studies , Republic of Korea/epidemiology , Risk Factors , Time Factors , Work Schedule Tolerance/psychologyABSTRACT
BACKGROUND: Iron and steel foundry workers are exposed to various toxic and carcinogenic substances including crystalline silica, polycyclic aromatic hydrocarbons, and arsenic. Studies have been conducted on lung cancer in iron and steel founding workers and the concentration of crystalline silica in foundries; however, the concentration of crystalline silica and cases of lung cancer in a single foundry has never been reported in Korea. Therefore, the authors report two cases of lung cancer and concentration of crystalline silica by the X-ray diffraction method. CASE PRESENTATION: A 55-year-old blasting and grinding worker who worked in a foundry for 33 years was diagnosed with lung cancer. Another 64-year-old forklift driver who worked in foundries for 39 years was also diagnosed with lung cancer. Shot blast operatives were exposed to the highest level of respirable quartz (0.412 mg/m3), and a forklift driver was exposed to 0.223 mg/m3. CONCLUSIONS: The lung cancer of the two workers is very likely due to occupationally related exposure given their occupational history, the level of exposure to crystalline silica, and epidemiologic evidence. Further studies on the concentration of crystalline silica in foundries and techniques to reduce the crystalline silica concentration are required.