|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1999 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1998 : ¥2,400,000 (Direct Cost : ¥2,400,000)
Since a topic on the "sudden death" was limelighted in Japanese workers, more than ten years have passed. Although myocardial infarction due to overwork has been suggested to be a main causal disease of sudden death, the causation between them remains unclear. At least, periodic health examination, carried out in the workplace every year, seems to have little value for the prediction of such a death/disease. For this reason, the significance of ten items of the periodic health examination stipulated in the Industrial Safety and Health Act (44 sections), I.e., blood pressure, urinalysis, anemia, liver function, lipid, electrocardiogram (ECG), etc., is impeached.
The main results of this research are as follows: (1) The ECG data were compared between workers who died suddenly and healthy workers, but no significant difference in the abnormal waveforms was found between them. The ECG data obtained at the time of the periodic health examination did not appear to be effective for the predict
ion of sudden death. (2) What was the most effective for the prediction of sudden death was viewed by using the past references. Some papers have reported that the heart-rate corrected QT interval (QTc) of ECG and heart rate variability are very useful for the prognosis of patients with myocardial infarction and diabetes mellitus. (3) The most reasonable estimate of the relative risk for cardiovascular diseases induced by shift work has been suggested to be around 1.4. To determine whether shift work affects the QTc and blood pressure of workers without overt cardiovascular dysfunction, shift workers and day workers who underwent an ECG examination and blood pressure measurements in 1986 were followed for 10 years. The shift workers had a significantly longer QTc than the day workers, and the adjusted odds ratio of shift work to the prolonged QTc (440 msecィイD11/2ィエD1) was 8.15 (90% confidence interval, 1.31-50.5). These findings suggest that the increased risk for cardiovascular mortality in shift workers may be attributable to prolongation of the QTc.