LAUSR

Introduction Overwork-related health disorders including cerebrovascular/cardiovascular diseases (CCVDs) and mental disorders, known as ‘Karoshi’, have been the keen occupational health issue. Main criteria applied for compensation of overwork-related CCVDs in Japan were (1) extraordinary events, (2) excessive working hours in 1 week and (3) long working hours over 100 extra hours in 1 month or over average 80 extra hours in 2–6 months. The present study examined diagnosis of compensated cases as overwork-related CCVDs in Japan. Methods The investigation report for the occupational accident related to CCVDs prepared by 321 labour standards inspection offices all over Japan from January 2010 to March 2015 were collected to JNIOSH-RECORDS. Total 1561 cases which met these criteria were examined from the viewpoint of the diagnosis-related in focusing on sex, age, size of the industry. This study was supported by the research fund of MHLW (No. 150903–01). Results The majority (96%) of all compensated CCVDs cases was male. Fatal cases accounted for 39.2%. A mean age at the onset of CCVDs was 49.3 years old. Intracerebral haemorrhage (ICH) was the highest (28.6%) in the proportion of diagnosis related group, following subarachnoid haemorrhage (SAH, 18.5%), cerebral infarction (CI, 14.6%), hypertensive encephalopathy (HE, 0.3%) in a cerebrovascular disease group. In a cardiovascular disease group, myocardial infarction (MI, 17.1%) was the highest, following cardiac arrest (including sudden cardiac death) (CA, 14.3%), dissecting aortic aneurysm (DAA, 5.2%), angina pectoris (AP, 1.2%). By classifying the industry size, CCVD cases at the workplace hiring less than 50 workers was over half of all cases (52.2%). Discussion Focusing on cerebrovascular diseases accounting for 60% is useful for examining preventive measures. Characteristics of diagnosis contribute to discuss directions for preventing overwork-related CCVDs. It should be paid attention to preventive measures in small sized enterprises that occupational health services are difficult to reach.