Abstract

The incidence of myocardial infarction and the return to work for survivors were studied among the employees of an English car assembly plant by analysing 12 811 medical records of persons employed during the seven years between January 1966 and December 1972. The standardized morbidity ratio of myocardial infarction found in this study calculated on the basis of incidence rates reported by Kinlen )1973) for the Oxford community in which the factory was situated was 90. The standardized morbidity ratio from production line workers only was 66 and that for the monthly paid staff 272. Of the production line workers who survived the attack 22 (90%) returned to their previous jobs without undue difficulty and with two exceptions within four months of the onset of their illness; there was no relation between length of absence and age at the time of attack. These findings suggest that workers in mass production jobs such as car assembly are not special risk from myocardial infarction, and most of those who survive a heart attack are able to return to their former work. Taken with Kinlen's (1973) study and that of Armstrong et al. (1972) in Edinburgh, they also bear out mortality data by indicating that in Oxfordshire the incidence of coronary heart disease is lower than the British average.