Factors predictive of ischemic heart disease mortality in foundry workers exposed to carbon monoxide

The potential predictors of ischemic heart disease mortality were studied f or 931 male foundry workers in Finland who participated in a health examina tion in 1973. These workers were followed up to 1993 through registers and by using a questionnaire. In 1973, the systolic and diastolic blood pressur es of workers exposed to carbon monoxide (CO) were slightly higher than tho se of unexposed workers. The prevalence of angina pectoris showed a clear d ose-response relation to CO exposure. Electrocardiogram (ECG) findings indi cating past myocardial infarction or suggesting coronary artery disease as a function of smoking and/or CO exposure were not evident. In the 1987 foll ow-up, the rate ratio for ischemic heart disease mortality was estimated as 4.4 for CO-exposed smokers compared with unexposed nonsmokers. Ischemic he art disease mortality in 1973-1993 was analyzed by using the Cox proportion al hazards model. The statistically significant predictors were age, pathol ogic ECG findings in 1973, regular CO exposure, and abundant alcohol drinki ng. Of the ECG findings, changes in Q or QS and ST-J or ST waves and in ven tricular extrasystoles were statistically significant, The risk of mortalit y from ischemic heart disease was increased by working in iron foundries, b y hypertension, and by smoking.