Objectives To study welding fume particles in relation to cardiovascular diseases.

Methods In 1986, 10 059 male metal workers in 75 welding companies were sent a questionnaire about their welding experience and lifestyle (83.3% response rate). Of these, 5866 were available for analysis and had ever welded at baseline. Information on exposure to welding fumes after 1986 was obtained by individual linkage to the National Pension Fund. Lifelong exposure to welding fume particles was estimated from a job–exposure matrix based on more than 1000 welding-specific measures of fume particles. Hospital contacts for cardiovascular disease were obtained from the Danish National Patient Registry by individual linkage. The nine disease outcomes considered were acute myocardial infarct (AMI), angina pectoris, other acute ischaemic heart diseases, chronic ischaemic heart disease (CHD), cardiac arrythmias, cardiac arrest, heart failure, cerebral infarct, arterial embolism and thrombosis. The cohort was followed up from baseline until the end of 2006.

Results When the incidence of each of the nine cardiovascular outcomes among welders was compared with 5-year age- and calendar year-specific male national rates, the number of observed cases significantly exceeded that expected for AMI (standardised incidence ratio, 95% CI) (1.12, 1.01 to 1.24), angina pectoris (1.11, 1.01 to 1.22), CHD (1.17, 1.05 to 1.31) and cerebral infarct (1.24, 1.06 to 1.44). Internal comparisons of the cohort with adjustment for tobacco smoking, alcohol and hypertension medicines showed a significantly increasing hazard rate ratio for CHD and non-significant increases for AMI, angina pectoris and cerebral infarct with increasing exposure to particles.

Conclusions This study supports the hypothesis that exposure to welding processed particles increases the risk for cardiovascular disease.