A cohort study of mortality among Ontario pipe trades workers.
OBJECTIVE
To study mortality in a cohort of members of the United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry of the United States and Canada and to compare results with two previous proportional mortality studies.


METHODS
A cohort of 25,285 workers who entered the trade after 1949 was assembled from records of the international head office. Mortality was ascertained by linkage to the Canadian Mortality Registry at Statistics Canada. Standardised mortality ratios were computed using Ontario general population mortality rates as the reference.


RESULTS
There were significant increases in lung cancer mortality rates (SMR 1.27; 95% CI 1.13 to 1.42). Increased lung cancer risk was observed among plumbers, pipefitters, and sprinkler fitters. Increased risk was observed among workers joining the Union as late as the 1970s. A random effects meta-analysis of this study and the two PMR studies found significant increases in oesophageal (RR 1.24; 95% CI 1.00 to 1.53), lung (RR 1.31; 95% CI 1.19 to 1.44), and haematological/lymphatic (RR 1.21; 95% CI 1.08 to 1.35) malignancies.


CONCLUSIONS
The mortality pattern is consistent with the effects of occupational exposure to asbestos. Increased risk due to other respiratory carcinogens such as welding fume cannot be excluded. There are substantial amounts of asbestos in place in industrial and commercial environments. The education and training of workers to protect themselves against inhalation hazards will be necessary well into the future.
Program in Occupational Health and Environmental Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5. murray.finkelstein@utoronto.ca
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Verma
D000368:Aged; D015331:Cohort Studies; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D008175:Lung Neoplasms / Q000401:mortality*; D008669:Metallurgy; D008875:Middle Aged; D009784:Occupational Diseases / Q000401:mortality*; D009864:Ontario / Q000453:epidemiology; D012307:Risk Factors; D015996:Survival Rate