Occupational exposures and pancreatic cancer: a meta-analysis

Objectives-Consolidation of epidemiological data on pancreatic cancer and w orksite exposures. Methods-Publications during 1969-98 were surveyed. Studies without verified exposures were excluded. Meta-analyses were conducted on data fi om 92 stu dies covering 161 populations, with results for 23 agents or groups of agen ts. With a standard format, five epidemiologists extracted risk estimates a nd variables of the structure and quality of each study. The extracted data were centrally checked. Random meta-models were applied. Results-Based on 20 populations, exposure to chlorinated hydrocarbon (CHC) solvents and related compounds was associated with a meta-risk ratio (MRR) of 1.4 (95% confidence interval (95% CI) 1.0 to 1.8). Nickel and nickel com pounds were considered in four populations (1.9; 1.2 to 3.2). Excesses were found also for chromium and chromium compounds (1.4; 0.9 to 2.3), polycycl ic aromatic hydrocarbons (PAHs) (1.5; 0.9 to 2.5), organochlorine insectici des (1.5; 0.6 to 3.7), silica dust (1.4; 0.9 to 2.0), and aliphatic and ali cyclic hydrocarbon solvents (1.3; 0.8 to 2.8). Evidence on pancreatic carci nogenicity was weak or non-positive for the following agents: acrylonitrile (1.1; 0.0 to 6.2); arsenic (1.0; 0.6 to 1.5); asbestos (1.1; 0.9 to 1.5); diesel engine exhaust (1.0; 0.9 to 1.3); electromagnetic fields (1.1; 0.8 t o 1.4); formaldehyde (0.8; 0.5 to 1.0); flour dust (1.1; 0.3 to 3.2); cadmi um and cadmium compounds (0.7; 0.4 to 1.4); gasoline (1.0; 0.8 to 1.2); her bicides (1.0; 0.8 to 1.3); iron and iron compounds (1.3; 0.7 to 2.5); lead and lead compounds (1.1; 0.8 to 1.5); man-made vitreous fibres (1.0; 0.6 to 1.6); oil mist (0.9; 0.8 to 1.0); and wood dust (1.1; 0.9 to 2.5). The occ upational aetiological fraction of pancreatic cancer was estimated at 12%. in a subpopulation exposed to CHC solvents and related compounds, it was 29 %; to chromium and chromium compounds, 23%; to nickel and nickel compounds, 47%; to insecticides, 33%; and to PAHs, 33%. Conclusion-Occupational exposures may increase risk of pancreatic cancer. H igh quality studies are called for on interactions between occupational, en vironmental, and lifestyle factors as well as interactions between genes an d the environment.