Certain U.S. railroad workers have exposures to diesel exhaust, welding fumes, herbicides, ballast (silica) and asbestos dust, creosote, solvents and fuels, heavy equipment vibration, and weather extremes. We hypothesize that these workers are at elevated mortality risk for chronic pulmonary and kidney disease, neurological ailments, as well as cancers of the respiratory and digestive tracts, prostate cancer, and lymphatic cancers.Methods
The names of craft union railroad workers were submitted to the U.S. National Death Index for the years 1979 to 2014. When a match was found for name, gender, social security number, and date of birth, these persons were reported and their underlying cause of death was organized into groups according to their ICD code. Using union membership data from 1996–the midpoint of the follow-up period–we calculated standardized mortality ratios (SMRs) and 95% confidence intervals for 11,190 deceased males, aged 18 to 64.Results
Compared to the U.S. males, these unionized railroad workers have an all cause SMR of 1.63. Parkinson's and Alzheimer's diseases show elevated SMRs of 3.09 and 7.15, respectively; hypertensive and atherosclerotic heart disease show elevated SMRs of 2.11; chronic respiratory disease (including COPD) has a SMR of 1.89 (95% CI: 1.66 to 2.13); kidney disease has a SMR of 2.50 (95% CI: 1.99 to 3.01); and transportation accidental deaths have a SMR of 3.27 (95% CI: 3.08 to 3.46). All cancers show a SMR of 1.79. Stomach, bladder, colo-rectal cancers and leukemia have an approximate risk of 2.0; liver cancer has a SMR of 2.36 (95% CI: 1.95 to 2.78); pancreatic cancer produced a SMR of 2.17 (95% CI: 1.84 to 2.50); lung cancer has a SMR of 1.82 (95% CI: 1.71 to 1.94); prostate cancer produced a SMR of 1.93 (95% CI: 1.52 to 2.34); and bladder cancer has a SMR of 1.95 (95% CI: 1.35 to 2.55).Discussion
With an SMR of 3.27, the risk among these unionized rail workers from transportation accidents is consistent with daily work around heavy rolling equipment. Elevated risks for kidney, heart, neurological diseases, and COPD are consistent with dust or hydrocarbon exposures from ballast and other hazardous exposures. Our findings suggest that the increased SMR for all neoplasms is likely based on elevated risks for cancers of the bladder, pancreas, prostate, liver, and lung.