Proportionate mortality study of unionized maintenance of way railroad workers

Railroad maintenance of way (MOW) workers are exposed to many workplace hazards, including diesel fuel and exhaust, ballast (silica) dust, asbestos, solvents, herbicides, welding fumes, heavy rolling equipment, vibration and extreme weather.

Due to the number of excess deaths we found in a companion standardized mortality ratio (SMR) study for union members <65 years, we hypothesized that these workers may have elevated mortality risks among all ages for many chronic conditions.

Proportionate mortality ratios (PMRs) were calculated for 37 661 male MOW workers ages 20 and older who were members of the Brotherhood of Maintenance of Way Employes Division (BMWED). A data set was submitted to the National Death Index (NDI) to identify decedents and to determine cause of death for workers who died between 1979 and 2014. The CDC WONDER database was used to determine expected mortality for US males.

For certain diseases and cancers the SMR and PMR findings have parallel mortality excesses. Examples include septicaemia and anaemia; diabetes; chronic obstructive pulmonary disease (COPD); nephritis; and transportation accidents. Among cancers, we found excess oesophageal, stomach, colorectal, lung, prostate, kidney and in situ cancers. Two excess SMR findings were not replicated in the PMR assessment-Alzheimer's and Parkinson's disease.

The PMR findings suggest that some of the mortality excesses from the SMR study are elevated, which adds support to their being consistently raised among BMWED members. The shared excess causes of death in the PMR and SMR studies should be focused on for future prevention and surveillance activities.