The world is experiencing a burgeoning epidemic of diabetes associated with increased rates of overweight and obesity.1 Evidence has accumulated that obesity is associated with a state of chronic low-grade inflammation and that intracellular signalling pathways activated by inflammatory responses are associated with insulin resistance.2 3 Diesel exhaust particulate (DEP) has been shown to increase markers of systemic and pulmonary inflammatory response in volunteers4 and studies of human bronchial epithelial cells in vitro have suggested that DEP induces proinflammatory substances by activating their transcription.5

Heavy equipment operators (HEOs) are occupationally exposed to DEP. Should these exposures augment a state of chronic low-grade systemic inflammation, then these workers might be at increased risk of diabetes. In …