Reliability of a questionnaire assessing occupational exposure to diesel exhaust and health effects

Abstract

Diesel exhaust is an important airborne contaminant in workplaces where diesel-powered equipment or vehicles are used. Currently the exposure assessment to diesel exhaust and related health effects in Australian working populations remains relatively under studied. This study aimed to assess the reliability of a questionnaire that was used to assess workplace diesel exhaust exposure and basic information regarding the health status of workers exposed to diesel exhaust. The questionnaire was developed based on a validated questionnaire from the American Thoracic Society Questionnaire, 'OcclDEAS', a web-based application tool to assess hazards related to occupational exposure and the 'Health Assessment Form' created by the Western Australian Department of Mines and Petroleum. The questionnaire included questions on occupational and non occupational hazards exposure histories, current exposure conditions, medical history, respiratory symptoms and possible confounders. There were 29 main questions, a further 94 components, and a total 123 parts. It was administered on two occasions (eight months apart) to workers of a local logistics company.The response rate was 84%. Reliability was assessed by using paired sampled t-tests and correlations; agreement between retest variables was further assessed using kappa. The questions assessed demonstrated good reliability. On average 26.1% had a chronic respiratory condition, 23.9% had hay fever and 13% had a chronic cardiovascular condition. Chronic respiratory conditions were more common in workers exposure to diesel exhaust (P=0.016). In summary a reliable questionnaire has been developed in this pilot study. This questionnaire can be utilized for further larger studies to examine this important population health problem.