Aim of the study. To examine differences in lung function between petroleum refinery workers and office workers and to evaluate working in petroleum refinery as a predictor of the values of lung function parameters.
Methods. We performed a cross-sectional study including 90 male petroleum refinery workers, aged 32-60 years. In addition, 40 male office workers, aged 47-59 years were examined as a control. Evaluation of examined subjects included completion of a questionnaire on general and respiratory symptoms in the last 12 months and lung function testing (all parameters expressed in %predicted). Several multiple regression models were tested to examine the associations of working in a petroleum refinery to lung function parameters controlling for age, duration of employment, exposure duration, daily smoking, life-time smoking, and number of cigarettes per day.
Results. Mean values of lung function parameters (FVC, FEV1, MEF75, MEF50 and MEF25) were similar in both groups. Mean FEV1/FVC value was significantly lower in petroleum refinery workers (83.13 ± 7.16) than in controls (87.1 ± 7.44) (t=-2.88; p=0,005). Multiple regression analysis showed that daily smoking (β = -.803) and cigarettes/day (β = -.507) were significant predictors of lower FEV1 (R2 = .09, ΔR2 = .08, ΔF=1.97, p=0.015). Working in a petroleum refinery (β = -.228) negatively predicted FEV1/FVC (R2 = .097, ΔR2 = .047, ΔF=6.36, p=0.013).
Conclusion. Our data suggest important role of specific occupational exposure, daily smoking, and number of cigarettes per day in the development of reduced lung function.