Respiratory symptoms and statistical methods

Abstract

Objectives: To investigate the incidence of respiratory symptoms and changes in pulmonary function in relation to occupational exposures in two aluminium smelters in Victoria, Australia. Methods: The study population consisted of employees who started employment between 1995 and the end of 2003 at two aluminium smelter sites in Victoria, Australia. Participation involved an initial assessment at the start of employment and annual follow-up assessments for the duration of employment at the smelters. These assessments involved an intervieweradministered questionnaire which included questions about cough, shortness of breath, wheeze, chest tightness and rhinitis. In addition lung function was assessed by measuring forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC). Methacholine challenge testing was performed to identify bronchial hyper-responsiveness (BHR). The occupational exposures investigated in this study were fluoride, sulphur dioxide (SO 2 ), inspirable dust, benzene soluble fraction (BSF) and oil mist. The exposure levels to these substances were calculated for each participant in the study using their job history information and routine personal air monitoring data. The random effects model was used to investigate the association between occupational exposures and health outcomes. Results: In total 446 employees participated in the study. Of the five symptoms, only wheeze and chest tightness, the two symptoms most closely related to asthma, showed associations with exposures at the sites. Workers who were exposed to fluoride, inspirable dust, SO 2 and BSF were more likely to report wheeze. Chest tightness was associated with exposure to dust, SO 2 and BSF. Many of the exposures were highly correlated, but it is most likely that fluoride and SO 2 , known respiratory irritants, were responsible for the symptom effects observed. Fluoride, inspirable dust and SO 2 were the most important agents having an effect on lung function. A significant reduction in the FEV 1 /FVC ratio (an indicator of airflow limitation), and declines in both FEV 1 and FVC over time were associated with these exposures. BHR was also related to exposure to fluoride, SO 2 , inspirable dust and BSF. Conclusion: Some occupational exposures in aluminium smelters are associated with increased wheeze and chest tightness and small decrements in lung function and BHR. Key words: aluminium smelter; pulmonary function; respiratory symptoms PREVALENCE OF CHRONIC BRONCHITIS RELATED TO PROFESSIONAL AND ENVIRONMENTAL EXPOSURE TO HYDROCARBONS IN FEMALE WORKERS E. Viragh. Tg-Mures University of Medicine and PharmacyObjectives: This epidemiological field study was conducted to determine the prevalence of chronic bronchitis in female persons exposed to hydrocarbons in the petrochemical industry and the surrounding environment. Methods: Air monitoring in all workplaces and around the factory of aliphatic (AH) and polycyclic aromatic hydrocarbons (PAH) was carried out during a 7-year period. 147 females aged 38.2 (SD 6.1) years and w...

Air pollution exposure and lung function in highly exposed subjects in Beijing, China: a repeated-measure study

“…Our findings are in line with previous studies on the effect of these elements on lung function in occupational settings. The observed association of FEV1 with Al is consistent with previous studies showing an association between lower FEV1 or FVC and exposure to Al in potroom workers [ 13 ], cast-house workers [ 14 ], and smelters [ 15 ], although the Al concentrations in these occupational studies exceeded the concentrations measured in the BTDAS. An experimental study suggested that Al induces oxidative and inflammatory stress, leading to damage of the lung epithelium [ 39 ].…”