Effects of occupational exposures on respiratory health in steel factory workers.

Background: The steel factory work environment contains various chemical exposures that can affect indoor air quality and have impact on respiratory health of the workers. Aims: The objective of this study was to assess potential effects of occupational exposures in steel factory workers in Iran on the respiratory symptoms, occurrence and the lung function levels. Method: This was a cross-sectional study of 133 men working in a steel factory forming the exposed group and 133 male office workers forming the reference group from a steel company in Iran. The participants filled in a questionnaire and underwent spirometry. Work history was used both as dichotomous (exposed/reference) and a quantitative measure of exposure, the latter measured as duration of exposure in the specified work (in years) for the exposed group and zero for the reference group. Results: Multiple linear regression and Poisson regression were used to adjust for confounding. In Poisson regression analyses, an increased prevalence ratio (PR) of all respiratory symptoms was observed in the exposed group. Lung function parameters were significantly reduced in the exposed group (p < 0.001). There was a dose-response relation between duration of occupational exposures and reduction in the predicted value of FEV1/FVC level (0.177, 95% CI -0.198 to -0.156) in all models. Conclusion: The results of these analyses showed that occupational exposures in steel factory work increase the prevalence of respiratory symptoms and reduce lung function. Safety training and workplace conditions were found to need improvement. In addition, use of proper personal protective equipment is recommended.

Mycobacterium Avium Complex (MAC) Lung Disease in Two Inner City Community Hospitals: Recognition, Prevalence, Co-Infection with Mycobacterium Tuberculosis (MTB) and Pulmonary Function (PF) Improvements After Treatment.

INTRODUCTION: The purpose of this study was to separate MAC lung disease from colonization and to define indications for treatment. MATERIALS AND METHODOLOGY: Over 4 years, we evaluated patients who had positive MAC cultures, MAC infection and coinfection with MTB. In the first study, 42 immunocompetent patients with sputum or BAL culture positive only for MAC during a single year (2004) were reviewed. On clinical and radiographic review, they were classified as disease related to MAC, likely related to MAC or unrelated to MAC. In the second study, we reviewed all immunocompetent patients, during two years (2004-2005), whose respiratory secretions cultured both MTB and nontuberculous mycobacteria (NTM). In the last study, we evaluated pulmonary function (PF) in patients with MAC infection before and after therapy (2006- 2007). PF was evaluated in patients following ATS guidelines. RESULTS: Lung disease was related/likely related to MAC in 21 patients (50%) and not related in 21 (50%). In patients with MAC-related lung disease, the primary physician did not consider the diagnosis except when that physician was a pulmonologist. Half of those with MAC-related lung disease were smokers, white and US-born. There were 12 immunocompetent patients with MTB and NTM cultures. Eleven were non-white and all were foreign-born. Presentation and clinical course were consistent with MTB. All 8 patients with abnormal PF improved. CONCLUSIONS: The prevalence of MAC lung infection in two inner city hospitals was four times higher than that of TB. The indication for treatment of MAC infection should also rely heavily on clinical and radiological evidence when there is only one positive sputum culture. The diagnosis was considered only when the admitting physician was a pulmonologist. Most patients with combined infection were clinically consistent with MTB and responded to anti MTB treatment alone. Treatment with anti-MAC therapy improved PF in those patients whose PF was abnormal to begin with.