Iranian Journal of

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Background & Objectives: The main purpose of this study was to assess the pulmonary reactions associated with occupational inhalation exposure to raw materials used in ceramic production (RMCP).
Methods: Thirty three male workers with current exposure to RMCP and 20 healthy male unexposed employees, ,with almost identical demographic and socioeconomic status were interviewed and respiratory symptom questionnaires were administered to them. Furthermore, they underwent chest X-ray and lung function tests. Additionally, personal dust monitoring was carried out at dusty work sites. To determine the chemical composition, possible silica phases and SiO2 contents of dust samples, they were analyzed by X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques.
Results: Atmospheric concentrations of dust, that contained 69% SiO2­, exceeded current permissible levels. Additionally, exposed workers had higher prevalence rates of regular cough, wheezing, phlegm and shortness of breath. Likewise, their chest radiographs showed some degrees of abnormalities. Furthermore, significant reductions in some parameters of pulmonary functions of exposed workers were noted.
Conclusions: The findings of this study indicate that a strong association exists between exposure to RMCP, prevalence of respiratory symptoms, abnormal changes in chest radiographs and functional impairments of the lungs.

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Recently, capture-recapture studies have been used and researchers tend to use these studies in the health field. Therefore, we discussed the basic concepts of these studies. First, we described capture-recapture studies. Then, the important assumptions and calculations were presented according to the close population assumption. Statistical formulas were presented for two-capture methods and dependency between the two lists was discussed. Then, we addressed more than two capture methods.