RESUMEN
Background: Different kinds of smoking tobacco may affect pulmonary function and reduce some spirometric parameters. This study aimed to assess the relationship between smoking cigarettes and waterpipe and spirometric parameters. Methods: This was a cross-sectional study on 1543 middle-aged individuals, as a sub-study of the Shahedieh cohort study in Yazd. The participants were randomly selected from the Shahedieh cohort population and were divided into 6 groups according to their smoking habits: non-smokers (n=455), cigarette smokers (n=139), waterpipe smokers (n=287), ex-cigarette smokers (n=131), concurrent waterpipe and cigarette smokers (n=121), and cigarette or waterpipe passive smokers (n=410). Spirometry was performed on all participants and spirometric parameters were compared between different groups. The data were analyzed by SPSS (version 20) using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Findings: FEV1 %, FEV1/FVC, and PEF25-75% were significantly lower in cigarette smokers, compared to waterpipe smokers and non-smokers. The measures were not significantly lower in waterpipe smokers in comparison to non-smokers. The frequency of obstructive pattern and small airway diseases was significantly higher in cigarette smokers compared to waterpipe smokers and non-smokers. Conclusion: The results of this study showed that in the middle-aged population, spirometric parameters related to airway obstruction (FEV1, FEV1/FVC, and FEF25-75%) were significantly lower in cigarette smokers than in non-smokers and waterpipe smokers, but these parameters were not significantly different between waterpipe smokers and non-smokers.
RESUMEN
Background: The adverse health effects of silica are still a major concern in some industries. The purpose of this study was to evaluate pulmonary function in a group of sub-radiological silicotic workers after 11 years of silica dust exposure. Methods: The study sample consisted of 381 exposed and 254 non-exposed workers. The history of pulmonary function parameters was obtained from workers' medical records. The data were collected through interviews with employees and completing questionnaires on demographic variables, detailed occupational and medical history, and respiratory symptoms. Workers' exposure to silica dust was also determined. Results: The mean frequency of workers' exposure to silica dust was 6.3 times greater than its exposure limit. All pulmonary function parameters were significantly lower in the silica-exposed workers, and the difference between the two groups was still statistically significant after adjusting the potential confounding variables. FEV1 showed the greatest reduction, and FVC and FEV1 showed a significant decreasing trend. Also the prevalence of respiratory symptoms was significantly higher in smokers than in nonsmokers among silica-exposed workers. Conclusions: Even in the absence of radiographic evidence of silicosis, exposure to high levels of silica dust is associated with reductions in pulmonary function. In the absence of radiological evidence of silicosis, progressive deterioration of FEV1 over time most likely indicates sub-radiological silicosis. The effects were associated with the severity and duration of exposure. Exposure to sub-TLV levels of silica dust may not affect pulmonary function. Smoking appears to have a synergistic effect in relatively high silica exposures.
