Abstract: Respiratory Symptoms and Patterns of Pulmonary Dysfunction among Roofing Fiber Cement Workers in the South of Thailand: Phayong

impairments and respiratory symptoms have been mostly reported in epidemiological studies. The causal associations between cement dust exposure and pulmonary diseases have been studied by epidemiologic and animal studies. The influenced mechanisms of dust deposition are impaction, sedimentation, and diffusion through the respiratory system. Dust greater than 10 μm in aerodynamic diameter are generally captured in the upper respiratory tract, nose and upper airway, whereas smaller particles can penetrate more deeply, reaching the airways and alveoli regions. Particles smaller than 2.5 μm have a greater likelihood of reaching alveoli areas. Fell et al. (2010) observed a significantly higher percentage of neutrophils among exposed workers compared with non-exposed workers. There have been a number of studies on effects of cement dust exposure on respiratory symptoms and illnesses. In a 4-year prospective cohort study in European countries, Nordby et al. (2011) showed elevated relative risks of respiratory symptoms and airflow obstruction (OR=1.2−2.6). In a follow up study of Zeleke et al. (2011) forced expiratory volume in one second (FEV1) and FEV1 per forced vital capacity (FEV1/FVC) were significantly reduced in exposed workers compared with the controls. Neghab and Choobineh (2007) revealed a significant association of respiratory symptoms among exposed cement workers. Similarity, chest radiographs of exposed workers showed various degrees of abnormality. In a cross-sectional study, Mwaiselage et al. (2005) observed an annual decline in FEV1 and FVC for cement dustexposed workers compared to control workers. In addition, cement dust exposed workers were at high risk of developing chronic obstructive pulmonary diseases (COPD) . Noor et al. (2000) and Yang et al. (1996) showed chronic exposure to cement dust resulted in a greater prevalence of chronic respiratory symptoms and a reduction in ventilatory Abstract: Respiratory Symptoms and Patterns of Pulmonary Dysfunction among Roofing Fiber Cement Workers in the South of Thailand: Phayong THEPAKSORN, et al. College of Public Health Sciences, Chulalongkorn University, Thailand—Objective: This study examined the associations between respiratory symptoms and patterns of pulmonary dysfunction of 115 male roofing cement workers compared with 134 unexposed subjects. Methods: A cross-sectional study was conducted. Environmental samplings and spirometry measurements were also collected. Results: The exposed workers had higher respiratory dust exposure levels (0.65 mg/m3) compared with the unexposed groups (0.32 mg/m3). The exposed group had significantly higher prevalence than the unexposed group for shortness of breath (OR=2.19). The exposed group also had higher but insignificant prevalence of chronic cough (OR=1.34), chest tightness (OR=1.64), and wheezing (OR=1.89). The ventilatory respiratory function values (FEV1 and FVC) were slightly lower for the exposed group. Conclusion: An association between higher cement dust levels and a decline in ventilatory function among roofing fiber cement workers suggests that the respiratory health of roofing cement workers should be protected through policies or work standards. (J Occup Health 2013; 55: 21–28)