N. Chaiear^1,, J. Ngoencharee², N. Saejiw³

Objectives: 1) To determine the prevalence of respiratory symptoms and abnormal pulmonary function among workers exposed to different levels of rubber wood dust (RWD) and 2) to determine the factors which may be associated with the respiratory effects. Methods: The study population was 340 workers working in a rubberwood sawmill factory in Nakhon Si Thammarat province, Southern Thailand. Respiratory health questionnaires and spirometric testing according to the ATS 1994 criteria were performed. Workers were classified into three groups by the RWD levels; low RWD (≤ 1.9 mg/m³); moderate RWD (2.0-4.9 mg/m³); and high RWD (≥ 5.0 mg/m³). Results: A total of 279 workers (59 male and 220 female) were participated in the study. Their average age and work duration were 36.7 years (SD=8.5) and 6.2 years (SD=4.1), respectively. The prevalence rate of upper and lower respiratory symptoms were 67.0% and 63.1% respectively. The prevalence of abnormal spirometric testing result was 20.6 % (obstructive type 4.4 %, restrictive type 10.5 %, and small airway disease 5.7 %). These prevalence rates were not significantly different according to the RWD level. However, the factors which were significantly associated with the upper respiratory symptoms were being female [OR 2.03 (95%CI 1.10, 3.78)] and being atopy [OR 3.63 (95%CI 1.88, 7.0)]. The factor which was significantly associated with lower respiratory symptoms was a family of asthma [OR 3.95 (95%CI 1.32, 11.7)]. Conclusion: Exposure to rubber wood dust is associated with a high prevalence of respiratory illnesses and being atopic person takes a high risk of work related respiratory illnesses.

rubber, wood dust, spirometry, asthma, work related asthma