Penpatra Sripaiboonkij

Respiratory and skin effects of exposure to wood dust from the rubber tree Hevea brasiliensis

Objectives: Potential health effects related to wood dust from the rubber tree, which produces natural rubber latex, have not been previously investigated. The main aim of this study was to investigate the relations of rubber tree dust exposure to respiratory and skin symptoms, asthma and lung function. Methods: A cross-sectional study was conducted among 103 workers (response rate 89%) in a rubber tree furniture factory and 76 office workers (73%) in four factories in Thailand. All participants answered a questionnaire and performed spirometry. Inhalable dust levels were measured in different work areas. Results: Factory workers showed increased risk of wheezing, nasal symptoms and asthma compared to office workers. There was a dose-dependent increase in wheeze and skin symptoms in relation to dust level. Significantly increased risks of nasal symptoms (adj OR 3.67, 95% CI 1.45 to 9.28) and asthma (8.41, 1.06 to 66.60) were detected in the low exposure category. Workers exposed to ethyl cyanoacrylate glue had significantly increased risk of cough, breathlessness and nasal symptoms. There was dose-dependent reduction in spirometric lung function with wood dust level. Conclusions: This study provides new evidence that workers exposed to wood dust from the rubber tree experience increased risk of nasal symptoms, wheeze, asthma and skin symptoms and have reduced spirometric lung function. Exposure to cyanoacrylate is related to significantly increased respiratory symptoms. Results suggest that the furniture industry using rubber tree wood should implement appropriate exposure control measures to reduce wood dust exposure and cyanoacrylate glue exposure to protect their employees.

Asbestos Exposure among Mitering Workers

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

Respiratory and skin health among glass microfiber production workers: a cross-sectional study

Objectives A few studies have investigated non-malignant respiratory effects of glass microfibers and these have provided inconsistent results. Our objective was to assess the effects of exposure to glass microfibers on respiratory and skin symptoms, asthma and lung function. Methods A cross-sectional study of 102 workers from a microfiber factory (response rate 100%) and 76 office workers (73%) from four factories in Thailand was conducted. They answered a questionnaire on respiratory health, occupational exposures, and lifestyle factors, and performed spirometry. Measurements of respirable dust were available from 2004 and 2005. Results Workers exposed to glass microfibers experienced increased risk of cough (adjusted OR 2.04), wheezing (adjOR 2.20), breathlessness (adjOR 4.46), nasal (adjOR 2.13) and skin symptoms (adjOR 3.89) and ever asthma (adjOR 3.51), the risks of breathlessness (95% CI 1.68 to 11.86) and skin symptoms (1.70 to –8.90) remaining statistically significant after adjustment for confounders. There was an exposure-response relation between the risk of breathlessness and skin symptoms and increasing level of microfiber exposure. Workers exposed to sensitising chemicals, including phenol-formaldehyde resin, experienced increased risk of cough (3.43, 1.20 to 9.87) and nasal symptoms (3.07, 1.05 to 9.00). Conclusions This study provides evidence that exposure to glass microfibers increases the risk of respiratory and skin symptoms, and has an exposure-response relation with breathlessness and skin symptoms. Exposure to sensitising chemicals increased the risk of cough and nasal symptoms. The results suggest that occupational exposure to glass microfibers is related to non-malignant adverse health effects, and that implementing exposure control measures in these industries could protect the health of employees.

Vitamins as asthmagens in the workplace - Reply

Significant differences in asthmagenicity are not observed between the provitamin, the naturally occurring vitamin or its synthetic derivative used in industry. The positive predictive value of the QSAR for the identification of suspect chemical asthmagens is .50%. Even in the context of testing random chemicals for asthmagens, the QSAR has a negative predictive value of 100%; thus vitamins B6, C and K are certainly nonasthmagens. The property of water or fat solubility, which forms the basis of the traditional classification of vitamins, does not seem to be a determinant of a vitamin’s asthma hazard index. Skin sensitisers are typically more hydrophobic than respiratory sensitisers. Both water-soluble and fat-soluble vitamins are used as additives in the food industry. Exposure at work to both of the above classes of vitamin compounds may occur, resulting in respiratory and skin sensitisation of workers during the manufacturing process.We recently reported results of a cross-sectional study of 167 milk powder factory workers and 76 office workers from Thailand showing that production and packing workers exposed to relatively low concentrations of milk powder experienced significantly increased risk of nasal symptoms and breathlessness, had clearly increased risk of wheezing and asthma, and had reduced spirometry 1. Workers who added a vitamin mixture to milk had significantly increased risk of skin symptoms, in addition to having increased risk of nasal symptoms and reduced lung function. A.D. Vellore and colleagues address the respiratory sensitisation potential of vitamins by applying a quantitative structure-activity relationship model developed by Jarvis et al. 2 for low molecular weight agents. Based on an asthma hazard index calculated by the model, they conclude that vitamins, apart from vitamins B6, C and K, have high …