Lung-function reference values from Victorian power-industry workmen

Work-related symptoms and dose-response relationships for personal exposures and pulmonary function among woodworkers

BACKGROUND

Four sawmills, a wood chipping mill, and five joineries in New South Wales, Australia, were studied for the effects of personal exposure to wood dust, endotoxins. (1-->3)-beta-D-glucans, Gram-negative bacteria, and fungi on lung function among woodworkers.

METHODS

Personal inhalable and respirable dust sampling was carried out. The lung function tests of workers were conducted before and after a workshift.

RESULTS

The mean percentage cross-shift decrease in lung function was markedly high for woodworkers compared with the controls. Dose-response relationships among personal exposures and percentage cross-shift decrease in lung function and percentage predicted lung function were more pronounced among joinery workers compared with sawmill and chip mill workers. Woodworkers had markedly high prevalence of regular cough, phlegm, and chronic bronchitis compared with controls. Significant associations were found between percentage cross-shift decrease in FVC and regular phlegm and blocked nose among sawmill and chip mill workers. Both joinery workers and sawmill and chip mill workers showed significant relationships between percentage predicted lung function (FVC, FEV1, FEV1/FVC, FEF25-75%) and respiratory symptoms.

CONCLUSIONS

Wood dust and biohazards associated with wood dust are potential health hazards and should be controlled.

Quantitative relation between emphysema and lung mineral content in coalworkers

The relation between quantified emphysema and measured lung content of coal and silica was investigated in the lungs of 264 deceased underground coalworkers who had been exposed to mixed coal and silica dust. Lung specimens obtained at postmortem and inflated and fixed under standard conditions were used to quantify the extent of emphysema and then to measure the amount of coal and silica present in the lungs at the time of death. These data were combined with clinical and other pathological information from the subjects. Multiple regression analysis showed that the extent of emphysema (E score) had a strong positive quantitative relation with coal content of the lungs (p < 0.0003), age (p < 0.0001), and smoking (p < 0.0001). There was a significant negative interaction of uncertain biological importance between coal content of the lungs and smoking (p < 0.004; E score = -1.79 + 0.62 coal + 0.06 age + 0.21 smoking -0.17 coal x smoking; adjusted R2 = 0.25). In lifelong non-smokers emphysema was particularly strongly related to coal content and age (coal: p < 0.001; age: p < 0.002; E score = -1.56 + 0.78 coal + 0.06 age; adjusted R2 = 0.66). The relation was basically unchanged by adding a lung silica content term. Emphysema score was highly negatively correlated with forced expiratory volume in one second (FEV1; % predicted, obtained within five years of death) (r = -0.44, p < 0.0001). Degree of lung fibrosis was highly positively associated with lung silica content (chi 2(1) = 12.9, p < 0.0003). These results provide strong evidence that emphysema in coalworkers is actually related to lung coal content. The role silica in development of emphysema, however remains unclear.