Does occupational exposure to brown coal dust cause a decline in lung function?

Area of Science:

• Occupational Health
• Environmental Medicine
• Pulmonary Medicine

Background:

• Latrobe Valley brown coal dust exposure is a concern for respiratory health.
• Previous studies have investigated the link between coal dust and lung function decline.
• Understanding the impact of coal dust exposure is crucial for setting workplace safety standards.

Purpose of the Study:

• To investigate the association between high exposure to Latrobe Valley brown coal dust and the rate of decline in forced expiratory volume in one second (FEV1).
• To compare lung function changes in subjects with high coal dust exposure versus those with low exposure.
• To evaluate if current exposure standards for brown coal dust are sufficient to prevent respiratory disease.

Main Methods:

• Retrospective dynamic cohort study over 14 years (1980-1994).
• Utilized data from the State Electricity Commission (SEC) Lung Function Unit.
• Employed spirometry to assess lung function and a general linear model (GLM) to analyze FEV1 changes, adjusting for age, height, and smoking.

Main Results:

• The average rate of FEV1 decline was 40 ml/year.
• Both smoking and coal dust exposure were significant predictors of FEV1 change (P=0.02 and P=0.008, respectively).
• A significant difference in FEV1 decline was observed only between high and mixed exposure categories, not between high and low.

Conclusions:

• No convincing evidence indicates excessive FEV1 decline with coal dust exposure exceeding 0.75 mg/m3.
• The lack of a dose-response relationship suggests against a causal link between coal dust exposure and significant FEV1 decline.
• Current exposure standards for brown coal dust in Victoria's electricity industry do not require reduction to prevent respiratory disease.