Occupational Pneumoconiosis and Disease Latency

Occupational Lung Diseases (OLDs)

• OLDs are caused or aggravated by exposures at the workplace, substantially contributing to the burden of chronic respiratory diseases.
• OLD is not a single diagnosis, but rather encompasses a range of pulmonary diseases, including:
• Idiopathic pulmonary fibrosis (PAF, 26%)
• Occupational asthma (most commonly diagnosed OLD)
• Asthma (PAF, 16%)
• Chronic bronchitis (PAF, 13%)
• Other OLDs, such as acute and chronic conditions, ranging from hypersensitivity pneumonitis to chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis.

Burden of OLDs

• The attributable fraction found in an exposed group:
• Idiopathic pulmonary fibrosis (PAF, 26%)
• Asthma (PAF, 16%)
• Chronic bronchitis (PAF, 13%)
• Other granulomatous diseases, such as sarcoidosis (occupational burden, 30%)
• Hypersensitivity pneumonitis (occupational burden, 19%)
• Tuberculosis (occupational burden, 2.3% and 1% in silica-exposed workers and healthcare workers)
• Community-acquired pneumonia in working-age adults (PAF, 10%)

Characteristics of OLDs

• Disease latency period: disease typically appears after at least 20 or more years from the first exposure to the recognition of clinical symptoms.
• Some diseases may first appear and even progress many years from the end of exposure.

Pulmonary Alveolar Proteinosis

• Second-highest occupational burden (29%)
• Associated with a broad range of exposures, including:
• Vapors or gases, such as cleaning fluids and hair spray
• Inorganic dust, such as silica (PAF for silica, 5%)
• Organic dust, such as wood and metal dusts or fumes, including aluminum

Healthcare Workers (HCWs) and Infectious Respiratory Diseases

• HCWs are at increased risk for contracting many infectious respiratory diseases, including:
• Latent tuberculosis infection (LTBI) and active TB disease
• Screening programs are in place to catch disease early, including yearly CT lung scans for:
• Asymptomatic adults aged 55-80 years who have a 30 pack-year smoking history
• High-risk workers may be similarly screened

Occupational Exposures and Lung Diseases

• Between 1990-2015, there were increases in average occupational exposure to:
• Diesel exhaust (72.1% men; 129.8% women)
• Silica (72.6% men; 44.9% women)
• Benzene (48.5% men; 97.5% women)
• Launderers, dry cleaners, and pressers were found to have the greatest risk of lung diseases resulting from occupational exposures to cleaning products.

Coal Workers' Pneumoconiosis (CWP) / Black Lung Disease

• Seen a recent resurgence in prevalence and severity
• Caused by respirable fine crystalline silica, silicates, and metal content of coal mine dust
• Risk factors for development of COPD in miners depend on:
• Duration and extent of dust exposure
• Prior dust exposure, and the presence of other risk factors, especially cigarette smoking and silica (surface mining)

Prevention and Control of OLDs

• The only way is to avoid work and work sites where exposure to certain levels of agents occur
• Facility managers have to know what agents in their plant have been associated with asthma and inform workers to maintain exposure below known sensitizing levels
• Material safety sheets should include information on components that may cause or exacerbate asthma