Estimation of ventilatory capacity in subjects with unacceptable lung function tests.

Area of Science:

• Occupational Health
• Pulmonary Medicine
• Epidemiology

Background:

• Pulmonary function tests (PFTs) are crucial for assessing respiratory health in occupational settings.
• Current epidemiological standards recommend excluding PFTs with non-reproducible results.
• The impact of excluding non-reproducible PFTs on study outcomes is not fully understood.

Purpose of the Study:

• To investigate the association between non-reproducible pulmonary function tests (PFTs) and lung function in granite workers.
• To evaluate the potential selection bias introduced by excluding workers with initial PFT failures.

Main Methods:

• Longitudinal study of 540 Vermont granite workers over six years.
• Extrapolation of initial FEV1 (Forced Expiratory Volume in 1 second) from subsequent measurements.
• Comparison of extrapolated FEV1 between workers with and without initial PFT failures, adjusting for confounders.

Main Results:

• The extrapolation method accurately predicted initial FEV1 (R2 = 0.87).
• Workers with initial PFT failures showed a trend towards lower extrapolated FEV1 (p = 0.07).
• Increasing PFT failures correlated with a significant decrease in percent predicted FEV1 (p = 0.0004).

Conclusions:

• Excluding workers with non-reproducible PFTs may lead to underestimation of respiratory impairment.
• Findings suggest the need for alternative strategies to analyze non-reproducible lung function data.
• Revising current exclusion criteria could improve the accuracy of epidemiological studies on occupational lung diseases.