Longitudinal limits of normal decline in lung function in an individual

Area of Science:

• Occupational Medicine
• Pulmonology
• Biostatistics

Background:

• Workplace spirometry is crucial for monitoring lung function.
• Identifying excessive decline in forced expiratory volume in 1 second (FEV1) is vital for early intervention.
• Existing methods for calculating limits of normal decline (LND) may lack optimal sensitivity.

Purpose of the Study:

• To propose and evaluate a novel method for calculating LND in FEV1.
• To assess the effectiveness of the proposed LND method in identifying workers with excessive lung function decline.
• To compare the proposed LND method against existing published LND methods.

Main Methods:

• Utilized longitudinal spirometric data from 12,729 workers across 11 workplace programs (1987-2001).
• Defined excessive FEV1 decline using criteria of slope >60 mL/year or >90 mL/year over 5+ years.
• Evaluated LND method effectiveness based on sensitivity in identifying true excessive decline.

Main Results:

• The proposed LND method demonstrated significantly higher sensitivity compared to the American College of Occupational and Environmental Medicine LND method.
• Sensitivity improvements ranged from 2.7 to 5.0 times higher over the first 5 years for the >60 mL/yr criterion.
• The proposed method proved more adept at detecting excessive lung function decline.

Conclusions:

• The newly proposed LND method is more effective for identifying excessive declines in lung function.
• This method offers improved sensitivity for detecting abnormal FEV1 decline in occupational settings.
• The findings support the adoption of this enhanced LND method for worker lung health surveillance.