Respiratory mucus transportability is impaired in foundry workers: a longitudinal study

Area of Science:

• Occupational Health
• Respiratory Physiology
• Environmental Medicine

Background:

• Impaired mucus transportability can lead to prolonged retention of inhaled occupational toxins in airways.
• The Normalized Frog Palate Transport Rate (NFPTR) is a validated, non-invasive marker for assessing mucus transportability.

Purpose of the Study:

• To compare NFPTR in foundry workers (E) versus power plant workers (NE) over three years.
• To investigate the association between NFPTR, occupational exposure, and respiratory function.

Main Methods:

• Prospective study involving 166 foundry workers and 133 power plant workers.
• Annual assessments included clinical examination, spirometry, NFPTR measurements, and chest radiography.
• Environmental monitoring confirmed low irritant concentrations below established limits.

Main Results:

• Foundry workers (E) exhibited significantly lower mean NFPTR compared to power plant workers (NE) in both the first and third years.
• Lower NFPTR was observed in smokers versus non-smokers at follow-up.
• NFPTR impairment was significantly linked to occupational exposure and, by year three, also to smoking, FVC, and FEV1/FVC.
• Foundry workers showed significantly lower FVC, FEV1, and PEF by study's end; no pneumoconiosis was detected.

Conclusions:

• Low-dose respiratory irritants in foundries are associated with impaired mucus transportability.
• Reduced mucociliary clearance due to NFPTR impairment increases internal exposure to airborne toxins.
• Findings highlight the risk of impaired airway clearance even at low occupational irritant levels.