Early respiratory effects of long-term cement dust exposure: association with exercise capacity in asymptomatic workers.

PURPOSE: Long-term occupational exposure to cement dust is associated with respiratory disease, yet early subclinical impairment may not be detected using conventional spirometry. This study aimed to investigate small airway dysfunction (SAD) as an early marker of respiratory effects and its association with exercise capacity in asymptomatic cement workers.

METHODS

We studied 500 non-smoking, non-asthmatic, non-atopic cement industry workers aged 35 years or older, with at least 10 years of occupational exposure to cement dust. Participants underwent spirometry, static lung volume measurements, impulse oscillometry (IOS) and cardiopulmonary exercise testing (CPET). Workers with evidence of SAD were compared to those with normal small airway function.

RESULTS

Small airway dysfunction was identified in a subset of workers despite preserved spirometry. The SAD group exhibited a 19.4% reduction in VO2 peak compared to the non-SAD group (29 ± 2.3 vs. 36 ± 2.0 ml/kg/min, p < 0.05). This functional limitation was further characterised by a significantly lower breathing reserve (34% vs. 43%, p < 0.05) and increased ventilatory requirements during exercise.

CONCLUSIONS

Subclinical respiratory impairment may occur in a significant proportion of asymptomatic workers with long-term exposure to cement dust. SAD may serve as an early functional marker of occupational lung disease. Conventional spirometry underestimates the functional impact of exposure; therefore, sensitive techniques should be integrated into occupational surveillance for early detection and support preventive workplace strategies.