Rapid Decline in Forced Expiratory Volume in 1 Second (FEV₁) and the Development of Bronchitic Symptoms Among New Chinese Coal Miners

Objective: To investigate the relationship between the development of bronchitic symptoms and the early rapid decline of forced expiratory volume in 1 second (FEV₁). Methods: A two-stage and a mixed model approach were used to analyze data from 260 newly hired Chinese coal miners who completed approximately 5 to 16 health surveys dunng 3 years. Results: The proportion of miners with onset of bronchitic symptoms was significantly elevated after 11 months of underground mining. Miners with incident symptoms had greater declines in FEV₁ compared with those who did not (— 65 vs —23 mL/yr, P < 0.05). At 24 months follow-up, FEV₁ had declined an average 235 mL among the 26 miners who developed bronchitic symptoms and smoked, compared with a decline of 96 mL among the 132 nonsmoking miners without symptoms. Conclusions: Among new coal miners, a sharp early decline in FEV₁ is associated with the development of bronchitic symptoms.