Rapid decline in FEV1 and the development of bronchitic symptoms among new Chinese coal miners.
Wang-ML; Petsonk-EL; Wu-Z; Du-Q; Peng-K; Li-Y; Li-S; Han-G; Attfield-MD
Proceedings of the 10th International Conference on Occupational Respiratory Diseases, April 19-22, 2005, Beijing, China. Geneva: International Labour Office, 2005 Apr; :587-592
Newly hired Chinese underground coal miners enrolled in a three-year prospective cohort study were previously shown to experience a nonlinear pattern of FEV1 change (slope) over time. Study miners (n=317) experienced a rapid FEV1 decline during the first year of employment, a plateau during the second year, and partial recovery during the third year of dust exposure. We here report the relationship between the FEV1 changes observed in this cohort and development of bronchitic symptoms (persistent cough and/or phlegm) during the study, using a mixed effect model. Bronchitic symptoms were significantly increased at the 11-month survey and stayed elevated thereafter, with an average incidence of 8.2%. Miners were categorized into four groups by combinations of symptom development (Br+ and Br-) and current smoking (Sm+ and Sm-). At 24 months follow-up, miners who both developed bronchitic symptoms and smoked (Br+ Sm+ group) shwoed the sharpest drop in FEV1, losing 234 ml, after controlling for other co-variables, followed by the Br+Sm- group (-194 ml), Br- Sm+ group (-186 ml), and the Br- Sm- group (-98 ml). Among new coal miners, the development of bronchitic symptoms contributes to a sharp early decline in lung function, as does tobacco smoking.
Coal-workers; Coal-mining; Coal-miners; Underground-mining; Underground-miners; Occupational-exposure; Dusts; Dust-exposure; Dust-particles; Bronchial-asthma; Models; Smoking; Lung-function; Tobacco-smoke; Pulmonary-system-disorders; Respiratory-system-disorders; Surveillance
Proceedings of the 10th International Conference on Occupational Respiratory Diseases, April 19-22, 2005, Beijing, China