Tendency of cumulative incidence of coal workers' pneumoconiosis in a coal mine in Huaibei City / 中国职业医学

ABSTRACT

OBJECTIVE: To analyze the tendency of incidence in coal workers' pneumoconiosis( CWP) in different time of dust exposure and different types of work in a mining enterprise in Huaibei City. METHODS: A total of 12 152 dust exposed workers who worked from 1970 to 2014 in a mining enterprise in Huaibei City were chosen as study subjects by judgment sampling method. They were divided into 2 cohorts were formed according to initial year of dust exposure( 1970-,1980-),and 4 group according to the type of work( tunneling,mining,combining and helping). Life table method was adopted to calculate cumulative life-incidence of CWP in each cohort. RESULTS: Among 12 152 workers,there were 594 of them diagnosed as CWP patients with a 4. 89% of incidence. During the same 34-year-observation period,the cumulative CWP incidence of 1970-cohort was higher than that of the 1980 s( 8. 03% vs 5. 45%,P < 0. 01). The cumulative CWP incidence of tunneling,mining,combining and helping workers were 69. 33%,40. 53%,36. 66% and 19. 70% by 2014,respectively. The cumulative incidence of CWP in tunneling group started to rise from the 14-year-observation window,mining's from 16-year-observation window,combining and helping workers from 18-year-observation window. Among the workers in 1970-cohort at the 34-year-observation window,the CWP cumulative incidence in mining group was the highest( 33. 83%,P < 0. 004),and combining's was the lowest( 2. 28%,P < 0. 004). Among the workers in 1970-cohort at the 44-year-observation window,the CWP cumulative incidence in tunneling group was the highest( 66. 66%,P < 0. 004),and helping's was the lowest( 27. 24%,P < 0. 004). Among the workers in 1980-cohort at the 34-year-observation window,the CWP cumulative incidence in tunneling group was the highest( 29. 87%,P < 0. 004). CONCLUSION: The cumulative incidence of CWP patients was slowed down with prolonged dust exposure starting time. There were differences among different types of workers with different starting time of dust exposure.