Objective  To analyze the characteristics of pneumoconiosis in Heze City, and to observe the relationship between dust exposure time and occurrence of pneumoconiosis, the death trend of pneumoconiosis patients and the factors affecting their survival time.

  Methods  A total of 608 patients with pneumoconiosis diagnosed in Heze City from 1971 to 2019 were investigated, pneumoconiosis mortality and expected life span were analyzed by life table method, and the survival was analyzed by Cox case risk regression model.

  Results  Among the 608 patients, 575 cases were diagnosed as pneumoconiosis with stage I, 24 cases with stage Ⅱ and 9 cases with stage Ⅲ. The age was mainly distributed between 50-70 years old and the dust exposure time was mainly less than 10 years. The major jobs were mainly pure tunneling workers, rock diggers and main tunneling workers. The dust exposure time of these pneumoconiosis patients varied from 1 to 34 years. The linear regression equation of follow-up time(x) and cumulative survival probability(ŷ)was: ŷ = 1.070 7 - 0.037 6 x (r = - 0.937 1, P < 0.001), the estimated cumulative survival rate of pneumoconiosis after 20 years of initial diagnosis was 31.87%;the theoretically expected life span of patients with all-cause pneumoconiosis was 11.37 years during follow-up time of 0-1 year. Cox regression analysis results showed that the risk of death of patients with phase Ⅲ was 8.590 times higher than that of patients with phase I, and the rock diggers and main tunneling workers was 3.150 times than pure tunneling workers (P < 0.05). Compared with the cases diagnosed in the previous year, the risk of death of patients diagnosed in this year decreased to 0.970 times(P < 0.05).

  Conclusions  The improvement of living standards and the implementation of various guarantees can prolong the life of pneumoconiosis patients. More attention should be paid to the medical follow-up of previous dust-exposed workers while strengthening the regulation of key industries, key posts and populations.