Article Text
Abstract
Introduction The Rostov region was one of the largest centers of coal mining in Russia during XIX–XX centuries. The long-term effects of work in coal mines were investigated with the use of database of the Rostov regional center of occupational health.
Aim Assessment of mortality risks in different exposure groups of coal miners.
Methods A cohort of 9980 coal miners with established occupational diseases was formed by the Rostov regional center of occupational health. The follow-up period was 26 years (01.01.1990–31.12.2015). By the end of the follow-up period 1898 miners were alive and 8082 died. In result there were 1 38 768 person-years of follow-up. The male population of Rostov region was used as reference group.
Two different exposure groups were created. First one included main professions – clearing face miners and shaft miners (5941 persons, 79 978 person-years). Maximum dust concentrations reached 270–300 mg/m3, vibration levels – 130 dB, noise levels – 130 dBA. The second one included miners of auxiliary professions (shot-firers, wiremen, loco drivers, etc.) – 4039 persons, 58 790 person-years. The maximum exposure levels were lower, 100–130 mg/m3, 110 dB, 105 dBA, respectively.
Results The standardized mortality ratio in the cohort (SMR) was 1.47 (CI 1.42–1.51). In the group with length of service up to 10 years, SMR=1.01 (0.91–1.13), 10–19 years SMR=1.33 (1.27–1.39), 20 years and more SMR=1.91 (1.80–2.02).
In both groups the SMR was higher than in reference population. SMR=1.57 (1.50–1.63) and SMR=1.32 (1.25–1.39) respectively. The difference between subgroups was also statistically significant SMR=1.19 (1.14–1.24)
Conclusion Results of follow up demonstrated elevated risks of mortality for former coal miners. A ‘dose (time) – effect’ relationship for mortality levels were also established.