«Ukrainian scientific-research Institute of industrial Мedicine», Krivoy Rog, Ukraine

SUMMARY. Relevance. Morbidity with temporary disability is an important criterion for assessing the impact of working conditions on the workers ' health. The identification of causal relationships of diseases with working conditions of employees gives the possibility to develop preventive measures to prevent disease and improve the health of employees.

Aim. To assess the level and structure of morbidity with temporary disability of workers engaged in the mining of iron ore by open way in the modern mining industry.

Materials and Methods. To assess the incidence of workers were analyzed sick leave, reports on the causes of temporary disability. For processing the results of the study used mathematical-statistical methods.

The Results of the Study and their Discussion. Level STP is 146,90±7.27 cases (p<0,05), 1617,07±66,61 disability days (p<0,05), the average duration of one case constituted of 11,01±0,34, 1,42 times higher than cases and 1,58 times higher for the disability days than workers in the control group Structure STP: first place is occupied by diseases of the respiratory system (58,54 %) of 69,44±1,21 cases (p<0,05), in second place are illnesses of the musculoskeletal system and connective tissue (13,04 %) of 15,51±0.86 cases (p<0,05), in third place injury, poisoning and certain other consequences of external factors (7,92 %) of 9,42±0,13 cases (p<0,05), the fourth place is occupied by diseases of the digestive system (4,56 %) of 5,43±0,19 cases (p<0,05), the fifth place is occupied by diseases of the circulatory system (4,17 %) of 4,96±0,21 cases (p<0,05).

Conclusions. The results that can be obtained of the analysis of morbidity with temporary disability of workers of these professions can be regarded as source data and open up prospects for further study of the risks of as the common professional diseases and development of complex of preventive measures aimed at reducing not only diseases with temporary disability, and a pair of professional and occupational pathology.

Key Words: open pit mining of iron ore, morbidity with temporary disability.

Rationale. One of the main directions of the social welfare policy of the State is to uphold safe working conditions and healthy households to ensure the health of the working population [2, 9, 10].

Ore mining and smelting is an important line of business and industry of Ukraine; at the same time, it is one of the main contributors to occupational disease. In Ukraine, iron ore mines are core constituents of regional economies and a foundational element of the national economy, which support the essential well-being of population living in these areas. There are five major iron ore enterprises in Ukraine. All of them are concentrated in the Kryvyi Rih Iron Ore Basin [6].

At the same time, the working conditions in this industry (dust, heavy manual labour, significant psychological and emotional stress, adverse microclimate, vibration and noise) remain potential health hazards for workers, not only causing occupational disease but also increasing overall morbidity [1, 7, 11].

Long-term exposures to adverse occupational factors alter the incidences and the structure of individual nosological forms of disease among the workers, including complications of the general somatic disease.

With increasing levels of occupational and general physical illness, major businesses in the industry experience financial losses through downtime, sick leaves and incapacitation payments [9].

Morbidity with temporary incapacitation is an important criterion to assess how workplace conditions influence the health of workers. Identification of respective causative relationships helps to develop prophylactic interventions to prevent disease and to improve workers’ health.

Objective of the study. To evaluate the levels and the patterns of morbidity with temporary incapacitation (MTIC) in workers of the modern mining industry engaged in open mining of iron ore.

Materials and methods. The author has studied morbidity with temporary incapacitation (MTIC) in workers of leading occupations in modern mining industry and in control subjects, who labour continuously (yearlong) under their respective occupation-specific workplace conditions. When the author assessed this problem, the attention was focused on individual occupations, where workers laboured under their respective occupational conditions for not less than 3 years. The study covered 6 years (2011–2016). The main workplace specialities of the workers employed in the transportation of raw mining material in open mining of iron ore included excavator operator and assistant excavator operator, electric locomotive driver and assistant electric locomotive driver and haul truck driver.

The control group included conventional truck drivers of the industrial truck fleet, whose work was to transport cargo and materials within the premises of mining processing plant and in whom occupational hazard levels are within threshold limit values (TLV) and maximum permissible limits (MPL), which corresponds to Class 2 of the hygienic classification (permissible).

The number of workers in the main group was 4,754 persons; the control group included 982 persons.  The study groups were homogeneous in terms of age and working experience of the participants; therefore, the results may be viewed as robust. Morbidity with temporary incapacitation was reviewed in terms of all principal nosologies.

In order to assess morbidity, the author has reviewed medical certificates for sick leave and medical reports on causes of temporary incapacitation. Methods of mathematical statistics have been used to process the results of the study.

Results and discussion: the majority of workers in either the main group or in the control group had over 15 years of experience in their respective specialities. Among the workers of the principal occupations engaged in the transportation of raw mining material, there were no workers younger than 21 years of age. Therefore, this age group was not respectively taken into account in the control group.

During analysis of MTIC in workers engaged in transportation of iron ore, MTIC level was 146.90 ± 7.27 cases (р < 0.05) (from 158.46 ± 7.44 in excavator operators to 132.57 ± 6.65 in assistant excavator operators) with 1,617.07 ± 66.61 days of incapacitation (р < 0.05) (from 1,687.04 ± 80.16 days in excavator operators to 1,457.98 ± 54.25 days in assistant excavator operators), mean duration of one case was 11.01 ± 0.34 days (from 11.16 ± 0.31 days in electric locomotive drivers to 10.73 ± 0.08 days in excavator operators), which was 1.42 times higher case-wise and 1.58 times higher in terms of days of incapacitation compared to the workers in the control group; according to L. E. Notkin scale, these results can be interpreted as “very high” in terms of days and “high” in terms of number of cases.

In the control group, the number of MTIC-associated days of incapacitation was 102.91 ± 4.84, which is significantly less than in the main group (р < 0.05). The total number of days of incapacitation was 1,023.31 ± 72.24, which also was significantly less than in the main group (р < 0.05); according to L. E. Notkin scale, this is assessed as “above average” (both case-wise and in terms of days of incapacitation). The mean duration of one case in workers of the main group was 11.01 ± 0.34 days compared to 9.94 ± 0.62 days in the control group, which suggests a more severe and protracted course of disease in workers of the main group.

Table 1

Assessment of MTIC levels at principal workplaces and in the control group between 2012 and 2017 (per 100 employees) (p < 0.05)

Note* = the difference from the control group is significant (р < 0.05).

During analysis of MTIC structure in workers engaged in open mining of iron ore, morbidity with temporary incapacitation has the following pattern: the first place belonged to respiratory disorders (58.54 %) with 69.44 ± 1.21 cases (р < 0.05), the second place belonged to musculoskeletal and connective tissue disorders (13.04 %) 15.51 ± 0.86 cases (р < 0.05), the third place belonged to injuries, poisonings and other consequences of external factors (7.92 %) 9.42 ± 0.13 cases (р < 0.05), the fourth place belonged to digestive tract disorders (4.56 %) 5.43 ± 0.19 cases (р < 0.05) and the fifth place was occupied by circulatory disorders (4.17 %) 4.96 ± 0.21 cases (р < 0.05).

In the control group, MTIC cases had the following pattern: the first place belonged to respiratory disorders with 54.68 ± 1.07 cases (58.4 %), the second belonged to injuries and poisonings 7.81 ± 0.78 cases (8.3 %; р < 0.05), the third belonged to musculoskeletal and connective tissue disorders with 6.86 ± 0.13 cases (7.3 %; р < 0.05), the fourth belonged to circulatory disorders with 4.89 ± 0.16 cases (5.2 %; р < 0.05) and the fifth place belonged to digestive tract disorders with 4.56 ± 0.11 cases (4.86 %; р < 0.05).

Such parameter as days of incapacitation characterizes labour losses of the staff due to health reasons and corporate profit losses due to incapacitation through morbidity and injuries, as well as irreversible health problems in workers of the industry.

The incidence of temporary incapacitation due to disease is of primary importance since any changes in the incidence suggests the impact of working conditions on workers’ health.

Conclusions

1. During review of MTIC findings, it was found that the workers engaged in transportation of iron ore have MTIC level at 146.90 ± 7.27 cases (р < 0.05) with 1,617.07 ± 66.61 days of incapacitation (р < 0.05); mean duration of one case was 11.01 ± 0.34, which was a 1.42-fold difference case-wise and a 1.58-fold difference in terms of days of incapacitation from the workers of the control group; according to L. E. Notkin scale, these figures are “very high” in terms of days and “high” in terms of cases.
2. The distribution of MTIC in workers engaged in open mining of iron ore had the following pattern: the first place belonged to respiratory disorders with 69.44 ± 1.21 cases (58.54 %; р < 0.05), the second belonged to musculoskeletal and connective tissue disorders with 15.51 ± 0.86 cases (13.04 %; р < 0.05), the third belonged to injuries, poisonings and other consequences of external factors with 9.42 ± 0.13 cases (7.92 %; р < 0.05), the fourth belonged to digestive tract disorders with 5.43 ± 0.19 cases (4.56 %; р < 0.05) and the fifth place belonged to circulatory disorders with 4.96 ± 0.21 cases (4.17 %; р < 0.05).
3. Therefore, the findings of morbidity with temporary incapacitation in workers of the mining industry can be viewed as background data that call for further investigation into the risk factors of both overall and occupational morbidity and to develop a program of prophylactic interventions aimed at reducing not only temporary incapacitating disease but also occupational and occupation-related disease.

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Надійшла до редакції 11.06.2018 р.