What is the guarantee that coal miners are given the most appropriate individual care in relation to their condition hence how competent are health and safety staff?
[1] Bibliographic reference
Scarisbrick, D A & Quinlan, R M 2002, ‘Health Surveillance for Coal Workers’ Pneumoconiosis in the United Kingdom 1998-2000,’ Annals of Occupational Hygiene, vol. 46, no. 1, pp. 254-256.
Major questions posed in the study
1) Which among the causative factors could result in high rates of CWP?
2) How the increase in number of miners and prevalent mining practices could contribute in the increased risk for CWP?
3) How health surveillance could help in reducing rates of CWP?
Method of investigation
Screening procedures are conducted using full-size PA chest x-rays. Simple pneumoconiosis was classified on the basis of categorization – 0, 1, 2 or 3 and extended when necessary. PXR surveys were carried out at 15 collieries for a period of 3 years, inclusive. Written consents of the miners were reported to the Health and Safety Executive (HSE). Prevalence was measured cross-sectional. Results for all exposed personnel were aggregated. Results of PXR in 1998-2000 were compared to data from 1959-1963, 1969-1973, 1978-1981, 1986-1989, 1990-1993 and 1994-1997.
Her Majesty’s Inspectorate of Mines (HMIM) of the HSE also conducted investigations based on the use of respiratory protective equipment (RPE), dust levels, places of work, mining methods and working hours.
Major variables of interest and their operational definitions
a) Prevalence of pneumoconiosis was compared in each of the first, third, fifth, seventh, eight and ninth PXR rounds
b) Incidence is defined as the number of new cases diagnosed at an interval of no more than 4 years
c) Categories 1 and 2+ are the ones compared
d) More substantial tasks are undertaken by contractors
e) Two mines are considered – Collieries A and Collieries B
f) Age was constantly changing considering the length and period of research
g) Prevalence of CWP was 12% in 1959-1963
Study population
Colliery population that includes all men miners and supervisors with exposures to coal dust, underground or on the surface is the target population. Members of colliery management and staff were invited to attend the screening. Because miners works for lengthy periods of time in mines, contractors conducts substantial amount of work in coal mines. In Colliery A, few contractors were involved compared with Colliery B, contractors were extensively involved. Attendance at PXR surveys is voluntary hence the study population is subject to constant change.
The results/findings
The prevalence of all categories of pneumoconiosis at Colliery A was 1.3% and Colliery B at 2.3% while the prevalence of category ≥2 for the two collieries was 0.5 and 12%, respectively. Majority of employees with pneumoconiosis was from Colliery B. The use of RPE was slightly above the national average at the first colliery and significantly below average in the second colliery. Over the 10 year period, dust concentrations in Colliery A were not excessive while Colliery B was considered to be dusty.
Miners who developed pneumoconiosis worked longer than the standard working week. HMIM considered excessive working as the most significant contributor leading to pneumoconiosis at both collieries.
Author’s conclusions and recommendations
The leading cause of the deterioration may be due to the altered age structure of the industry. The most important factor is longer working hours compared to the standard work week by which the statutory dust limits are based. Revision of dust exposure limits would be then necessary.
Evaluation
Commendable is the fact that the research is an original research that considers exploring the reasons of the decline in CWP while also investigating factors that contribute to the prevalence and incidence of CWP.
Another strong point is the analysis of the colliery population and determines which among such population is most affected by categories 1 and 2 of CWP through constant PXR surveys.
The article should be also given merit on the basis of presenting the results of screening from the beginning of 1998 to the end of 2000 and comparing it to data from 1959 to 1997 to provide the bigger picture.
However, the study seems to appear as three different studies. First, the comparison of the data, which should be considered as the background instead as part of the result, from various periods and on the basis of PXR results.
Second, the comparisons of Collieries A and B could be treated as an independent research as it focuses on prevalence of pneumoconiosis with reference to age.
Same with the third that is the comparisons of the two collieries on the basis of HMIM investigations.
Having said these, the research lacks in focus, leading to inadequately discussing the results especially that the research resorted in data fishing wherein among the 15 collieries’ screened only two were chosen, which with apparent differences. Nevertheless, occupational health surveillance refers to the systematic investigation of the occurrence of health outcomes in relation to work conditions (Checkoway, Pierce and Kriebel, 2004). The research, however, fails to elaborate causal associations between workplace exposures and adverse health affects that ultimately may suggest preventive strategies.
The recommendation then is also inadequate because the selection of interventions in worksites needs to provide more complete and detailed information regarding why it should be considered. Stellman (1998) mention that research should provide support for policy development and provide scientific support for setting standards and occupational exposure limits.
It would be better if the author provides in-depth conceptual definition of the role of HSE to provide better understanding of to what extent does health surveillance in collieries is deemed important as taken from the HSE’s perspective. In this way, the researcher could offer how health and safety practitioners’ role affect the health outcomes in worksites (Ashford, 1976).
I therefore conclude that the individual health care should be provided on a needs-basis considering the working conditions and length of working hours of the coal miners. Though they may engage in similar line of work, health outcomes will fundamentally be different because of the fact that there are factors that should be considered such as age, the place of work and various mining practices. Health and safety staff then must understand first the peculiarity of the work and specific activities unique to the coal mining industry.
[2] Bibliographic reference
Mamuya, S H D, Bratveit, M, Mwaiselage, K and Moen, B E 2006, ‘Variability Exposure and Estimation of Cumulative Exposure in a Manually Operated Coal Mine,’ Annals of Occupational Hygiene, vol. 50, no. 7, pp. 737-745.
Major questions posed in the study
1) How exposure-response could positively impact health outcomes of coal miners?
2) How grouping schemes could affect exposures hence limiting attenuation?
3) What do grouping schemes for exposure estimates implicate?
4) How efficient is the grouping approach in the manually operated coal mines?
Method of investigation
Dust sampling strategy was conducted using a total of 110 filter cassettes for respirable dust. Sampling was planned for both surface and underground workers. Workers were randomly selected from the list of workers. Exclusions were made for 220 workers from 556 which were divided into 8 functioning teams. In the first sampling, the researchers had no information on the exposure of coal miners while in the second sampling, reselection was considered. The number of measurements allocated was based on the exposure concentrations obtained from the first period. Personal dust sampling was performed during the day shift for both periods of about 5 to 10 hours. Respirable dust samples were quantified by gravimetric analysis.
Workers were interviewed to determine their occupational history.
Major variables of interest and their operational definitions
a) Distribution of personal exposure to respirable dust is based on a priori job teams
b) Surface workers are regarded as between-workers while underground workers are treated as within-workers
c) A strict definition of uniformly exposed groups is not a prerequisite for identifying a relationship between exposure and health outcome
Study population
Two hundred and ninety-nine (299) men workers were included in the study from surface and underground class which was further identified through teams. These workers comprised of 47 from development, 78 from mine team, 34 from underground maintenance, 30 from underground transport, 23 from washing plant, 17 from boiler and turbine, 21 from ash and cinders and 49 from office. The mean of the numbers of employment is 10.2 years while the mean age is 37.0 years.
The results/findings
Teams with relatively high level of exposure are development team, mine team, transport team and maintenance team compared to surface teams. Surface teams particular those in the office team generally has lower exposure levels to respirable dust. Between-workers’ exposure was low compared to within-workers, varying between 1.0 and 22.5 in the 8 job teams. The development team and the underground maintenance teams have exposure levels that indicate a large day-to-day variation.
Author’s conclusions and recommendations
The variability of the respirable dust exposure was higher among the underground workers than among workers at the surface. Various tasks therefore affect differences in exposure. Time spent on work and the job and the rotation between the tasks could explain the variability levels based on two sampling period. Within-workers variability is considerable in the raw coal and the processed coal areas. Exposure-disease association was highlighted in the study. The overall prevalence of pneumoconiosis was 2-4% and exposure was associated with decline in respiratory function. Occupational history, which may have some recall bias, could also affect the levels of exposure. Authors suggested that the results of the exposure estimates could be used in analyzing the exposure-response relationships for respiratory health affects.
Evaluation
Commendable is the process by which the researchers assess the exposure levels of workers, dividing the group into teams and determine such despite the fact that job rotation is inexistence. Mine management classifications would be important to determine the difference in levels of exposure thus variations in adverse health effects.
Researchers underscored dust sampling strategy as an important indicator of levels of exposure to respirable dust, a practice that is often overlooked in coal industries. Dust sampling strategy is specifically critical in determining respiratory illnesses that may occur in the mines.
The weakest point of the study is its recommendation especially that the researchers point out different confounders in the study such as recall bias, uncertain representativity of the measurements as per worker and risk of misclassifying workers into exposure. Because of this exposure intensity and duration could not be exactly determined, leading to overestimation.
For the recommendation to be accomplished, the confounding variables must first be addressed. Residence is very important in determining exposure levels to warrant an effective recommendation of health programme or intervention for the coal miners. This is explained by French, Reynolds and Swain (2001) by saying that to investigate effectively associations, potential confounders must be addressed and reduced when necessary. Although observed outcomes are exhaustive, the research demonstrates the complexity of measuring associations.
Because the results seemed predictable, the researchers could have examined levels of exposure in between-groups other than between-workers to establish exposure differences especially that the management is embracing job rotation. Job rotation was not clearly explored whether it is job rotation of workers between teams or job rotation within teams. This could have been a better recommendation while also suggesting to conduct further study on health outcomes of surface workers and underground workers.
Regarding the topic, health care provided for the coal miners should be also assessed on the work they are performing and how the characteristics of a working team could likely to influence the health risks of an individual belonging in that team. As such, coal miners depending on their job, age and length of work have varying needs. This aspect would be important in how health and safety staff would commit with their role to intervene by utilizing exposure assessment information.
References
Ashford, N A 1979, Crisis in the Workplace: Occupational Disease and Injury – A Report of the Ford Foundation, MIT Press.
Checkoway, H, Pierce, N and Kriebel, D 2004, Research methods in occupational epidemiology, Oxford University Press.
French, S, Reynolds, F and Swain, J 2001, Practical Research, Elsevier Health Sciences.
Stellman, J M 1998, Encyclopedia of Occupational Health and Safety: The body, health care, management and policy, tools and approaches, International Labor of Organization.
Credit:ivythesis.typepad.com
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