The prevalences and levels of occupational exposure to dusts and/or fibres (silica, asbestos and coal): A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.

BACKGROUND: The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large number of individual experts. Evidence from human, animal and mechanistic data suggests that occupational exposure to dusts and/or fibres (silica, asbestos and coal dust) causes pneumoconiosis. In this paper, we present a systematic review and meta-analysis of the prevalences and levels of occupational exposure to silica, asbestos and coal dust. These estimates of prevalences and levels will serve as input data for estimating (if feasible) the number of deaths and disability-adjusted life years that are attributable to occupational exposure to silica, asbestos and coal dust, for the development of the WHO/ILO Joint Estimates. OBJECTIVES: We aimed to systematically review and meta-analyse estimates of the prevalences and levels of occupational exposure to silica, asbestos and coal dust among working-age (≥ 15 years) workers. DATA SOURCES: We searched electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and CISDOC. We also searched electronic grey literature databases, Internet search engines and organizational websites; hand-searched reference lists of previous systematic reviews and included study records; and consulted additional experts. STUDY ELIGIBILITY AND CRITERIA: We included working-age (≥ 15 years) workers in the formal and informal economy in any WHO and/or ILO Member State but excluded children (< 15 years) and unpaid domestic workers. We included all study types with objective dust or fibre measurements, published between 1960 and 2018, that directly or indirectly reported an estimate of the prevalence and/or level of occupational exposure to silica, asbestos and/or coal dust. STUDY APPRAISAL AND SYNTHESIS METHODS: At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, then data were extracted from qualifying studies. We combined prevalence estimates by industrial sector (ISIC-4 2-digit level with additional merging within Mining, Manufacturing and Construction) using random-effects meta-analysis. Two or more review authors assessed the risk of bias and all available authors assessed the quality of evidence, using the ROB-SPEO tool and QoE-SPEO approach developed specifically for the WHO/ILO Joint Estimates. RESULTS: Eighty-eight studies (82 cross-sectional studies and 6 longitudinal studies) met the inclusion criteria, comprising > 2.4 million measurements covering 23 countries from all WHO regions (Africa, Americas, Eastern Mediterranean, South-East Asia, Europe, and Western Pacific). The target population in all 88 included studies was from major ISCO groups 3 (Technicians and Associate Professionals), 6 (Skilled Agricultural, Forestry and Fishery Workers), 7 (Craft and Related Trades Workers), 8 (Plant and Machine Operators and Assemblers), and 9 (Elementary Occupations), hereafter called manual workers. Most studies were performed in Construction, Manufacturing and Mining. For occupational exposure to silica, 65 studies (61 cross-sectional studies and 4 longitudinal studies) were included with > 2.3 million measurements collected in 22 countries in all six WHO regions. For occupational exposure to asbestos, 18 studies (17 cross-sectional studies and 1 longitudinal) were included with > 20,000 measurements collected in eight countries in five WHO regions (no data for Africa). For occupational exposure to coal dust, eight studies (all cross-sectional) were included comprising > 100,000 samples in six countries in five WHO regions (no data for Eastern Mediterranean). Occupational exposure to silica, asbestos and coal dust was assessed with personal or stationary active filter sampling; for silica and asbestos, gravimetric assessment was followed by technical analysis. Risk of bias profiles varied between the bodies of evidence looking at asbestos, silica and coal dust, as well as between industrial sectors. However, risk of bias was generally highest for the domain of selection of participants into the studies. The largest bodies of evidence for silica related to the industrial sectors of Construction (ISIC 41-43), Manufacturing (ISIC 20, 23-25, 27, 31-32) and Mining (ISIC 05, 07, 08). For Construction, the pooled prevalence estimate was 0.89 (95% CI 0.84 to 0.93, 17 studies, I2 91%, moderate quality of evidence) and the level estimate was rated as of very low quality of evidence. For Manufacturing, the pooled prevalence estimate was 0.85 (95% CI 0.78 to 0.91, 24 studies, I2 100%, moderate quality of evidence) and the pooled level estimate was rated as of very low quality of evidence. The pooled prevalence estimate for Mining was 0.75 (95% CI 0.68 to 0.82, 20 studies, I2 100%, moderate quality of evidence) and the pooled level estimate was 0.04 mg/m3 (95% CI 0.03 to 0.05, 17 studies, I2 100%, low quality of evidence). Smaller bodies of evidence were identified for Crop and animal production (ISIC 01; very low quality of evidence for both prevalence and level); Professional, scientific and technical activities (ISIC 71, 74; very low quality of evidence for both prevalence and level); and Electricity, gas, steam and air conditioning supply (ISIC 35; very low quality of evidence for both prevalence and level). For asbestos, the pooled prevalence estimate for Construction (ISIC 41, 43, 45,) was 0.77 (95% CI 0.65 to 0.87, six studies, I2 99%, low quality of evidence) and the level estimate was rated as of very low quality of evidence. For Manufacturing (ISIC 13, 23-24, 29-30), the pooled prevalence and level estimates were rated as being of very low quality of evidence. Smaller bodies of evidence were identified for Other mining and quarrying (ISIC 08; very low quality of evidence for both prevalence and level); Electricity, gas, steam and air conditioning supply (ISIC 35; very low quality of evidence for both prevalence and level); and Water supply, sewerage, waste management and remediation (ISIC 37; very low quality of evidence for levels). For coal dust, the pooled prevalence estimate for Mining of coal and lignite (ISIC 05), was 1.00 (95% CI 1.00 to 1.00, six studies, I2 16%, moderate quality of evidence) and the pooled level estimate was 0.77 mg/m3 (95% CI 0.68 to 0.86, three studies, I2 100%, low quality of evidence). A small body of evidence was identified for Electricity, gas, steam and air conditioning supply (ISIC 35); with very low quality of evidence for prevalence, and the pooled level estimate being 0.60 mg/m3 (95% CI -6.95 to 8.14, one study, low quality of evidence). CONCLUSIONS: Overall, we judged the bodies of evidence for occupational exposure to silica to vary by industrial sector between very low and moderate quality of evidence for prevalence, and very low and low for level. For occupational exposure to asbestos, the bodies of evidence varied by industrial sector between very low and low quality of evidence for prevalence and were of very low quality of evidence for level. For occupational exposure to coal dust, the bodies of evidence were of very low or moderate quality of evidence for prevalence, and low for level. None of the included studies were population-based studies (i.e., covered the entire workers' population in the industrial sector), which we judged to present serious concern for indirectness, except for occupational exposure to coal dust within the industrial sector of mining of coal and lignite. Selected estimates of the prevalences and levels of occupational exposure to silica by industrial sector are considered suitable as input data for the WHO/ILO Joint Estimates, and selected estimates of the prevalences and levels of occupational exposure to asbestos and coal dust may perhaps also be suitable for estimation purposes. Protocol identifier: https://doi.org/10.1016/j.envint.2018.06.005. PROSPERO registration number: CRD42018084131.

Estimating of the costs of nonfatal occupational injuries and illnesses in agricultural works in Thailand.

Thailand lacks occupational injury and illness (OII) surveillance for its agricultural sector, a sector that comprises 34% of the total Thai workforce but is not covered by the workers compensation system. This study used data from Thailand's Universal Health Care System to estimate the medical costs of OIIs from agricultural work in Thailand. In 2017, OII medical costs totaled $47 million (USD), about ~ 0.2% of the gross domestic product produced by the Thai agricultural sector. We recommend that some of the national funds currently used for medical treatment of OIIs be used instead to develop and implement prevention programs in agriculture. This would improve not only worker health and safety, but also productivity. Availability of data on working conditions, injuries and illnesses, and especially lost time, lost income and productivity, and OII-related costs for the workers and their dependents might enable better public health policy formulation.

Assessment of physicians' proficiency in reading chest radiographs for pneumoconiosis, based on a 60-film examination set with two factors constituting eight indices.

Two hundred and thirty-three individuals read chest x-ray images (CXR) in the Asian Intensive Reader of Pneumoconiosis (AIR Pneumo) workshop. Their proficiency in reading CXR for pneumoconiosis was calculated using eight indices (X1-X8), as follows: sensitivity (X1) and specificity (X2) for pneumoconiosis; sensitivity (X3) and specificity (X4) for large opacities; sensitivity (X5) and specificity (X6) for pleural plaques; profusion increment consistency (X7); and consistency for shape differentiation (X8). For these eight indices, one-way analysis of variance (ANOVA) and Scheffe's multiple comparison were conducted on six groups, based on the participants' specialty: radiology, respiratory medicine, industrial medicine, public health, general internal medicine, and miscellaneous physicians. Our analysis revealed that radiologists had a significant difference in the mean scores of X3, X5, and X8, compared with those of all groups, excluding radiologists. In the factor analysis, X1, X3, X5, X7, and X8 constituted Factor 1, and X2, X4, and X6 constituted Factor 2. With regard to the factor scores of the six participant groups, the mean scores of Factor 1 of the radiologists were significantly higher than those of all groups, excluding radiologists. The two factors and the eight indices may be used to appropriately assess specialists' proficiency in reading CXR.

Asbestos-related diseases in Thailand and review literature.

Asbestos is a harmful substance that can cause both malignancy and non-malignancy in humans. Although it has been used in Thailand for several years, few cases of asbestos-related diseases were reported. Concerning about high consumption and long exposure of asbestos in the country, the incurable but preventable diseases caused by asbestos will be the health problem in the near future. The authors presented 2 cases with asbestos-related diseases, one diagnosed as malignant mesothelioma and the other as asbestosis.