Prevalence and predictors of high-frequency hearing loss among mine workers in Gujarat, western India: a cross-sectional study on the need to implement a comprehensive hearing conservation program.

BACKGROUND: High-frequency hearing loss (HFHL) stands as a prevalent occupational morbidity globally, with numerous associated risk factors, some of which are modifiable. In the context of a comprehensive hearing conservation program, the initial steps involve early screening and identification of workers with these modifiable risk factors, aiming to reduce the prevalence of hearing loss. Our objective was to estimate the prevalence of HFHL and determine its predictors among mine workers. METHODS: We conducted a cross-sectional study among 226 mine workers in ten open-cast mines in Gujarat state, the western part of India, in November 2020. We collected data on socio-demography, addiction, occupation history and comorbidities, along with anthropometric, blood pressure, and blood sugar measurements. Audiometric evaluations using a portable diagnostic audiometer were employed to assess HFHL, defined as a hearing threshold exceeding 25 decibels (dB) at high frequencies (3000, 4000, 6000, and 8000 Hz). A generalized linear model (GLM) with a binomial family was performed to determine the predictors significantly predicting HFHL after adjusting for confounding variables. RESULTS: The prevalence of HFHL was 35% (95% CI: 29-42%) in our study setting. Office workers demonstrated a prevalence of 19%, whereas other job categories displayed a higher prevalence of 42%, resulting in a significant prevalence difference of 23% and a prevalence ratio of 2.2. The GLM analysis revealed that variables, such as noise exposure during work [adjusted prevalence ratio (aPR) 2.3 (95% CI: 1.2-4.7, p = 0.018)] and noise exposure duration [aPR 1.1 (95% CI: 1.0-1.1, p = 0.042)], were significant predictors of HFHL. CONCLUSIONS: In our study setting, mine workers exhibited a high prevalence of HFHL, with exposure to workplace noise and duration being modifiable predictors. Because HFHL advances slowly and is generally undetected by the individual, we recommend periodic testing using audiometry to identify it among mine workers and, if possible, shifting them from mining activities to office. Furthermore, we advocate for the implementation of a comprehensive hearing conservation program to the extent possible.

Determinants of discomfort from combined exposure to noise and vibration in dumper operators of mining industry in India.

In the mining industry, dumper operators are exposed to combined noise and vibration, leading to discomfort. Dumpers are heavy earth-moving machines that are used for carrying bulky material in mining industries. Dumper operators are exposed to physical hazards such as vibration, noise, heat, and humidity, throughout their lifetime of work. Fifty-four dumper operators working in mines were selected for this study. Noise was measured as per the guidelines of the Directorate General Mining Safety, India, and whole-body vibration was measured as per the guidelines of ISO 2631-1::1997. Noise Pro DLX, Type 2 noise dosimeters were used for the measurement of personal noise exposure while SV-106 six channels vibration meters were used for whole body vibration (WBV) exposure measurement. Discomfort was calculated using the regression equation developed by Huang and Griffin (2014). The total discomfort level of mine operators was about 192. A predictive equation was derived by using a regression model to determine the contribution of individual variables causing discomfort. It was observed that for every unit increase in noise (LAeq), discomfort increased by 10.20 units, a one-unit increase in vibration (A (8)) led to a 51.7-unit increase in discomfort, while an increase of one unit of exposure time increased the discomfort level by 5.24 units.

Exposure profile of respirable crystalline silica in stone mines in India.

Silicosis is one of the major occupational lung diseases among stone miners; currently, it is a major concern in India given its 12-30% prevalence. The objective of this study was to determine the exposure profile of respirable dust and crystalline silica concentrations from sandstone, masonry stone, and granite stone mines in India. Personal respirable dust samples were collected from each type of mine and analyzed for dust and respirable crystalline silica concentrations. The mean dust concentrations were found to be 0.47 mg/m3, 1.24 mg/m3, and 3.28 mg/m3 for sandstone, masonry stone, and granite stone mines, respectively. The mean respirable crystalline silica concentrations were 0.12 mg/m3 for sandstone mines and 0.17 mg/m3 for masonry stone and granite stone mines. The concentrations in sandstone mines was below the standard stipulated by the Directorate General of Mine Safety in India (0.15 mg/m3), whereas in the granite and masonry mines the concentrations just exceeded the limit. The Indian standard for respirable crystalline silica is three to six times higher than the standard set elsewhere (i.e., by OSHA, ACGIH®, and Egyptian Labor Law standards). Considering the large number of silicosis cases among stone miners in India, the present standard appears inadequate. It is recommended that the standard be lowered to match international standards that minimize the risk of silicosis.

Predictors of pulmonary dysfunction vis-à-vis the hypertension status of mine workers in Gujarat, western India: A cross-sectional study on the need to further investigate the role of anti-hypertensive drugs.

BACKGROUND: Mine workers face various health risks from occupational hazards, notably dust-related pulmonary dysfunction. This dysfunction is also attributed to diverse risk factors and health conditions. Despite the variety of underlying mechanisms, conflicting evidence persists regarding hypertension as a potential risk factor for such dysfunction. OBJECTIVE: To determine the predictors of pulmonary dysfunction vis-à-vis the hypertension status of mine workers. METHODS: We conducted a cross-sectional study among 444 mine workers from ten open-cast mines in Gujarat state (western part of India) from November 2020 to February 2022. We collected data on demographics, occupation, addiction, and comorbidities, including measurements like anthropometry, blood pressure, blood sugar, haemoglobin, and lipid levels. Hypertension was confirmed based on self-reported history and/or onsite blood pressure measurement, while pulmonary functions were assessed using a spirometer (expressed as forced expiratory volume in the first second FEV1 and forced vital capacity FVC). Multiple linear regression analysis was performed to determine the significant predictor of FEV1 or FVC vis-à-vis the hypertension status after adjusting for confounding variables. In addition, we assessed the effect of anti-hypertensive medications on pulmonary dysfunction. RESULTS: A total of 41% (95% CI: 36-45%) of mine workers were suffering from hypertension. On multiple linear regression, only being a male and work experience duration were the significant predictors of FEV1 [0.900 (0.475-1.092), p=<0.001; -0.029 (-0.034 - -0.021, p=<0.001] and FVC [1.088 (0.771-1.404), p=<0.001; -0.031 (-0.038 - -0.024, p = 0.001] respectively. While unadjusted analysis indicated hypertension led to FEV1 and FVC reduction, this effect lost significance after adjusting for confounders. Nevertheless, subgroup analysis revealed those on antihypertensive medications had reductions in FEV1 and FVC by -0.263 (95% CI: -0.449 - -0.078, p = 0.006) L and -0.271 (95% CI: -0.476 - -0.067, p = 0.009) L respectively. CONCLUSION: In our study among mine workers, alterations in lung function (FEV1 and FVC) on spirometry were predicted by gender and duration of work experience, while hypertension did not serve as a predictor. It is noteworthy that antihypertensive drugs were found to reduce lung functions on spirometry, highlighting the need for further research.

Silicosis, progressive massive fibrosis and silico-tuberculosis among workers with occupational exposure to silica dusts in sandstone mines of Rajasthan state: An urgent need for initiating national silicosis control programme in India.

CONTEXT: Silicosis is a progressive, irreversible and incurable respiratory morbidity and often becomes a cause for pre-mature mortality among occupationally silica dust-exposed workers in India and similar countries. It has a dual problem of associated silico-tuberculosis as a co-morbidity. The present study was done to assess the respiratory morbidity caused by silicosis in sandstone mine of Rajasthan, India. METHODS: The chest X-rays of 529 subjects having history of employment in stone mines with respiratory morbidity were subjected for this study and evaluated in accordance with ILO Classification 2000. The X-rays were classified into various categories of silicosis and progressive massive fibrosis (PMF) in relation to years of work in stone mines. RESULTS: Out of 529 chest radiographs evaluated, 275 (52%) showed radiological evidence of silicosis. Of them, 40 (7.5%) subjects showed large opacities suggestive of progressive massive fibrosis. Both silicosis and progressive massive fibrosis were associated with increasing duration of work in stone mines. Sixty-one (12.4%) subjects with silicosis also had associated pulmonary tuberculosis, termed as silico-tuberculosis. CONCLUSION: The present study showed a high prevalence of silicosis, progressive massive fibrosis and silico-tuberculosis among stone mine workers. It appears that that unless silicosis is controlled, elimination of tuberculosis is far from reality in the country. Hence, states and central authorities must work together towards control of both silicosis as well as silico-tuberculosis. Similarly, there is an urgent need of initiation of national silicosis control programme, similar to existing national tuberculosis control programme, considering the huge burden of silicosis in India.

Respirable dust and crystalline silica exposure among different mining sectors in India.

Silicosis is one of the major occupational lung diseases among miners worldwide. The objective of this study was to characterize respirable dust and crystalline silica from limestone, iron, and bauxite mines in India. In total, 86 personal dust samples were collected from limestone (n = 30), iron (n = 30), and bauxite (n = 26) mines using dust sampler. The concentration of crystalline silica was analyzed using FTIR spectroscopy. Geometric mean respirable dust concentrations observed were 0.92, 1.08, and 1.07 mg/m3 for limestone, iron, and bauxite mines respectively, similarly for crystalline silica concentration observations were 0.015, 0.012 and 0.008 mg/m3 respectively. Among the three studied ores, mean crystalline silica concentration was statistically significant (p < 0.05) using an analysis of variance test. Although the detected levels of exposure are within the Indian exposure limits, attention should be paid to lower crystalline silica levels to minimize the risk of silicosis.

Risk assessment of chronic poisoning among Indian metallic miners.

The estimated average daily employment in the Indian mining sector is 5,60,000, which comprises 87% in the public sector and 13% in the private sector, of which around 70,000 are working in metallic mines. The mine workers are exposed to dust of various potentially toxic substances. The common toxicants present in the mining environment are lead, mercury, cadmium, manganese, aluminium, fluoride, arsenic, etc. Inhalation and absorption through the skin are common routes of exposure. Low-dose chronic exposure of toxic substances results in the accumulation of toxicants in the body. Hence, there is a need to monitor the mining environment as well as the miners for these toxicants.

Health survey in gypsum mines in India.

BACKGROUND: Mining is a hazardous occupation in which workers are exposed to adverse conditions. In India, gypsum mining is mainly carried out in the state of Rajasthan, which contributes about 99% of the total production. OBJECTIVE: The present study was carried out in 12 different gypsum mines in Rajasthan state to determine the health status of the miners. MATERIALS AND METHODS: One hundred and fifty workers engaged in mining activities were included in the study and their health status was compared with that of 83 office staff of the same mines. The health status of the employees was evaluated using a standardized medical questionnaire and pulmonary function testing. STATISTICAL ANALYSIS: The unpaired 't' test was used to determine whether there was any significant difference between the miners and the controls and the chi-square test to compare the prevalences of various respiratory impairments in workers with that in controls; we also examined the differences between smokers and nonsmokers. RESULTS: Our findings show that the literacy rate is low (42%) among the miners. Pulmonary restrictive impairment was significantly higher amongst smokers as compared to nonsmokers in both miners and controls. Hypertension (22.6%), diabetes (8.8%), and musculoskeletal morbidity (8%) were the common diseases in miners. CONCLUSION: This study shows that there is high morbidity amongst miners, thus indicating the need for regular health checkups, health education, use of personal protective devices, and engineering measures for control of the workplace environment.

Occupational noise-induced hearing loss in India.

Noise is the insidious of all industrial pollutants, involving every industry and causing severe hearing loss in every country in the world. Exposure to excessive noise is the major avoidable cause of permanent hearing impairment. Worldwide, 16% of the disabling hearing loss in adults is attributed to occupational noise, ranging from 7 to 21% in the various subregions. The estimated cost of noise to developed countries ranges from 0.2 to 2% of the gross domestic product (GDP). Noise-induced hearing loss (NIHL) is bilateral and symmetrical, usually affecting the higher frequencies (3k, 4k or 6k Hz) and then spreading to the lower frequencies (0.5k, 1k or 2k Hz). Other major health effects are lack of concentration, irritation, fatigue, headache, sleep disturbances, etc. The major industries responsible for excessive noise and exposing workers to hazardous levels of noise are textile, printing, saw mills, mining, etc. Hearing protectors should be used when engineering controls and work practices are not feasible for reducing noise exposure to safe levels. Earmuffs, ear plugs and ear canal caps are the main types of hearing protectors. In India, NIHL has been a compensable disease since 1948. It is only in 1996 that the first case got compensation. Awareness should be created among workers about the harmful effects of noise on hearing and other body systems by implementing compulsory education and training programs. There are very few published studies of NIHL in India. More extensive studies are needed to know the exact prevalence of NIHL among the various industries in India.