Pattern and predictors of mortality in sandstone quarry workers

Study of silicosis was conducted in 1992-1994, which included a sample of 458 sandstone quarry workers of Jodhpur. To find out the pattern and predictors of mortality among sandstone quarry workers. Houses of all workers were visited and the worker′s status was recorded. Standardized mortality ratio (for all causes of death) was calculated. Cox proportional hazard model was applied to study the association of different variables with mortality. Total 97.8% workers could be followed, of whom, 10.9% had died (SMR = 1.72; 95% CI 1.23 - 2.19). The average age at the time of death of the deceased was 51.8 ± 12.5 years. Mortality was higher among silicotics (SMR = 2.54; 95% CI 1.43 - 3.66), smokers (SMR = 1.83; 95% CI 1.27 - 2.39), and those showing mixed abnormality in pulmonary function test (SMR = 2.73; 95% CI 1.24 - 4.21). In multivariate Cox proportional hazard model, restriction in spirometery (HR = 13.95; 95% CI 9.14 - 21.29), longer duration (> 15 years) of working in quarries (HR = 7.29; 95% CI 5.19 - 10.24), chronic dyspnoea (HR = 6.48; 95% CI 4.70 - 8.95), silicosis (HR = 6.03; 95% CI 4.85 - 7.51), BMI < 1.75 (HR = 3.50; 95% CI 2.78 - 4.41), and chronic chest pain (HR = 3.28; 95% CI 2.51 - 4.28) emerged as significant predictors of all cause mortality.
It can be concluded that sandstone quarry workers died at a younger age. In absence of certified cause of death, these predictors suggest that silicosis, COPD, lung cancer, and tuberculosis might be underlying causes of higher mortality. This study underlines the need for adopting measures among workers for the prevention from exposure to fine dust.