Assessment of Respiratory Function and Exercise Capacity Among Persons Having Occupational Exposure to Silica Dust

Abstract

Background: Silica inhalation at the workplace remains a major public health concern, particularly in developing countries where large numbers of workers are engaged in mining, stone crushing, stone cutting, and drilling activities. Prolonged inhalation of silica dust can result in progressive pulmonary fibrosis, leading to deterioration in lung function and a decline in exercise capacity. While radiological assessment plays an important role in disease evaluation, measurements of pulmonary function and functional exercise capacity provide additional insight into the physiological impact and severity of silica-related lung disease.
Methods: Workers exposed to silica dust were selected as study subjects over the time period of two years. Clinical history and examination in detail, along with chest radiography, spirometry, and six-minute walk test (6MWT), etc were done and results were correlated with chest x-ray findings.
Results: The mean age of participants was 47.19 ± 11.18 years, and 78.08% were male. The mean duration of silica exposure was 14.64 ± 6.76 years, with 68.49% exposed for more than 10 years. Dyspnoea (98.63%) and cough (93.15%) were the predominant symptoms. Mean pre-bronchodilator FEV₁ and FVC were 46.32 ± 17.35% and 52.15 ± 16.54%, respectively, indicating severe ventilatory impairment. The mean six-minute walk distance was 263.41 ± 94.88 meters, with significant exercise-induced oxygen desaturation from 95.11 ± 1.66% to 92.34 ± 2.61%. Chest radiographic severity showed significant correlations with spirometric impairment (p <0.001), and reduced exercise capacity (p <0.001).
Conclusion: Workers exposed to silica dust demonstrate significant impairment of respiratory function and exercise capacity. Pulmonary function testing and six-minute walk testing are valuable tools for assessing disease burden and should be incorporated into routine occupational health surveillance programs.