Spirometric Evaluation among Individuals Working in Stone Chip Crushing Factories: A Cross-sectional Study

Abstract

Introduction: Silicosis is still one of the most serious occupational health diseases in the world because of its potential to cause physical impairment. It is a progressive and debilitating occupational lung disease that primarily affects workers in the manufacturing, construction and mining industries. Silicosis is mostly caused by inhaling crystalline silica dust. Still, a substantial study on the lung health of stone quarry workers in Western Part of Bengal are still lacking. Aim: To determine the alterations in pulmonary function status (by spirometry) and evaluate the gender differences in pulmonary mechanics among workers affected by occupational silica dust. Materials and Methods: A cross-sectional study was conducted for a duration of three months to analyse the spirometric changes in lung function among 62 workers exposed to occupational silica dust, aged 18 to 60 years (both genders), attending the Department of Physiology at Rampurhat Government Medical College, West Bengal, India. After obtaining anthropometric measurements, including height and weight of the subjects, spirometry was carried out on each patient according to the recommendations of American Thoracic Society (ATS) and European Respiratory Society (ERS) (2005). Patients were grouped into categories of normal, Chronic Obstructive Pulmonary Disease (COPD), restrictive pattern, mixed ventilatory defect, and Small Airflow Obstruction (SAO) based on spirometric values of Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), FEV1/FVC, Forced mid-Expiratory Flow (FEF25%-75%), and Peak Expiratory Flow Rate (PEFR) values. Analysis was performed using GraphPad QuickCalcs software using Chi-square test and Unpaired t-test. Results: The mean age of the subjects was 49.6 years, with 51 (82.26%) males and 11 (17.74%) females among the 62 study subjects. There were 36 (58.06%) smokers and 26 (41.94%) non smokers. The average Body Mass Index (BMI) of the study subjects was 17.268±2.501 kg/m2 (underweight category). A significant reduction in spirometric variables was observed below the lower normal limit of percent predicted, including FVC (80-120%), FEV1 (80-120%), PEFR (>60% predicted value for men; up to 100 L/min lower than predicted for males, and 85 L/min for females), FEF25%-75% (50%-60% and up to 130% of the average), and Forced Expiratory Time (FET) (6 secs), except for the FEV1/FVC ratio (70-85%), which was higher than the normal limit. The majority of the study subjects belonged to the mixed ventilatory defect category, comprising 36 subjects (58.06%), 17 (27.42%) had a Restrictive Spirometric Pattern (RSP), while the remaining 9 subjects (14.52%) were classified as normal. Conclusion: Detectable spirometric changes have been observed among stone quarry workers, revealing not only restrictive patterns but also mixed ventilatory defects. Necessary preventive and interventional measures should be taken at an early phase to prevent further progression of lung impairment in such a population.

Keywords

• lung function test
• occupational silica dust
• mixed ventilatory defect