A study on occupational asthma among workers of silk filatures in South India

BACKGROUND: The production of silk is a multidimensional and multistep process involving exposure of workers to allergens at work place. The silk allergen has been implicated in the development of bronchial asthma. OBJECTIVES: To identify the prevalence of occupational asthma (OA) and to identify sensitization to silk allergen and among workers in silk filature units. MATERIALS AND METHODS: A community-based cross-sectional study was conducted in silk filature units of Ramanagara (Silk City) in Karnataka, South India, for a period of 6 months. One hundred and twenty workers of silk filature units who met the inclusion and exclusion criteria were recruited into the study group. For comparison, a control group comprising of 120 individuals not working in silk filature units was constituted. All the subjects were interviewed using the standardized International Union against Tuberculosis and Lung Diseases (IUATLD) Questionnaire and subjected to the skin prick test, which used the extracts of silk allergen. RESULTS: The study group comprised of 35 males and 85 females, whereas the control group comprised of 58 males and 62 females. The prevalence of occupational asthma among workers in silk filatures was 20.83%. It was observed that 35.83% of those in the study group and 20.83% of those in the control group were found to be sensitive to silk allergen. This difference was statistically significant (χ(2)= 6.64; P < 0.05). CONCLUSION: There is a high burden of sensitization to silk allergen and occupational asthma among silk filature workers in South India.