Student Research: Austin Summer
, Occupational Medicine (Occ Med), 2004
Faculty Advisor: Timothy K. Takaro
Is GSTM1 Related to Pulmonary Fibrosis in Asbestos Exposed Workers?
Background: Asbestos continues to be a public health problem today. There does not appear to be an equal dose response across all individuals exposed to asbestos. Host susceptibility must be important in determining who will develop asbestos related disease. Glutathione S-transferases (GST) are a family of conjugating enzymes that catalyze the detoxification of a variety of potentially cytotoxic electrophilic agents. The glutathione S- transferase Mu class in humans is polymorphic. A cross sectional study using 220 subjects from asbestos and lung cancer study will be used to identify an association between GSTM1 null genotype and asbestos related pulmonary disease.
Methods: The 220 study subjects were selected from the Beta-Carotene and Retinol Efficacy Trail (CARET) cohort due to the availability of polymorphism data, lung function (spirometry) and chest x-ray data. The 220 subjects were divided into 2 groups based on GSTM1 presence or deletion and compared by baseline CARET entry ILO scores and spirometry.
Results: Of the 220 subjects 111 subjects had the GSTM1 gene and 109 have the gene deletion. There was no statistically significant difference in the frequency of pulmonary fibrosis, ILO score >=1/0, and restrictive or mixed pattern on spirometry by polymorphism. No association was found between polymorphism and changes on chest x-ray or lung function after adjusting of age, smoking, years of asbestos exposure, and years in high risk trade using the logistic regression model.
Conclusion: This study was unable to demonstrate an association between GSTM1 polymorphism and pulmonary changes resulting from asbestos exposure. This sampled lacked sufficient power to determine a difference less than a relative risk of 2. This study agrees with the other reports with similar exposure assessment.