Longitudinal Decline in Lung Function: Evaluation of Interleukin-10 Genetic Polymorphisms in Firefighters

Abstract

Learning Objectives 

• Recall whether and how, in this study of firefighters exposed to pulmonary toxicants, the rate of decline in one-second forced expiratory volume (FEV₁) is related to factors such as age, gender, race/ethnicity, smoking, and baseline FEV₁.
• Describe the relationship, if any, between the rate of decline in FEV₁ over time and genotypes for five single nucleotide polymorphisms in the gene for interleukin-10, a regulatory cytokine that suppresses proinflammatory mediators.
• Explain the possible implications of these findings for the accelerated loss of lung function observed in some—but not all—firefighters.

During annual medical monitoring, some firefighters are found to have rates of decline in forced expiratory volume in one second (FEV₁) far exceeding their peers. Interleukin-10 (IL-10) suppresses inflammation, and single nucleotide polymorphisms (SNPs) in the IL-10 gene may confer variable susceptibility to more rapid decline in lung function. In 1204 firefighters with at least six annual FEV₁ measurements, increased age and greater initial FEV₁ were associated with more rapid decline in lung function. DNA collected from 379 of these firefighters was screened for IL-10 SNPs at -1117, -854, 919, 1668, and 1812. A statistically significant difference in decline in lung function was found based on genotyping at the 1668 SNP. Evaluation of gene polymorphisms regulating lung inflammation may help to explain some of the variation in rate of decline in lung function in firefighters.