Investigating possible effects of aryl hydrocarbon receptor G1661A polymorphism on asthma severity in adults

Abstract

Aryl hydrocarbon Receptor (AhR) is a ligand-activated transcription factor with an important role in lung health. The association of AhR polymorphisms with asthma severity has not been yet investigated. We analyzed the association of G1661A, the most prevalent polymorphism of AhR, with the asthma stages in a population-based study including 555 asthmatics (Intermittent: 93, Mild: 240, Moderate: 158, and Severe: 64). The SNP was genotyped using allele-specific PCR. Obtained data were analyzed using the Generalized-Ordered Logit Estimates. Genotypes GA (OR: 0.53, CI: 0.32-0.90, P=0.019) and AA (OR: 0.22, CI: 0.06-0.76, P=0.017) were associated with decreased risk of Severe, Moderate, Mild vs. Intermittent stage; and Severe, Moderate, vs. Mild, Intermittent stages respectively. However, Genotype GA (OR: 1.90, CI: 1.05-3.44, P=0.033), dominant model GA+AA (OR: 2.04, CI: 1.17-3.57, P=0.012), and allele A (OR: 1.68, CI: 1.06-2.66, P=0.027) were associated with increased risk of Severe stage vs. Moderate, Mild, Intermittent stages. Also, male sex and higher age were associated with an increased odds ratio for severe asthma. Furthermore, significant associations with asthma stages were found for the interactions of the SNP and sex, smoking, and alcohol consumption. In conclusion, we revealed that the mutant allele of AhR-G1661A may interact with independent variables and act as a protective factor against lower stages of asthma but it may increase the risk of severe asthma.