RESUMO
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.
RESUMO
ABSTRACT Objective: Globally developing metabolic syndrome (MetS) prevalence as a major health problem can be related to multiple factors of genetic and environmental. Dimethylaminohydrolase 2 (DDAH2) is the main enzyme implicated in the cardiovascular system, which regulates the nitric oxide pathway. This study investigated the association of DDAH2 polymorphism −499C/G (rs805305) with the risk of MetS among the Azar-Cohort population. Subjects and methods: The occurrence of SNP rs805305 in the DDAH2 gene was tested using the PCR-RFLP method in 332 MetS cases and 294 healthy controls. Afterward, the association of the allele and genotypes with the risk of MetS and its components were examined. Results: The G allele and GC genotype were significantly associated with a reduced risk of MetS (P ≤ 0.001). Also, the dominant genetic model (GG+GC) significantly decreased the risk of MetS (P = 0.001), however, in sex subtypes MetS risk was significantly reduced in males before and in females after adjustment for age (P ≤ 0.02). Conclusion: The −499C/G polymorphism of DDAH2 may play a protective role and reduce MetS risk among the Azar-Cohort population.