Bronchial asthma among workers in Alexandria and its association with occupation, eosinophil count, total serum immunoglobulin E antibodies, and glutathione S-transferase genes polymorphism

Possible association of a distinct combined Glutathione-S-transferase members with allergic asthma patients in Pakistan

Allergic asthma is a diverse chronic respiratory disease characterized by the inflammation of the lower airway disease affecting many people around the world with rising morbidity and mortality. Association between asthma and certain demographic features was studied in relation to genotype from 244 allergic individuals of local population. Skin prick test was used to confirm asthma. Genetic polymorphism in Glutathione-S-transferases (GSTs) was studied using multiplex PCR based method and IgE level by ELISA. Pollen and dust were the major causative aeroallergens (26%), which were associated to higher IgE levels (P < 0.05). Smoking was found to be significantly associated with asthma in only males (P = 0.004). A low prevalence of null genotype of both GSTM1 and GSTT1 genes was observed in the patients (4.34%) compared to control group (14%). No association of combined GSTM1 and GSTT1 null genotype was found with the asthma in local population. GSTM1+ and GSTT− genotype had higher risk (OR = 1.3681, P = 0.001) for development of asthma. There was a significant association of asthma with combined genotype of GSTM1+ and GSTT− when data was analyzed on gender basis in males (P = 0.006) and highly significant in age range of 26–40 years (P = 0.001). Combined GSTM⁺ and GSTT⁻ genotype was found to be risk factor for asthma in addition to family history in male patients. However a data with large patient size and different ethnic distribution may reveal the exact etiology.

Significant association between asthma risk and the GSTM1 and GSTT1 deletion polymorphisms: an updated meta-analysis of case-control studies

Polymorphisms in GSTM1 and GSTT1 may be associated with asthma risk, yet several studies and meta-analyses have reported inconclusive results. Therefore, an updated meta-analysis was conducted. Literature searches were performed using the Pubmed, Embase and Web of Science databases until October 2012. Variant 'null' genotype was compared with wild-type 'present' in the pooled data. All statistical analyses were performed using STATA 11.0. A total of 26 case-control studies were suitable for inclusion in the meta-analysis. In the overall population, a significant association was found for both the GSTM1 (odds ratio (OR) = 1.452; 95% confidence interval (CI): 1.192-1.770) and GSTT1 polymorphism (OR = 1.792; 95% CI:1.293-2.483). For subgroup analysis by age, GSTM1 significantly increased risk for both children (OR = 1.368; 95% CI: 1.051-1.781) and adults (OR = 1.859; 95% CI: 1.183-2.921). For GSTT1, a significant association was only found in the adult population (OR = 2.312; 95%CI: 1.204-4.439). Based on subgroup analysis by ethnicity, a significant association for GSTM1 was found in Europe (OR = 1.303; 95% CI: 1.018-1.667), Africa (OR = 2.175; 95%CI: 1.560-3.031) and Latin America (OR = 2.265; 95%CI: 1.375-3.729). For GSTT1, significantly increased risk was found only for Asian (OR = 2.105; 95% CI: 1.101-4.025) and Russian (OR = 2.747; 95% CI: 1.071-7.046) populations. This meta-analysis provides evidence that GSTM1 and GSTT1 polymorphisms may be risk factors for asthma.