Quantitative Assessment of the Association Between the GSTM1-Null Genotype and the Risk of Childhood Asthma

Abstract

Many studies investigated the association between the glutathione S-transferase M 1 (GSTM1)-null genotype and childhood asthma risk, but there was obvious inconsistence among those studies. The aim of this meta-analysis was to quantify the strength of association between the GSTM1-null genotype and risk of childhood asthma. We searched the PubMed, Embase, and Wangfang databases for studies relating the association between the GSTM1-null genotype and risk of childhood asthma. We estimated the pooled odds ratio (OR) with its 95% confidence interval (95% CI) to assess the association. Nineteen case-control studies with 4,543 childhood asthma cases and 19,394 controls were included into this meta-analysis. Meta-analysis of all 19 studies showed that the GSTM1-null genotype was associated with increased risk of childhood asthma (OR=1.17, 95% CI 1.03-1.34, p=0.017). Subgroup analyses by ethnicity suggested that the GSTM1-null genotype was associated with an increased risk of childhood asthma in Caucasians and Africans (for Caucasians, fixed-effects OR=1.16, 95% CI 1.07-1.27, p=0.001; for Africans, fixed-effects OR=1.92, 95% CI 1.35-2.74, p<0.001). The cumulative meta-analyses showed a trend of obvious association between the GSTM1-null genotype and risk of childhood asthma as information accumulated in the analyses of both total studies and Caucasians. No evidence of publication bias was observed. Meta-analyses of available data suggest a significant association between the GSTM1-null genotype and the risk of childhood asthma, and the GSTM1-null genotype contributes to increased risk of childhood asthma, especially in Caucasians and Africans.