Genetic polymorphisms of exon 1 of MBL2 contribute to tuberculosis risk especially in Asian populations: an updated meta-analysis of 26 studies

BACKGROUND: Evidence suggests that genetic variations of exon 1 of mannose-binding lectin 2 (MBL2) may contribute to tuberculosis (TB) risk. Many studies have investigated the association between MBL2 exon 1 polymorphisms (rs1800450, rs1800451, and rs5030737) and TB risk, but yielded inconclusive results. METHOD: We conducted this meta-analysis of 26 eligible case–control studies that included 7952 cases and 9328 controls to identify the strength of association. Odds ratio (OR) and 95% CI were used to evaluate the strength of association. Statistical analyses were performed by using STATA 12.1. RESULTS: We found a statistically significant correlation between MBL2 exon 1 polymorphisms and increased TB risk among three models: allele model (O vs A: OR =1.18, 95% CI: 1.01–1.38, P(heterogeneity)<0.0001, I(2)=85.8%), homozygote comparison (OO vs AA: OR =1.49, 95%CI: 1.02–2.18, P(heterogeneity)<0.0001, I(2)=79.1%), dominant model (AO/OO vs AA: OR =1.20, 95% CI: 1.01–1.43, P(heterogeneity)<0.0001, I(2)=83.5%), especially in studies based on Asian populations among five models: allele model (O vs A: OR =1.29, 95% CI: 1.11–1.51, P(heterogeneity)<0.0001, I(2)=66.0%), homozygote comparison (OO vs AA: OR =1.67, 95% CI: 1.09–2.55, P(heterogeneity)=0.008, I(2)=54.2%), heterozygote comparison (AO vs AA: OR =1.26, 95% CI: 1.05–1.50, P(heterogeneity)=0.001, I(2)=62.9%), dominant model (AO/OO vs. AA: OR =1.31, 95% CI: 1.10–1.56, P(heterogeneity)=0.001, I(2)=64.2%), and recessive model (OO vs AO/AA: OR =1.50, 95% CI: 1.01–2.22, P(heterogeneity)=0.023, I(2)=48.0%). Meta-regression results revealed that source of controls (p=0.009), but not ethnicity (p=0.687), genotyping method (p=0.231), and sample size (p=0.451) contributed to the source of heterogeneity. CONCLUSION: This meta-analysis suggests that MBL2 exon 1 polymorphisms may contribute to TB risk, especially in Asian populations.