The association of transforming growth factor-β1 (TGF-β1) polymorphisms with the risk of chronic kidney diseases (CKD) remains elusive. We aimed to perform a meta-analysis to evaluate the relationship between TGF-β1 polymorphisms and the susceptibility to CKD. Association studies were searched according to a defined criteria using electronic databases. The strength of association between TGF-β1 polymorphisms and CKD risk was evaluated by odds ratio (OR) with the corresponding 95% confidence interval (CI). Nine case-control studies were identified. T allele at the +869 T/C polymorphism was associated with a lower risk of CKD in Asians (p = 0.003). TT genotype at the +869 T/C polymorphism was associated with a lower risk of CKD in overall populations and Asians (p = 0.007 and <10(-4), respectively). CC genotype at the +869 T/C polymorphism was associated with the risk of CKD in Asians (p = 0.002). T allele at the -509 T/C polymorphism was associated with the risk of CKD in overall populations and Asians (p = 0.044 and 0.050, respectively). TT genotype at the -509 T/C polymorphism was associated with CKD risk in overall populations, Caucasians and Asians (p < 10(-4), <10(-4), and <10(-4), respectively). No evidence of significant publication bias was noted. In conclusion, T allele at the +869 T/C polymorphism may be a protective factor against CKD risk in Asians. TT genotype at the +869 T/C polymorphism may be an indicator of lower risk of CKD in overall populations and Asians. CC genotype at the +869 T/C polymorphism may predict the susceptibility to CKD in Asians. T allele at the -509 T/C polymorphism may be an indicator of CKD risk in overall populations and Asians. TT genotype at the -509 T/C polymorphism was a risk factor for CKD onset in overall populations, Caucasians and Asians.
Keywords: Chronic kidney diseases; gene polymorphisms; meta-analysis; transforming growth factor-β1.