ObjectiveTo systematically evaluate the association between MTHFR gene C677T polymorphism and susceptibility to young and middle-aged adult ischemic stroke among Chinese population. MethodsSuch databases as PubMed, EMbase, The Cochrane Library (Issue 11, 2013), CBM, CNKI, VIP and WanFang Data were systemically searched to collect case-control studies published from Jan 1990 to Dec 2013. RevMan 5.2 was used to quantitatively analyzed the qualified and included studies, the pooled odds ratio (ORs) with 95% confidence interval (CI) were calculated; Stata 12.0 software were used for sensitivity and publication bias analysis. ResultsA total of 10 studies were included, which involved 787 cases and 766 controls. The results of meta-analysis showed that, in overall young and middle-aged adult group (aged less than 60), individuals that carried T allele risked more with ischemic stroke than those carried C allele (OR=1.42, 95%CI 1.07 to 1.89, P=0.02); more susceptibility to ischemic stroke was found among people of TT genotype compared with those of CC genotype (OR=2.11, 95%CI 1.58 to 2.81, P=0.00), as well as those of TT+TC genotype compared with CC genotype (OR=1.97, 95%CI 1.55 to 2.51, P=0.00), and those of TT genotype compared with TC+CC genotype (OR=1.42, 95%CI 1.13 to 1.77, P=0.00). Increased risk was also observed in TT+TC genotype compared with CC genotype in young adult subgroup (aged less than 45) (OR=1.66, 95%CI 1.19 to 2.32, P=0.00). ConclusionMTHFR gene C677T polymorphism is significantly associated with susceptibility to young and middle-aged adult ischemic stroke among Chinese population, and more risk may exist in middle-aged adult population.