CTLA-4+49A/G gene polymorphism and type 1 diabetes mellitus in the Chinese population: a meta-analysis of 2238 subjects

Previous studies reported that cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) +49A/G gene polymorphism is correlated with type 1 diabetes mellitus (T1DM) risk. However, their results remain disputable. This study aims to discuss the relationship between CTLA-4 +49A/G gene polymorphism and T1DM in a Chinese population. The current meta-analysis involved 2238 participants from seven individual studies. The pooled odds ratio (OR) and its corresponding 95 % confidence interval (95 % CI) were assessed by the random- or fixed-effects model. A significant relationship between CTLA-4 +49A/G gene polymorphism and T1DM was detected under allelic (OR: 1.84, 95 % CI: 1.62-2.10, P < 0.00001), dominant (OR: 1.152, 95 % CI: 1.062-1.249, P = 0.001), recessive (OR: 1.631, 95 % CI: 1.443-1.844, P < 0.00001), and additive (OR: 1.292, 95 % CI: 1.224-1.363, P < 0.00001) genetic models. A significant relationship exists between CTLA-4 +49A/G gene polymorphism and increased T1DM risk in the Chinese population. Individuals having the G allele of CTLA-4 +49A/G gene polymorphism have a higher risk for T1DM in the Chinese population.