The present meta-analysis aimed to evaluate the interaction between type 2 diabetes mellitus (T2DM) and the risk of cognitive impairment. The studies that fulfilled certain inclusion criteria were selected from online databases including PubMed, Embase, and the Cochrane Library. Data extraction and quality assessment were conducted, and subgroup analysis was performed according to the study area, population sources, and types of cognitive impairment. Publication bias and sensitivity analysis were evaluated. In total, 30 studies from 25 articles, including 2 case-control studies, 9 cohort studies, and 19 cross-sectional studies, were included. Subgroup analysis showed that despite the presence of hospital-based and multi-center subgroups in the cohort studies, the association between T2DM and cognitive impairment risk was statistically significant in all other subgroups (P < 0.05). Furthermore, the sensitivity and publication bias analysis showed good stability in all enrolled studies. T2DM might be associated with the risk of cognitive impairment. Further studies on early detection and appropriate management of cognitive impairment might be required in T2DM patients of different regions.
