CD4 and type 2 diabetes mellitus: IL20RA, IgD- CD38dim B cells, HLA DR+ CD4+ T cells, and CD3 on effector memory CD4+ T cells emerged as candidate mediators of the observed causal links.<h4>Conclusion</h4>Our study uncovers causal associations between T2D and its complications with cortical structure, highlighting the cingulate's particular vulnerability.