Association of type 2 diabetes mellitus and its management with cognitive function in adults: A prospective cohort study

Abstract Background Type 2 Diabetes Mellitus (T2DM) has been associated with lower levels of cognitive function in older adults. However, evidence on the potential role of T2DM management in age‐related cognitive function is limited. To explore the prospective association of T2DM and its management with cognitive function among middle‐aged and older Chinese adults. Method This study included 7,230 participants without baseline brain damage, mental retardation, or memory‐related diseases from the China Health and Retirement Longitudinal Study (CHARLS) in 2011‐2012. Fasting plasma glucose and self‐reported information on T2DM diagnosis and treatment was assessed at baseline. Participants were then categorized into normoglycemia, impaired fasting glucose (IFG), and T2DM (including untreated T2DM and treated T2DM) groups. Cognitive function, including episodic memory and executive function, was assessed by the modified Telephone Interview for Cognitive Status (TICS) every two years until 2015. We used the generalized estimating equation (GEE) model to examine the association of baseline T2DM status and cognitive function in succeeding years. Result Compared to those with normoglycemia, participants with T2DM tended to have lower level of overall cognitive function (β = ‐0.23, 95% CI: ‐0.43, ‐0.02) after controlling for demographic variables, lifestyles, follow‐up time, and major clinical factors. In particular, the strong association was mainly observed for those with untreated T2DM (β = ‐0.31, 95% CI: ‐0.54, ‐0.07), especially in the domain of executive function (β = ‐0.22, 95% CI: ‐0.39, ‐0.06) and among those ≥60 years (β = ‐0.58, 95% CI: ‐0.91, ‐0.23). In general, individuals with IFG and treated T2DM had similar levels of cognitive function with normoglycemia participants. Conclusion Our findings supported the detrimental role of T2DM especially untreated T2DM in cognitive function among middle‐aged and older adults. Screening and early treatment for T2DM are warranted for maintaining better cognitive function in later life.