342-OR: The Impact of Insulin Secretion and Insulin Sensitivity on Cognition in Adults with Prediabetes—The Diabetes Prevention Program Outcomes Study (DPPOS)

Abstract

Dysglycemia is a significant risk factor for cognitive impairment. However, which pathophysiologic determinant of dysglycemia, impaired insulin sensitivity (ISens) or insulin secretion (ISecr), or both, contributes to poorer cognitive function is not established. Among 1,054 adults with prediabetes (PreD) from the DPPOS, who did not develop diabetes, we investigated the relationship between ISecr, ISens and cognitive function, hypothesizing that lower ISens and/or lower ISecr is associated with worse cognition. Early ISecr was estimated by the mean insulinogenic index (IGI; pmol/mmol) from repeated annual oral glucose tolerance tests and ISens was estimated by the mean 1/fasting insulin from repeated fasting blood draws. ISecr and ISens were calculated over approximately 12 years of follow-up. Verbal learning (Spanish-English Verbal Learning Test [SEVLT]) and processing speed (Digital Symbol Substitution Test [DSST]) were assessed at the end of the follow-up period. Separate linear regression models were run for each cognitive outcome. Models included both mean ISecr and mean ISens as the main predictor variables and were adjusted for demographic, lifestyle, cardiovascular factors, and medications. Contrary to our hypothesis and to prior studies, higher mean ISecr was associated with poorer performance on the DSST (-0.74 points per SD increase in IGI, 95% CI: -1.43, -0.05; p=0.03). Mean ISens was not associated with DSST, nor were mean ISecr or mean ISens associated with SEVLT. These results suggest that higher insulin secretion in people with longstanding PreD may negatively impact processing speed, a critical component of executive control. This relationship could reflect a compensatory response of insulin in people with worsening metabolic dysregulation, who may also have poorer cognition. Further study is needed to replicate these findings and to understand the role of insulin in cognitive function. Disclosure A. Shapiro: None. A.H. Tjaden: None. S. Edelstein: None. S.E. Kahn: Advisory Panel; Anji Pharmaceuticals, Bayer Inc., Boehringer Ingelheim Inc., Eli Lilly and Company, Merck & Co., Inc. Other Relationship; Novo Nordisk. P. Srikanthan: None. W.C. Knowler: None. E.M. Venditti: None. S. Golden: Advisory Panel; Abbott Diabetes, Medtronic. O. Carmichael: Research Support; Eli Lilly and Company. Advisory Panel; Novo Nordisk. Research Support; Nestlé Health Science. K.M. Gadde: Research Support; BioKier, Inc., National Institute of Diabetes and Digestive and Kidney Diseases. J.A. Luchsinger: Consultant; Merck KGaA. Other Relationship; Wolters Kluwer Health. D. Research Group: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (UDK048489, UDK048339, UDK048377, UDK048349, UDK048381, UDK048468, UDK048434, UDK048485, UDK048375, UDK048514, UDK048437, UDK048413, UDK048411, UDK048406, UDK048380, UDK048397, UDK048412, UDK048404, UDK048387, UDK048407, UDK048443, UDK048400)