Insulin Resistance Predicts Cognitive Decline: An 11-Year Follow-up of a Nationally Representative Adult Population Sample

• Published in: Diabetes care Vol. 40; no. 6; pp. 751 - 758
• Main Authors: Ekblad, Laura L, Rinne, Juha O, Puukka, Pauli, Laine, Hanna, Ahtiluoto, Satu, Sulkava, Raimo, Viitanen, Matti, Jula, Antti
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01.06.2017
• Subjects: Adult; Aged; Aged, 80 and over; Apolipoprotein E4; Apolipoprotein E4 - blood; Blood Glucose - metabolism; Cognition; Cognition & reasoning; Cognitive ability; Cognitive Dysfunction - blood; Cognitive Dysfunction - diagnosis; Cohort Studies; Diabetes; Diabetes mellitus; Diabetes Mellitus, Type 2 - blood; Fasting; Female; Finland; Follow-Up Studies; Glucose; Glycated Hemoglobin A - metabolism; Health; Humans; Insulin; Insulin - blood; Insulin Resistance; Learning; Linear Models; Male; Medicin och hälsovetenskap; Middle Aged; Multivariate Analysis; Recall; Regression analysis; Research design; Risk analysis; Risk Factors
• ISSN: 0149-5992; 1935-5548; 1935-5548
• DOI: 10.2337/dc16-2001

The aim of this study was to examine whether insulin resistance, assessed by HOMA of insulin resistance (HOMA-IR), is an independent predictor of cognitive decline. The roles of HOMA-IR, fasting insulin and glucose, HbA , and hs-CRP as predictors of cognitive performance and its change were evaluated in the Finnish nationwide, population-based Health 2000 Health Examination Survey and its 11-year follow-up, the Health 2011 study ( = 3,695, mean age at baseline 49.3 years, 55.5% women). Categorical verbal fluency, word-list learning, and word-list delayed recall were used as measures of cognitive function. Multivariate linear regression analysis was performed and adjusted for previously reported risk factors for cognitive decline. Higher baseline HOMA-IR and fasting insulin levels were independent predictors of poorer verbal fluency performance ( = 0.0002 for both) and of a greater decline in verbal fluency during the follow-up time ( = 0.004 for both). Baseline HOMA-IR and insulin did not predict word-list learning or word-list delayed recall scores. There were no interactions between HOMA-IR and apolipoprotein E ε4 ( ) genotype, hs-CRP, or type 2 diabetes on the cognitive tests. Fasting glucose and hs-CRP levels at baseline were not associated with cognitive functioning. Our results show that higher serum fasting insulin and insulin resistance predict poorer verbal fluency and a steeper decline in verbal fluency during 11 years in a representative sample of an adult population. Prevention and treatment of insulin resistance might help reduce cognitive decline later in life.