Elevated HbA_1c is Associated with Increased Risk of Incident Dementia in Primary Care Patients

Article type: Research Article

Authors: Ramirez, Alfredo^{a; b; 1; *} | Wolfsgruber, Steffen^{a; c; 1} | Lange, Carolin^d | Kaduszkiewicz, Hanna^d | Weyerer, Siegfried^e | Werle, Jochen^e | Pentzek, Michael^f | Fuchs, Angela^f | Riedel-Heller, Steffi G.^g | Luck, Tobias^{g; h} | Mösch, Edelgardⁱ | Bickel, Horstⁱ | Wiese, Birgitt^j | Prokein, Jana^j | König, Hans-Helmut^k | Brettschneider, Christian^k | Breteler, Monique M.^c | Maier, Wolfgang^{a; c} | Jessen, Frank^{a; c; 2} | Scherer, Martin^{d; 2} | for the AgeCoDe Study Group

Affiliations: [a] Department of Psychiatry and Psychotherapy, University of Bonn, Bonn, Germany | [b] Institute of Human Genetic, University of Bonn, Bonn, Germany | [c] German Center for Neurodegenerative Disorders (DZNE, Bonn), Bonn, Germany | [d] Department of Primary Medical Care, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany | [e] Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany | [f] Institute of General Practice, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany | [g] Institute of Social Medicine, Occupational Health and Public Health, University of Leipzig, Leipzig, Germany | [h] LIFE – Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany | [i] Department of Psychiatry, Technische Universität München, Klinikum rechts der Isar, Munich, Germany | [j] Institute of Biometrics, Hannover Medical School, Hannover, Germany | [k] Department of Medical Sociology and Health Economics, Hamburg Center for Health Economics, University Medical Center Hamburg, Hamburg, Germany

Correspondence: [*] Correspondence to: Alfredo Ramirez, MD, Department of Psychiatry and Psychotherapy, University of Bonn, Sigmund-Freud-Strasse 25, D-53105, Bonn, Germany. Tel.: +490 228 287 19323; Fax: +490 228287 16097; E-mail: alfredo.ramirez@ukb.uni-bonn.de.

Note: [1] These authors contributed equally to this work.

Note: [2] Shared last authors.

Abstract: Type 2 diabetes mellitus (T2DM) is a risk factor of dementia. The effect of T2DM treatment quality on dementia risk, however, is unclear. 1,342 elderly individuals recruited via general practitioner registries (AgeCoDe cohort) were analyzed. This study analyzed the association between HbA1c level and the incidence of all-cause dementia (ACD) and of Alzheimer's disease dementia (referred to here as AD). HbA1c levels ≥6.5% were associated with 2.8-fold increased risk of incident ACD (p = 0.027) and for AD (p = 0.047). HbA1c levels ≥7% were associated with a five-fold increased risk of incident ACD (p = 0.001) and 4.7-fold increased risk of incident AD (p = 0.004). The T2DM diagnosis per se did not increase the risk of either ACD or AD. Higher levels of HbA1c are associated with increased risk of ACD and AD in an elderly population. T2DM diagnosis was not associated with increased risk if HbA1c levels were below 7%.

Keywords: Alzheimer's disease, diabetes mellitus, epidemiology, glycosylated hemoglobin, incident dementia

DOI: 10.3233/JAD-141521

Journal: Journal of Alzheimer's Disease, vol. 44, no. 4, pp. 1203-1212, 2015