title: Diabetes, glycaemia, and cognition-a secondary analysis of the Finnish Diabetes Prevention Study.
abstract: BACKGROUND
  Type 2 diabetes is linked with cognitive dysfunction and dementia in epidemiological studies, but these observations are limited by lack of data on the exact timing of diabetes onset. We investigated diabetes, dysglycaemia, and cognition in the Finnish Diabetes Prevention Study, in which the timing and duration of diabetes are well documented.
  
  
  METHODS
  The Finnish Diabetes Prevention Study comprised middle-aged, overweight participants with impaired glucose tolerance but no diabetes at baseline (n = 522), randomized to lifestyle intervention or a control group. After an intervention period (mean duration 4 years) and follow-up (additional 9 years), cognitive assessment with the CERAD test battery and Trail Making Test A (TMT) was executed twice within a 2-year interval. Of the 364 (70%) participants with cognitive assessments, 171 (47%) had developed diabetes.
  
  
  RESULTS
  Cognitive function did not differ between those who developed diabetes and those who did not. Lower mean 2-h glucose at an oral glucose tolerance test (OGTT) and HbA1C during the intervention period predicted better performance in the TMT (p = 0.012 and 0.024, respectively). Those without diabetes or with short duration of diabetes improved in CERAD total score between the two assessments (p = 0.001) whereas those with long duration of diabetes did not (p = 0.844).
  
  
  CONCLUSIONS
  Better glycemic control among persons with baseline impaired glucose tolerance predicted better cognitive performance 9 years later in this secondary analysis of the Finnish Diabetes Prevention Study population. In addition, learning effects in cognitive testing were not evident in people with long diabetes duration. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Department of Public Health, University of Helsinki, Finland.
authors.forename: Jenni
authors.identifier: http://orcid.org/0000-0002-8818-0848
authors.initials: J
authors.lastname: Lehtisalo
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Jaana
authors.initials: J
authors.lastname: Lindström
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Tiia
authors.initials: T
authors.lastname: Ngandu
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Aging Research Center, Karolinska Institutet, Stockholm, Sweden.|Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
authors.forename: Miia
authors.initials: M
authors.lastname: Kivipelto
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Espoo City Hospital, Espoo, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Ahtiluoto
authors.affiliation: Science Center, Tampere University Hospital, Tampere, Finland.|The Diabetes Center, Finnish Diabetes Association, Tampere, Finland.
authors.forename: Pirjo
authors.initials: P
authors.lastname: Ilanne-Parikka
authors.affiliation: Institute of Health Sciences (General Practice), University of Oulu, Oulu, Finland.|Unit of General Practice, Oulu University Hospital and Health Centre of Oulu, Oulu, Finland.
authors.forename: Sirkka
authors.initials: S
authors.lastname: Keinänen-Kiukaanniemi
authors.affiliation: Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Department of General Practice and Primary Health Care, University of Helsinki, Finland.|Folkhälsan Research Center, Helsinki, Finland.|Unit of General Practice, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Johan G
authors.initials: JG
authors.lastname: Eriksson
authors.affiliation: Institute of Public Health and Clinical Nutrition, Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.|Research Unit, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Uusitupa
authors.affiliation: Center for Vascular Prevention, Danube University Krems, Krems, Austria.|Instituto de Investigacion Sanitaria del Hospital Universario LaPaz (IdiPAZ), Madrid, Spain.|Diabetes Research Group, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
authors.affiliation: Department of Medicine, Columbia University Medical Center, NY, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Luchsinger
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000375:Aging; D015992:Body Mass Index; D060825:Cognitive Dysfunction / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control; D015331:Cohort Studies; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology / Q000517:prevention & control; D018450:Disease Progression; D057239:Early Termination of Clinical Trials; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D008019:Life Style; D050177:Overweight / Q000150:complications / Q000628:therapy; D010349:Patient Compliance; D011236:Prediabetic State / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D012307:Risk Factors
keywords: cognition; dysglycaemia; type 2 diabetes