Cognitive decline following incident and preexisting diabetes mellitus in a population sample

Neurology. 2016 Oct 18;87(16):1681-1687. doi: 10.1212/WNL.0000000000003226. Epub 2016 Sep 21.


Objective: To examine if incident and preexisting diabetes mellitus (DM) were associated with cognitive decline among African Americans (AAs) and European Americans (EAs).

Methods: Based on a prospective study of 7,740 older adults (mean age 72.3 years, 64% AA, 63% female), DM was ascertained by hypoglycemic medication use and Medicare claims during physician or hospital visits, and cognition by performance on a brief battery for executive functioning, episodic memory, and Mini-Mental State Examination (MMSE). Decline in composite and individual tests among those with incident DM, with preexisting DM, and without DM was studied using a linear mixed effects model with and without change point.

Results: At baseline, 737 (15%) AAs and 269 (10%) EAs had preexisting DM. Another 721 (17%) AAs and 289 (12%) EAs had incident DM in old age. Following incident DM, cognitive decline increased by 36% among AAs and by 40% among EAs compared to those without DM. No significant difference was observed between AAs and EAs (p = 0.64). However, cognitive decline increased by 17% among AAs with preexisting DM compared to those without DM, but no increased decline was observed among EAs with preexisting DM. In secondary analyses, faster decline in executive functioning and episodic memory was observed following incident DM.

Conclusions: In old age, faster cognitive decline was present among AAs and EAs following incident DM, compared to cognitive decline prior to DM, and among those without DM. This underscores the need for stronger prevention and control of DM in old age.

MeSH terms

  • African Americans
  • Aged
  • Chicago
  • Cognition
  • Cognitive Dysfunction / complications*
  • Cognitive Dysfunction / ethnology*
  • Diabetes Complications / ethnology*
  • Diabetes Complications / psychology*
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / ethnology*
  • Diabetes Mellitus, Type 2 / psychology*
  • Disease Progression
  • European Continental Ancestry Group
  • Female
  • Follow-Up Studies
  • Humans
  • Hypoglycemic Agents / therapeutic use
  • Incidence
  • Linear Models
  • Longitudinal Studies
  • Male
  • Mental Status Schedule
  • Prospective Studies
  • Time Factors


  • Hypoglycemic Agents