Insulin resistance in cognitive impairment: the InCHIANTI study

Arch Neurol. 2005 Jul;62(7):1067-72. doi: 10.1001/archneur.62.7.1067.


Objective: To test the association between cognitive impairment, with and without subcortical features, and insulin resistance in an elderly community-dwelling population.

Design: Cross-sectional wave of an epidemiologic longitudinal study (InCHIANTI).

Participants: A total of 523 people, aged 70 to 90 years without diabetes mellitus or hyperglycemia, from the InCHIANTI cohort were included in the study. A total of 119 individuals had cognitive impairment (Mini-Mental State Examination [MMSE] score < 25), 21 of whom had both cognitive impairment and subcortical features (CI/SF+ group). Control groups contained 23 individuals with a history of stroke and 381 individuals with no cognitive impairment (no CI group, MMSE score > or = 25). Indicators of insulin resistance were the fasting plasma insulin level, insulin resistance index (Homeostasis Model Assessment of Insulin Resistance [HOMA-IR]), and insulin sensitivity index (Quantitative Insulin Sensitivity Check Index [QUICKI]).

Results: The insulin resistance profile of patients in the CI/SF+ group was similar to that of individuals who had experienced stroke, whereas the profile of individuals with cognitive impairment without subcortical features (CI/SF- group) was similar to that of individuals in the no CI group. Patients in the CI/SF- group showed insulin resistance comparable to individuals in the no CI group (age-adjusted P = .27, .19, and .64, respectively, for difference in fasting blood insulin level, HOMA-IR, and QUICKI in linear regression models) and lower than patients with stroke (age-adjusted P = .01, .02, and .07, respectively). On the contrary, patients in the CI/SF+ group had insulin resistance and sensitivity values similar to those of the stroke group (age-adjusted P = .80, .84, and .75, respectively, for difference in fasting blood insulin level, HOMA-IR, and QUICKI) but significantly different from those in the no CI group (age-adjusted P = .01, .03, and .02, respectively).

Conclusions: Cognitive impairment with but not without subcortical features is associated with biochemical and clinical features of insulin resistance syndrome. In epidemiologic populations, insulin resistance might contribute to cognitive impairment through a vascular mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Cognition Disorders / epidemiology*
  • Cognition Disorders / physiopathology*
  • Cross-Sectional Studies
  • Epidemiologic Studies
  • Humans
  • Insulin Resistance*
  • Male
  • Mental Status Schedule