Insulin Resistance and Central Nervous System (CNS) Function in Type 2 Diabetes

This study has been completed.
Information provided by:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Identifier:
First received: September 20, 2005
Last updated: February 12, 2010
Last verified: February 2010

The purpose of this study is to examine the effects of treating insulin resistance on memory and attention, brain glucose utilization, and proteins in spinal fluid.

Condition Intervention Phase
Insulin Resistance
Type 2 Diabetes Mellitus
Drug: pioglitazone
Drug: nateglinide
Drug: placebo
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double-Blind
Primary Purpose: Treatment

Resource links provided by NLM:

Further study details as provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):

Primary Outcome Measures:
  • Verbal memory (main study)
  • Selective attention (main study)
  • Plasma beta-amyloid levels (main study)
  • Cerebral glucose metabolism (sub-study)
  • Inflammatory markers in spinal fluid (sub-study)
  • Beta-amyloid in spinal fluid (sub-study)

Secondary Outcome Measures:
  • Psychomotor speed
  • Verbal fluency
  • Blood levels of insulin, insulin degrading enzyme, cortisol and inflammatory markers

Estimated Enrollment: 140
Study Start Date: November 2002
Study Completion Date: December 2006
Detailed Description:

Insulin resistant conditions such as impaired glucose tolerance, type 2 diabetes mellitus, and hyperinsulinemia have been associated with an increased risk for memory decline and for Alzheimer's disease. The main study will determine whether treatment with pioglitazone or nateglinide will improve verbal memory and selective attention for older adults with impaired glucose tolerance or mild type 2 diabetes. The main study will also characterize changes in blood concentrations of insulin, inflammatory markers, and the beta-amyloid peptides that are related to Alzheimer's disease. In one sub-study, participants will undergo brain positron emission tomography (PET) imaging before and after 16 weeks of treatment with pioglitazone, nateglinide, or placebo. The purpose of this sub-study is to determine the effects of treatment on brain glucose utilization. In a second sub-study, participants will undergo a lumbar puncture procedure before and after treatment. The purpose of this sub-study is to determine the effects of treatment on spinal fluid concentrations of insulin, inflammatory markers, and beta-amyloid peptides. Together these main and sub-studies should characterize the effects of insulin resistance on cognition and suggest a mechanism by which insulin resistant conditions increase risk for memory decline and for Alzheimer's disease.


Ages Eligible for Study:   55 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Impaired glucose tolerance OR mild type 2 diabetes mellitus OR normal blood sugar regulation
  • Stable weight and activity level

Exclusion Criteria:

  • Medications for diabetes
  • Dementia
  • Medications with known effects on memory
  • Serious neurologic disease or head trauma
  • Serious systemic illness (e.g., renal failure or uncontrolled hypertension)
  • Serious psychiatric illness (e.g., schizophrenia or bipolar disorder)
  • Allergy to pioglitazone or nateglinide
  Contacts and Locations
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Please refer to this study by its identifier: NCT00212290

United States, Washington
VA Puget Sound Health Care System (Seattle Campus)
Seattle, Washington, United States, 98108
VA Puget Sound Health Care System (American Lake Campus)
Tacoma, Washington, United States, 98493
Sponsors and Collaborators
Principal Investigator: Suzanne Craft, PhD VA Puget Sound Health Care System, University of Washington
  More Information

No publications provided Identifier: NCT00212290     History of Changes
Other Study ID Numbers: DK61606 (completed)
Study First Received: September 20, 2005
Last Updated: February 12, 2010
Health Authority: United States: Federal Government

Keywords provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):
impaired glucose tolerance

Additional relevant MeSH terms:
Diabetes Mellitus, Type 2
Insulin Resistance
Diabetes Mellitus
Endocrine System Diseases
Glucose Metabolism Disorders
Metabolic Diseases processed this record on August 27, 2015