Diabetes Linked to Cognitive Problems
Severe or Long-Term Diabetes Increases Risk of Memory Problems
Aug. 12, 2008 -- Adults who have severe or long-term diabetes or who develop the disease before age 65 have an
increased risk of mild but noticeable memory problems.
Researchers reporting in the August issue of Archives of Neurology have
linked mild cognitive impairment to earlier onset, longer duration, and greater
severity of diabetes.
Mild cognitive impairment is a condition marked by mild forgetfulness, language
difficulties, and other cognitive problems that are noticeable but do not
interfere with everyday tasks. It is considered a transition stage between
normal aging and dementia (including Alzheimer's disease), according to the journal
The new findings confirm results from previous studies, which have suggested an
association between diabetes and declining cognitive function. Diabetes also
raises one's risk of cardiovascular disease, including stroke, which can make cognitive problems more
For the current study, Rosebud O. Roberts, MBChB, and colleagues at the Mayo
Clinic in Rochester, Minn., compared 329 adults aged 70 to 89 with mild
cognitive impairment to 1,640 people of the same age who did not have any type
of cognitive impairment. Each participant had a neurological exam,
neuropsychological evaluation, and lab work to measure fasting blood glucose
(blood sugar) levels. Researchers asked the participants questions about their
diabetes history, treatment, and complications. Medical records were used to
confirm their diabetes history.
Similar rates of diabetes were noted between the two groups (20.1% for the
impaired group vs. 17.7% for the unimpaired participants).
However, those with mild cognitive impairment were more likely to:
- Have developed diabetes before age 65
- Have had the disease for 10 or more years
- Require insulin treatment
- Have complications of the disease
Roberts' team says severe diabetes is more likely to be associated with
poorly controlled blood sugars, which can damage nerve cells in the brain and
lead to cognitive impairment.
Diabetes-related damage to blood vessels may also lead to cognitive problems.
People with diabetic
retinopathy, a complication of diabetes that affects small blood vessels in
the eyes, are twice as likely to have mild cognitive impairment, a finding that
supports this theory, study authors add.