Mild Cognitive Impairment May Be Diabetic Companion
By John Gever
ROCHESTER, 12 aug 2008-- Mild cognitive impairment and diabetes appear to go hand-in-hand into old age, researchers here said. In a case-control study of 1,969 patients at least 70 years old, mild cognitive impairment was significantly more common in those with diabetes onset before age 75, diabetes duration of at least 10 years, treatment with insulin, and the presence of diabetic complications, reported Rosebud O. Roberts, M.B.Ch.B., of the Mayo Clinic, and colleagues, in the August issue of Archives of Neurology. The findings may signify that mild cognitive impairment is another microvascular complication of long-standing diabetes, similar to diabetic retinopathy, the researchers said.
But because the study only evaluated participants at a single time point, the researchers could not confirm that diabetes preceded the cognitive impairment and was a causative factor.
In an interview, Dr. Roberts said another study was under way in which participants are being tracked over time. The investigators hope to gather at least six years of follow-up data, which should help settle the question, she said.
The current study involved face-to-face interviews with the study participants, who were ages 70 to 89, identifying 329 persons with mild cognitive impairment. The remaining 1,640 showed no evidence of impairment.
The presence of diabetes was determined by a combination of participant self-report, fasting blood glucose levels as measured by the researchers, and medical records.
Overall, the prevalence of diabetes was similar among those with and without cognitive impairment (20.1% versus 17.7%, respectively).
But participants with long-duration or more severe diabetes were significantly more likely to show mental impairment:
Diabetes onset before age 65: OR 2.20 (95% CI 1.29 to 3.73)
Diabetes duration at least 10 years: OR 1.76 (95% CI 1.16 to 2.68)
Insulin treatment: OR 2.01 (95% CI 1.22 to 3.31)
Diabetic complications: OR 1.80 (95% CI 1.13 to 2.89)
These odds ratios were adjusted for age, sex, and educational attainment and defined diabetes by self-report with confirmation from medical records.
Dr. Roberts and colleagues found the odds ratios remained largely unchanged when the adjustments included cardiovascular risk factors, smoking status, and body mass index.
They also remained significant when the definition of diabetes was expanded to include abnormal fasting blood glucose.
Diabetes appeared to be less strongly predictive of cognitive impairment involving memory loss than with non-amnestic impairment.
"Non-amnestic [impairment] may be a prodromal stage for vascular dementia or other non-degenerative dementias, whereas amnestic [impairment] may be a prodromal stage for neurodegenerative dementias such as Alzheimer disease," Dr. Roberts and colleagues suggested. They added, however, that earlier studies have had mixed results on these associations.
Although the study does not prove that diabetes actually causes the cognitive deficits, the findings tend to support the importance of maintaining good glucose control.
She said it was one more reason for diabetics and their physicians to work on reducing obesity, exercising, and eating a healthy diet.
All participants in the trial were from the Rochester, Minn., area, meaning the results may not be generalizable to other locations or populations. The researchers also noted that eligible individuals who declined to participate in the personal interviews tended to be older men, those with lower education, and diabetic according to self-report or medical records.
"This underrepresentation of subjects with diabetes may have precluded our ability to detect a significant association between diabetes overall and mild cognitive impairment," the researchers said.
The study was funded by the National Institutes of Health and by the Robert H. and Clarice Smith and Abigail Van Buren Alzheimer's Disease Research Program. No potential conflicts of interest were reported.
Primary source: Archives of NeurologySource reference:Roberts R, et al "Association of duration and severity of diabetes mellitus with mild cognitive impairment" Arch Neurol 2008; 65: 1066-73.
By John Gever
ROCHESTER, 12 aug 2008-- Mild cognitive impairment and diabetes appear to go hand-in-hand into old age, researchers here said. In a case-control study of 1,969 patients at least 70 years old, mild cognitive impairment was significantly more common in those with diabetes onset before age 75, diabetes duration of at least 10 years, treatment with insulin, and the presence of diabetic complications, reported Rosebud O. Roberts, M.B.Ch.B., of the Mayo Clinic, and colleagues, in the August issue of Archives of Neurology. The findings may signify that mild cognitive impairment is another microvascular complication of long-standing diabetes, similar to diabetic retinopathy, the researchers said.
But because the study only evaluated participants at a single time point, the researchers could not confirm that diabetes preceded the cognitive impairment and was a causative factor.
In an interview, Dr. Roberts said another study was under way in which participants are being tracked over time. The investigators hope to gather at least six years of follow-up data, which should help settle the question, she said.
The current study involved face-to-face interviews with the study participants, who were ages 70 to 89, identifying 329 persons with mild cognitive impairment. The remaining 1,640 showed no evidence of impairment.
The presence of diabetes was determined by a combination of participant self-report, fasting blood glucose levels as measured by the researchers, and medical records.
Overall, the prevalence of diabetes was similar among those with and without cognitive impairment (20.1% versus 17.7%, respectively).
But participants with long-duration or more severe diabetes were significantly more likely to show mental impairment:
Diabetes onset before age 65: OR 2.20 (95% CI 1.29 to 3.73)
Diabetes duration at least 10 years: OR 1.76 (95% CI 1.16 to 2.68)
Insulin treatment: OR 2.01 (95% CI 1.22 to 3.31)
Diabetic complications: OR 1.80 (95% CI 1.13 to 2.89)
These odds ratios were adjusted for age, sex, and educational attainment and defined diabetes by self-report with confirmation from medical records.
Dr. Roberts and colleagues found the odds ratios remained largely unchanged when the adjustments included cardiovascular risk factors, smoking status, and body mass index.
They also remained significant when the definition of diabetes was expanded to include abnormal fasting blood glucose.
Diabetes appeared to be less strongly predictive of cognitive impairment involving memory loss than with non-amnestic impairment.
"Non-amnestic [impairment] may be a prodromal stage for vascular dementia or other non-degenerative dementias, whereas amnestic [impairment] may be a prodromal stage for neurodegenerative dementias such as Alzheimer disease," Dr. Roberts and colleagues suggested. They added, however, that earlier studies have had mixed results on these associations.
Although the study does not prove that diabetes actually causes the cognitive deficits, the findings tend to support the importance of maintaining good glucose control.
She said it was one more reason for diabetics and their physicians to work on reducing obesity, exercising, and eating a healthy diet.
All participants in the trial were from the Rochester, Minn., area, meaning the results may not be generalizable to other locations or populations. The researchers also noted that eligible individuals who declined to participate in the personal interviews tended to be older men, those with lower education, and diabetic according to self-report or medical records.
"This underrepresentation of subjects with diabetes may have precluded our ability to detect a significant association between diabetes overall and mild cognitive impairment," the researchers said.
The study was funded by the National Institutes of Health and by the Robert H. and Clarice Smith and Abigail Van Buren Alzheimer's Disease Research Program. No potential conflicts of interest were reported.
Primary source: Archives of NeurologySource reference:Roberts R, et al "Association of duration and severity of diabetes mellitus with mild cognitive impairment" Arch Neurol 2008; 65: 1066-73.
No comments:
Post a Comment