Older news items (pre-2010) brought over from the old website
Diabetic episodes affect memory
A study involving 62 children with type 1 diabetes, of whom 33 had experienced diabetic ketoacidosis, has found those with such experience performed significantly worse on a memory test that tested their ability to recall events in association with specific details. The finding points to the importance of avoiding diabetic ketoacidosis, which is avoidable in those known to have diabetes.
[1384] Ghetti, S., Lee J. K., Sims C. E., DeMaster D. M., & Glaser N. S.
(2010). Diabetic Ketoacidosis and Memory Dysfunction in Children with Type 1 Diabetes.
The Journal of Pediatrics. 156(1), 109 - 114.
http://www.eurekalert.org/pub_releases/2009-10/uoc--dea101909.php
Poor glucose control linked to cognitive impairment in diabetics
The ongoing Memory in Diabetes (MIND) study, involving some 3,000 type 2 diabetics 55 years and older, has found that cognitive functioning abilities drop as average blood sugar levels rise. However, there was no connection between daily blood glucose levels and cognitive performance. The study adds to growing evidence that poorer blood glucose control is strongly associated with poorer memory function, that may eventually lead to mild cognitive impairment, vascular dementia and Alzheimer's disease. It is also possible that people with impaired cognitive ability are less compliant in taking medications and controlling their diabetes. Further research will test the hypothesis that improving glucose control results in improved cognitive function.
[797] Marcovina, S. M., Launer L. J., Cukierman-Yaffe T., Gerstein H. C., Williamson J. D., Lazar R. M., et al.
(2009). Relationship Between Baseline Glycemic Control and Cognitive Function in Individuals With Type 2 Diabetes and Other Cardiovascular Risk Factors.
Diabetes Care. 32(2), 221 - 226.
http://www.eurekalert.org/pub_releases/2009-02/wfub-hbs021109.php
Adult-onset diabetes slows mental functioning in several ways, with deficits appearing early
A comparison of 41 adults with diabetes and 424 adults in good health, aged between 53 and 90, has revealed that healthy adults performed significantly better than adults with diabetes on two of the five domains tested: executive functioning and speed of processing. There were no significant differences on tests of episodic and semantic memory, verbal fluency, reaction time and perceptual speed. The effect remained even when only the younger group (those below 70) were analyzed, indicating that the diabetes-linked cognitive deficits appear early and remain stable.
[796] Yeung, S. E., Fischer A. L., & Dixon R. A.
(2009). Exploring effects of type 2 diabetes on cognitive functioning in older adults.
Neuropsychology. 23(1), 1 - 9.
http://www.eurekalert.org/pub_releases/2009-01/apa-ads123008.php
Blood sugar linked to normal cognitive aging
Following research showing that decreasing brain function in the area of the hippocampus called the dentate gyrus is a main contributor of normal age-related cognitive decline, an imaging study has been investigating the cause of this decreasing function by looking at measures that typically change during aging, like rising blood sugar, body mass index, cholesterol and insulin levels. The study of 240 community-based nondemented elders (average age 80 years), of whom 60 had type 2 diabetes, found that decreasing activity in the dentate gyrus only correlated with levels of blood glucose. The same association was also found in aging rhesus monkeys and in mice. The finding suggests that maintaining blood sugar levels, even in the absence of diabetes, could help maintain aspects of cognitive health. It also suggests that one reason why physical exercise benefits memory may be its effect on lowering glucose levels.
[830] Mayeux, R., Vannucci S. J., Small S. A., Wu W., Brickman A. M., Luchsinger J., et al.
(2008). The brain in the age of old: The hippocampal formation is targeted differentially by diseases of late life.
Annals of Neurology. 64(6), 698 - 706.
http://www.eurekalert.org/pub_releases/2008-12/cumc-rac121508.php
Diabetic seniors may experience memory declines after eating high-fat food
Growing evidence links diabetes to cognitive impairment. Now a small study of 16 adults (aged 50 years and older) with type 2 diabetes compared their cognitive performance on three separate occasions, fifteen minutes after consuming different meals. One meal consisted of high fat products – a danish pastry, cheddar cheese and yogurt with added whipped cream; the second meal was only water; and the third was the high-fat meal plus high doses of vitamins C (1000 mg) and E (800 IU) tablets. Researchers found that vitamin supplementation consistently improved recall scores relative to the meal alone, while those who ate the high fat meal without vitamin supplements showed significantly more forgetfulness of words and paragraph information in immediate and time delay recall tests. Those on water meal and meal with vitamins showed similar levels in cognitive performance. The finding indicates not only that diabetics can temporarily further worsen already underlying memory problems associated with the disease by consuming unhealthy meals, but also that this can be remedied by taking high doses of antioxidant vitamins C and E with the meal, suggesting that the effect of high-fat foods is to cause oxidative stress. However, this is hardly a recommended course of action, and the real importance of this finding is that it emphasizes the need for diabetics to consume healthy foods high in antioxidants, like fruits and vegetables. Of course, this is a very small study, and further replication is needed.
[1094] Chui, M., & Greenwood C.
(2008). Antioxidant vitamins reduce acute meal-induced memory deficits in adults with type 2 diabetes.
Nutrition Research. 28(7), 423 - 429.
http://www.eurekalert.org/pub_releases/2008-06/bcfg-swt062408.php
Stress hormone impacts memory, learning in diabetic rodents
A rodent study sheds light on why diabetes can impair cognitive function. The study found that increased levels of a stress hormone (called cortisol in humans) in diabetic rats impaired synaptic plasticity and reduced neurogenesis in the hippocampus. When levels returned to normal, the hippocampus recovered. Cortisol production is controlled by the hypothalamic-pituitary axis (HPA). People with poorly controlled diabetes often have an overactive HPA axis and excessive cortisol.
[1050] Stranahan, A. M., Arumugam T. V., Cutler R. G., Lee K., Egan J. M., & Mattson M. P.
(2008). Diabetes impairs hippocampal function through glucocorticoid-mediated effects on new and mature neurons.
Nature Neuroscience. 11(3), 309 - 317.
http://www.eurekalert.org/pub_releases/2008-02/nioa-shi021508.php
Tight diabetes control does not impact cognitive ability in type 1 diabetes
A long-running study involving 1,441 type 1 diabetics, aged 13 to 39, has demonstrated that multiple episodes of severe hypoglycaemia, though they can cause confusion, irrational behavior, convulsions and unconsciousness, do not lead to long-term loss of cognitive ability.
[1120] The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications(DCCT/EDIC) Study Research
(2007). Long-Term Effect of Diabetes and Its Treatment on Cognitive Function.
N Engl J Med. 356(18), 1842 - 1852.
http://www.eurekalert.org/pub_releases/2007-05/jdc-sst050107.php
Brain function not impaired by tight diabetes control and hypoglycemia
Previous research had indicated that tight blood glucose control -- achieved by taking three or more insulin injections daily – meant type 1 diabetics were three times as likely to suffer episodes of severe hypoglycemia, raising the fear that it might lead to a long-term loss of cognitive ability. Now a follow-up study provides the reassuring news that there was no link between multiple severe hypoglycemic reactions and impaired cognitive function in people with type 1 diabetes.
Jacobson, A.M. et al. 2006. Effects of Intensive and Conventional Treatment on Cognitive Function Twelve Years after the Completion of the Diabetes Control and Complications Trial (DCCT). Abstract Number 750232, presented at the American Diabetes Association's 66th Annual Scientific Sessions held in Washington, D.C, June 9—13.
http://www.eurekalert.org/pub_releases/2006-06/jdc-lss060806.php
Fat hormone linked to learning and memory
A new study reveals why obese patients who have diabetes also may have problems with their long-term memory. Leptin — the so-called ‘fat’ hormone — doesn't cross into the brain to help regulate appetite in obese people. Leptin also acts in the hippocampus, suggesting that leptin plays a role in learning and memory. The new study supports this by demonstrating that mice navigated a maze better after they received leptin. Moreover, mice with elevated levels of amyloid-beta plaques (characteristic of Alzheimer's) were particularly sensitive to leptin.
[2400] Farr, S. A., Banks W. A., & Morley J. E.
(2006). Effects of leptin on memory processing.
Peptides. 27(6), 1420 - 1425.
http://www.sciencedaily.com/releases/2006/06/060614090511.htm
http://www.eurekalert.org/pub_releases/2006-06/slu-alb061306.php
Age-related vision problems may be associated with cognitive impairment
Age-related macular degeneration (AMD) develops when the macula, the portion of the eye that allows people to see in detail, deteriorates. An investigation into the relationship between vision problems and cognitive impairment in 2,946 patients has been carried out by The Age-Related Eye Disease Study (AREDS) Research Group. Tests were carried out every year for four years. Those who had more severe AMD had poorer average scores on cognitive tests, an association that remained even after researchers considered other factors, including age, sex, race, education, smoking, diabetes, use of cholesterol-lowering medications and high blood pressure. Average scores also decreased as vision decreased. It’s possible that there is a biological reason for the association; it is also possible that visual impairment reduces a person’s capacity to develop and maintain relationships and to participate in stimulating activities.
Chaves, P.H.M. et al. 2006. Association Between Mild Age-Related Eye Disease Study Research Group. 2006. Cognitive Impairment in the Age-Related Eye Disease Study: AREDS Report No. 16. Archives of Ophthalmology,124, 537-543.
http://www.eurekalert.org/pub_releases/2006-04/jaaj-avp040606.php
Review supports link between lifestyle factors and cognitive function in older adults
A review of 96 papers involving 36 very large, ongoing epidemiological studies in North America and Europe looking at factors involved in maintaining cognitive and emotional health in adults as they age has concluded that controlling cardiovascular risk factors, such as reducing blood pressure, reducing weight, reducing cholesterol, treating (or preferably avoiding) diabetes, and not smoking, is important for maintaining brain health as we age. The link between hypertension and cognitive decline was the most robust across studies. They also found a consistent close correlation between physical activity and brain health. However, they caution that more research is needed before specific recommendations can be made about which types of exercise and how much exercise are beneficial. They also found protective factors most consistently reported for cognitive health included higher education level, higher socio-economic status, emotional support, better initial performance on cognitive tests, better lung capacity, more physical exercise, moderate alcohol use, and use of vitamin supplements. Psychosocial factors, such as social disengagement and depressed mood, are associated with both poorer cognitive and emotional health in late life. Increased mental activity throughout life, such as learning new things, may also benefit brain health.
Wagster M, Hendrie H, Albert M, Butters M, Gao S, Knopman DS, Launer L, Yaffe K, Cuthbert B, Edwards E. The NIH Cognitive and Emotional Health ProjectReport of the Critical Evaluation Study Committee. Alzheimer's and Dementia [Internet]. 2006 ;2(1):12 - 32. Available from: http://www.alzheimersanddementia.com/article/S1552-5260(05)00503-0/abstract?articleId=&articleTitle=&citedBy=false&medlinePmidWithoutMDLNPrefix=&overridingDateRestriction=&related=false&restrictdesc_author=&restrictDescription=&restrictName.jalz=jalz&rest
http://www.eurekalert.org/pub_releases/2006-02/aa-nss021606.php
Risk for lowered cognitive performance greater in people at high risk for stroke
A new large-scale study supports earlier suggestions that those with a high risk for stroke within 10 years are also at risk for lowered cognitive function and show a pattern of deficits similar to that seen in mild vascular cognitive impairment. It is speculated that the reason may lie in structural and functional changes in the brain that do not rise to the level of clinical detection, and this is supported by a recent brain imaging study showing that abnormal brain atrophy is related both to higher risk of stroke and poorer cognitive ability. The probability of experiencing stroke within 10 years was calculated using weighted combinations of age, systolic blood-pressure, presence of diabetes, cigarette smoking, history of cardiovascular disease, treatment for hypertension and atrial fibrillation.
[1422] Elias, M. F., Sullivan L. M., D'Agostino R. B., Elias P. K., Beiser A., Au R., et al.
(2004). Framingham stroke risk profile and lowered cognitive performance.
Stroke; a Journal of Cerebral Circulation. 35(2), 404 - 409.
http://www.eurekalert.org/pub_releases/2004-01/ama-rfl010804.php
Age-related changes in the brain's white matter affect cognitive function
From around age 60, "white-matter lesions" appear in the brain, significantly affecting cognitive function. But without cognitive data from childhood, it is hard to know how much of the difference in cognitive abilities between elderly individuals is due to aging. A longitudinal study has been made possible by the Scottish Mental Survey of 1932, which gave 11-year-olds a validated cognitive test. Scottish researchers have tracked down healthy living men and women who took part in this Survey and retested 83 participants. Testing took place in 1999, when most participants were 78 years old.
It was found that the amount of white-matter lesions made a significant contribution to general cognitive ability differences in old age, independent of prior ability. The amount of white-matter lesions contributed 14.4% of the variance in cognitive scores; early IQ scores contributed 13.7%. The two factors were independent.
Although white-matter lesions are viewed as a normal part of aging, they are linked with other health problems, in particular to circulatory problems (including hypertension, diabetes, heart disease and cardiovascular risk factors).
[442] Deary, I. J., Leaper S. A., Murray A. D., Staff R. T., & Whalley L. J.
(2003). Cerebral white matter abnormalities and lifetime cognitive change: a 67-year follow-up of the Scottish Mental Survey of 1932.
Psychology and Aging. 18(1), 140 - 148.
http://www.eurekalert.org/pub_releases/2003-03/apa-aci031703.php
High sugar blood levels linked to poor memory
A new study takes an important step in explaining cognitive impairment in diabetics, and suggests a possible cause for some age-related memory impairment. The study assessed non-diabetic middle-aged and elderly people. Those with impaired glucose tolerance (a pre-diabetic condition) had a smaller hippocampus and scored worse on tests for recent memory. These results were independent of age or overall cognitive performance. The brain uses glucose almost exclusively as a fuel source. The ability to get glucose from the blood is reduced in diabetes. The study raises the possibility that exercise and weight loss, which help control blood sugar levels, may be able to reverse some of the memory loss that accompanies aging.
[543] Convit, A., Wolf O. T., Tarshish C., & de Leon M. J.
(2003). Reduced glucose tolerance is associated with poor memory performance and hippocampal atrophy among normal elderly.
Proceedings of the National Academy of Sciences of the United States of America. 100(4), 2019 - 2022.
http://www.eurekalert.org/pub_releases/2003-02/nyum-hsb013003.php
Diabetes and high blood pressure linked to decline in mental ability
A large-scale six-year study of people aged 40 to 70 years old found that people with diabetes and high blood pressure are more likely to experience cognitive decline. Diabetes was associated with greater cognitive decline for those younger than 58 as well as those older than 58, but high blood pressure was a risk factor only for the 58 and older group.
[2534] Knopman, D. S., Boland L. L., Mosley T., Howard G., Liao D., Szklo M., et al.
(2001). Cardiovascular risk factors and cognitive decline in middle-aged adults.
Neurology. 56(1), 42 - 48.
http://www.eurekalert.org/pub_releases/2001-01/MC-Nsld-0701101.php
http://www.eurekalert.org/pub_releases/2001-01/AAoN-Dahb-0801101.php