alzheimers diabetes

Diabetes and tau tangles linked independently of Alzheimer's

A study involving older adults has found that diabetes was associated with higher levels of tau protein and greater brain atrophy.

The study involved 816 older adults (average age 74), of whom 397 had mild cognitive impairment, 191 had Alzheimer's disease, and 228 people had no cognitive problems. Fifteen percent (124) had diabetes.

Those with diabetes had greater levels of tau protein in the spinal and brain fluid regardless of cognitive status. Tau tangles are characteristic of Alzheimer's.

Rate of dementia has decreased for African-Americans

A long-running study comparing African-Americans and Nigerians has found the incidence of dementia has fallen significantly over two decades among the African-Americans, but remained the same for the Nigerians (for whom it was lower anyway).

The study enrolled two cohorts, one in 1992 and one in 2001, who were evaluated every 2–3 years until 2009. The 1992 cohort included 1440 older African-Americans (70+) and 1774 Nigerian Yoruba; the 2001 cohort included 1835 African-Americans and 1895 Yoruba. None of the participants had dementia at study beginning.

Risk factors that affect progression from MCI to dementia

A large meta-analysis has concluded that having diabetes increases the chance that a person with mild cognitive impairment will progress to dementia by 65%.

There was no consistent evidence that hypertension or cholesterol levels increased the risk of someone with MCI progressing to dementia. Smoking was similarly not associated with increased risk, although the reason for this probably lies in mortality: smokers tend to die before developing dementia.

Alzheimer's & Diabetes

See also

Diabetes

Sugar

Older news items (pre-2010) brought over from the old website

Does diabetes speed up memory loss in Alzheimer's disease?

A four-year study involving 608 people with mild to moderate Alzheimer's disease, of whom just over 10% (63) had diabetes, has unexpectedly found that memory loss in those without diabetes declined faster than those with diabetes. The researchers speculate that elderly people with diabetes may be more likely to be taking cardiovascular medications (although having vascular factors was controlled for), or there may be some differences in the brain pathology of Alzheimer’s with diabetes compared to Alzheimer’s without diabetes.

Sanz, C., Andrieu, S., Sinclair, A., Hanaire, H., Vellas, B., & For the REAL.FR Study Group. (2009). Diabetes is associated with a slower rate of cognitive decline in Alzheimer disease. Neurology, 73(17), 1359-1366. doi: 10.1212/WNL.0b013e3181bd80e9.

http://www.eurekalert.org/pub_releases/2009-10/aaon-dds102009.php

Diabetes, high blood pressure may cause Alzheimer's sufferers to die sooner

A study involving 323 people who had no memory problems when first tested but later developed dementia has found that, after an Alzheimer’s diagnosis, people with diabetes were twice as likely to die sooner than those without diabetes, while those with high blood pressure were two-and-a-half times more like to die sooner than those with normal blood pressure. The average lifespan of a person diagnosed with Alzheimer's is three to nine years.

Helzner, E.P. et al. 2008. Survival in Alzheimer disease: A multiethnic, population-based study of incident cases. Neurology, 71, 1489-1495.

http://www.eurekalert.org/pub_releases/2008-11/aaon-dhb102908.php

Diabetes in mid-life linked to increased risk of Alzheimer's disease

A large Swedish study involved over 2000 men has found that those with low insulin secretion capacity at age 50 were nearly one-and-a-half times more likely to develop Alzheimer’s disease than people without insulin problems. The risk remained significant regardless of blood pressure, cholesterol, body mass index and education, and was strongest in people who did not have the APOE4 gene.

Rönnemaa, E. et al. 2008. Impaired insulin secretion increases the risk of Alzheimer disease. Neurology, first published on April 9 as doi: doi:10.1212/01.wnl.0000310646.32212.3a

http://www.eurekalert.org/pub_releases/2008-04/aaon-dim040108.php

Significant dementia risk attributable to small blood vessel damage

Autopsy data of 221 men and women found that the brains of one-third of individuals who had dementia before death showed evidence of small, cumulative blood vessel damage that can arise from hypertension or diabetes.

The findings were reported at the annual meeting of the American Society for Biochemistry and Molecular Biology, April 5-9, San Diego.

http://www.eurekalert.org/pub_releases/2008-04/asfb-sdr040208.php

Link between diabetes and Alzheimer's disease

A mouse study has shed light on the connection between diabetes and Alzheimer’s. It appears that the elevated blood glucose levels characteristic of diabetes interacts with beta amyloid in a way damaging to blood vessels in the brain.

Burdo, J.R. et al. 2008. The pathological interaction between diabetes and presymptomatic Alzheimer's disease. Neurobiology of Aging, Available online 26 March 2008

http://www.eurekalert.org/pub_releases/2008-04/si-ssl043008.php

Support for view of Alzheimer's as form of diabetes

Research in the last few years has raised the possibility that Alzheimer’s memory loss could be due to a third form of diabetes. A new study clarifies the connection between insulin and Alzheimer’s. It seems that the toxic protein ADDL, found in the brains of individuals with Alzheimer’s, removes insulin receptors from nerve cells, rendering those neurons insulin resistant. The findings suggest that some existing drugs now used to treat diabetic patients may be useful for Alzheimer’s treatment.

Zhao,W-Q. et al. 2007. Amyloid beta oligomers induce impairment of neuronal insulin receptors. FASEB Journal, published online ahead of print August 24.

http://www.eurekalert.org/pub_releases/2007-09/nu-dst092607.php

Diabetes associated with increased risk of mild cognitive impairment

A study involving 918 individuals older than 65 years (average age 75.9) who did not have mild cognitive disorder or dementia when they enrolled has found that, over some 6 years, diabetes was related to a significantly higher risk of developing amnestic mild cognitive impairment, after controlling for other risk factors. The results support other findings that type 2 diabetes mellitus increases the risk of Alzheimer's.

Luchsinger, J.A. et al. 2007. Relation of Diabetes to Mild Cognitive Impairment. Archives of Neurology, 64, 570-575.

http://www.eurekalert.org/pub_releases/2007-04/jaaj-dmb040507.php

High blood sugar linked to MCI and dementia

The first study to investigate the association over time between blood sugar and the risk of cognitive difficulties involved 1,983 post-menopausal women (mean age 67 years) and found that each 1% increase in their glycosylated hemoglobin level at the start of the four-year study period was associated with a 40% increased risk of developing MCI or dementia four years later. The glycosylated hemoglobin test gives a more stable measure of blood sugar level than the standard test, which measures blood sugar it the time of testing. A result of 7% or less indicates good long-term blood sugar control. Those with a level of 7% or more were four times more likely to develop MCI or dementia than women who tested at less than 7%.

Yaffe, K. et al. 2006. Glycosylated Hemoglobin Level and Development of Mild Cognitive Impairment or Dementia in Older Women. Journal of Nutrition, Health, and Aging, 10 (4)

http://www.eurekalert.org/pub_releases/2006-08/uoc--chb080906.php

Reduced insulin in the brain triggers Alzheimer's degeneration

By depleting insulin and its related proteins in the brain, researchers have replicated the progression of Alzheimer's disease – including plaque deposits, neurofibrillary tangles, impaired cognitive functioning, cell loss and overall brain deterioration – in an experimental animal model. Brain deterioration was not related to the pancreas, raising the possibility that Alzheimer's is a neuroendocrine disorder, or a Type 3 diabetes.

Lester-Coll, N. et al. 2006. Intracerebral streptozotocin model of type 3 diabetes: relevance to sporadic Alzheimer’s disease. Journal of Alzheimer’s Disease, 9(1)

http://www.eurekalert.org/pub_releases/2006-03/l-rii031606.php

Link between insulin and Alzheimer's

A new study has found that insulin and its related proteins are produced in the brain as well as the pancreas, and that reduced levels of these contribute to the degeneration of brain cells, an early symptom of Alzheimer's disease. The finding raises the possibility of a Type 3 diabetes.

de la Monte, S.M. & Wands, J.R. 2005. Review of insulin and insulin-like growth factor expression, signaling, and malfunction in the central nervous system: Relevance to Alzheimer's disease Journal of Alzheimer's Disease, 7(1), 45-61.

http://www.eurekalert.org/pub_releases/2005-03/l-rdl030205.php

Diabetics at significantly higher risk for Alzheimer's disease

New findings from the Religious Orders Study add to research suggesting a link between diabetes mellitus and an increased risk of developing Alzheimer's disease. Some aspects of cognitive function appear to be affected differently than others, in particular perceptual speed declined significantly faster in those with diabetes.

Arvanitakis, Z., Wilson, R. S., Bienias, J. L., Evans, D. A., & Bennett, D. A. (2004). Diabetes Mellitus and Risk of Alzheimer Disease and Decline in Cognitive Function. Arch Neurol, 61(5), 661-666. Retrieved from http://archneur.ama-assn.org/cgi/content/abstract/61/5/661

http://www.eurekalert.org/pub_releases/2004-05/rpsl-das051204.php

Insulin-degrading enzyme may affect risk of Alzheimer’s disease

A new mouse study suggests that low levels of insulysin, an enzyme that degrades insulin, could increase the risk for Alzheimer's, and points to a new mechanism linking diseases like diabetes and Alzheimer's — the competition of multiple substrates, such as insulin and amyloid-beta, for a limiting amount of the insulysin enzyme. The insulysin enzyme, it seems, also degrades amyloid-beta peptides, and even a partial decrease in insulysin activity was found to raise amyloid-beta peptide levels in the brain.

Miller, B. C., Eckman, E. A., Sambamurti, K., Dobbs, N., Chow, M., Eckman, C. B., … Thiele, D. L. (2003). Amyloid-β peptide levels in brain are inversely correlated with insulysin activity levels in vivo. Proceedings of the National Academy of Sciences, 100(10), 6221-6226. Retrieved from http://www.pnas.org/content/100/10/6221.abstract

http://www.eurekalert.org/pub_releases/2003-05/uots-iem050603.php

Poorly controlled diabetes could lead to dementia in the elderly

It now appears that the reason why diabetic people age 60 and older tend to perform more poorly on cognitive tests is because of improper management of their disease. A recent study evaluated the association between diabetes mellitus status and cognitive function in 2,583 adults aged 60 and older, grouping participants according to their diabetic status (poorly controlled diabetes; adequately controlled diabetes; those with impaired glucose tolerance; and a non-diabetic control group). Cognitive ability was measured by a series of simple memory questions. Only those with poorly controlled diabetes performed poorly on the cognitive test.

The researchers presented their findings in April at the American Academy of Neurology conference in Honolulu.

http://www.eurekalert.org/pub_releases/2003-05/osu-pcd050503.php

High blood sugar may raise Alzheimer’s risk

Submitted by Fiona McPherson on Sat, 11 May 2013 - 20:03

I’ve talked before about the evidence linking diabetes to an increased risk of Alzheimer’s disease, but now a new study suggests that elevated blood sugar levels increase Alzheimer’s risk even in those without diabetes, even in those without ‘pre-diabetes’.

Treating high blood pressure, cholesterol, diabetes may lower risk of Alzheimer's disease

A study following 837 people with MCI, of whom 414 (49.5%) had at least one vascular risk factor, has found that those with risk factors such as high blood pressure, diabetes, cerebrovascular disease and high cholesterol were twice as likely to develop Alzheimer's disease. Over five years, 52% of those with risk factors developed Alzheimer's, compared to 36% of those with no risk factors In total, 298 people (35.6%) developed Alzheimer's.

Link among Alzheimer's disease, Down syndrome, atherosclerosis and diabetes

It’s been suggested before that Down syndrome and Alzheimer's are connected. Similarly, there has been evidence for connections between diabetes and Alzheimer’s, and cardiovascular disease and Alzheimer’s. Now new evidence shows that all of these share a common disease mechanism. According to animal and cell-culture studies, it seems all Alzheimer's disease patients harbor some cells with three copies of chromosome 21, known as trisomy 21, instead of the usual two. Trisomy 21 is characteristic of all the cells in people with Down syndrome.

Major depression more than doubles risk of dementia among adults with diabetes

Both diabetes and clinical depression are known to be risk factors for dementia. Now a study that tracked nearly 4000 diabetics over 5 years has found having both increased the risk 2.7-fold. Nearly 8% of the diabetics with major depression (36 of 455) developed dementia over the five years, compared to 4.8% of those with diabetes alone (163 of 3382). Those who developed dementia within 2 years of being diagnosed with depression were excluded. Depression is common among people who have diabetes.

Subscribe to alzheimers diabetes