Research not directly memory-related, but factor affects cognition
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.
Those with diabetes also had cortical tissue that was an average of 0.03 millimeter less than those who didn't have diabetes, regardless of their cognitive status. This greater brain atrophy in the frontal and parietal cortices may be partly related to the increase in tau protein.
There was no link between diabetes and amyloid-beta, the other main pathological characteristic of Alzheimer's.
Previous research has indicated that people with type 2 diabetes have double the risk of developing dementia. Previous research has also found that those who had been diabetic for longer had a greater degree of brain atrophy
The findings support the idea that type 2 diabetes may have a negative effect on cognition independent of dementia, and that this effect may be driven by an increase in tau phosphorylation.
 Moran, C., Beare R., Phan T. G., Bruce D. G., Callisaya M. L., Srikanth V., et al.
(2015). Type 2 diabetes mellitus and biomarkers of neurodegeneration.
Blood pressure data from 378 participants in the Framingham Heart Study has revealed that those who had high systolic blood pressure when they were 50-60 years old scored worse on a working memory test 30 years later. However, an association with verbal fluency was only significant for those with the 'Alzheimer's' APOe4 gene.
The finding adds to increasing evidence that managing health conditions such as cardiovascular health, diabetes, and hypertension, in midlife is important for cognitive health in old age, but tempers the message by suggesting that effects may be quite specific, with some applying mainly to those who are genetically vulnerable.
Nishtala A, Himali JJ, Beiser A, Murabito JM, Seshadri S, Wolf PA, Au R (2015) Midlife Hypertension Risk and Cognition in the Non-Demented Oldest Old: Framingham Heart Study. J Alzheimers Dis 47, 197-204.
A twin study challenges findings that receiving anesthesia at a very young age (below four) is associated with subsequent learning problems. The Dutch study involved 1,143 pairs of identical twins, and compared groups where both twins had been exposed to anesthesia before age 3, where neither had been exposed to anesthesia, or where only one member of the pair had been exposed to anesthesia. Cognitive performance at age 12 was assessed from a standardized national exam administered to all children in the Netherlands at that age. It was found that there was no difference in cognitive performance between twins where one had been exposed to anesthesia and the other had not. It therefore seems likely that the association is due to children likely to undergo surgery early in life having significant medical problems that are associated with a vulnerability to learning disabilities.
 Bartels, M., Althoff R. R., & Boomsma D. I.
(2009). Anesthesia and cognitive performance in children: no evidence for a causal relationship.
Twin Research and Human Genetics: The Official Journal of the International Society for Twin Studies. 12(3), 246 - 253.
A new study has found that drugs commonly used to anesthetize children can cause brain damage and long-term learning and memory disturbances in infant rats. The rats appeared to behave normally in most other ways, and there were no outward signs of brain damage.
 Jevtovic-Todorovic, V., Hartman R. E., Izumi Y., Benshoff N. D., Dikranian K., Zorumski C. F., et al.
(2003). Early Exposure to Common Anesthetic Agents Causes Widespread Neurodegeneration in the Developing Rat Brain and Persistent Learning Deficits.
J. Neurosci.. 23(3), 876 - 882.
Brain scans have revealed that those who regularly practiced yoga had larger brain volume in the
A study involving 74 older adults (70+), of whom 3 had mild dementia, 33 were cognitively normal and 38 had mild cognitive impairment, has found that high levels of "good" cholesterol and low levels of "bad" cholesterol correlated with lower levels of the amyloid-beta plaques in the brain (a hallmark of Alzheimer's disease).
A mouse study has found that obese mice had high levels of interleukin 1 in both their blood and their brains, and this was associated with:
Moreover, when fat was removed from the obese mice, interleukin levels dropped dramatically, and cognitive performance improved.
Previous research has indicated that about a quarter of older adults who become mildly depressed will go on to become seriously depressed within a year or two. A study comparing problem-solving therapy for primary care — a seven-step approach delivered by non-mental-health professionals to help patients resolve difficulties and thus improve coping skills and confidence — with a program of dietary coaching (same number of sessions and hours), has found that elderly adults with mild symptoms of depression responded equally well to both treatments.
A study involving 614 patients with type 2 diabetes (mean age 62) has found that longer duration of diabetes was associated with more brain volume loss, particularly in the gray matter. Roughly, for every 10 years of diabetes, the brain was similar to that of a non-diabetic person who was two years older.
However, the study did not confirm any association of diabetes characteristics with small vessel ischemic disease.
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