risk factors

High cholesterol intake & eggs don't increase dementia risk

A large, long-running Finnish study looking at the dietary habits of 2,497 men aged 42-60 has found that a high intake of dietary cholesterol was not associated with the risk of dementia or Alzheimer's disease, even among carriers of the ‘Alzheimer’s gene’ APOE4.

Previous research has found that the effect of dietary cholesterol on serum cholesterol levels is more visible in carriers of APOE4. In Finland, the prevalence of the APOE4 gene variant is exceptionally high and approximately a third of the population are carriers.

The consumption of eggs was not only not associated with an increased risk of dementia or Alzheimer's, but on the contrary, was associated with better cognitive performance on some tests.

The highest level of average daily dietary cholesterol intake was 520 mg and these participants consumed an average of one egg per day.

Reference: 

Ylilauri, M.P.T. et al. 2017. Association of dietary cholesterol and egg intakes with risk of incident dementia or Alzheimer's disease: The Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Clinical Nutrition; First published online January 4, 2017. doi: 10.3945/ajcn.116.146753 http://ajcn.nutrition.org/content/early/2017/01/04/ajcn.116.146753.abstract?papetoc

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

Is soda bad for your brain, especially diet soda?

Data from the large and very long-running Framingham Heart Study has revealed that people who drink sugary drinks frequently are more likely to have poorer memory, smaller overall brain volume, and a significantly smaller hippocampus. Moreover, a second study found that those who drank diet soda daily were almost three times as likely to develop stroke and dementia over a 10-year period, compared to those who didn’t – suggesting that substituting artificial sweeteners for the sugar doesn’t make matters better.

Age, smoking, diet quality, and other factors were taken into account, but the analysis couldn’t completely control for preexisting conditions like diabetes. Diabetics tend to drink more diet soda on average, as a way to limit their sugar consumption, and some of the correlation between diet soda intake and dementia may be due to diabetes, a known risk factor for dementia.

Reference: 

Pase, M. P., Himali, J. J., Jacques, P. F., DeCarli, C., Satizabal, C. L., Aparicio, H., Vasan, R. S., Beiser, A. S., & Seshadri, S. (2017). Sugary beverage intake and preclinical Alzheimer’s disease in the community. Alzheimer’s & Dementia, 13(9), 955–964. https://doi.org/10.1016/j.jalz.2017.01.024

Pase Matthew P., Himali Jayandra J., Beiser Alexa S., Aparicio Hugo J., Satizabal Claudia L., Vasan Ramachandran S., Seshadri Sudha, & Jacques Paul F. (2017). Sugar- and Artificially Sweetened Beverages and the Risks of Incident Stroke and Dementia. Stroke, 48(5), 1139–1146. https://doi.org/10.1161/STROKEAHA.116.016027

Source: 

Topics: 

tags lifestyle: 

tags problems: 

If you flush when you drink alcohol, drinking may increase your risk of Alzheimer’s

Research using human cell cultures and mice suggests that those with an uncommon variation of the aldehyde dehydrogenase 2 gene (ALDH2) may be more at risk of Alzheimer's if they consume alcohol. This gene variation is associated with facial redness following alcohol consumption, reflecting reduced activity of an enzyme that protects against a toxin produced by alcohol consumption (acetaldehyde). Flushing, and inflammation, is a response to the toxin.

The gene variant occurs in about 8% of the world’s population, but is particularly prevalent among people from East Asia, where nearly half the population carries it.

The research builds on previous epidemiological studies in East Asian populations that have previously suggested an association between the mutation in ALDH2 that causes facial flushing and Alzheimer’s disease. However, there have also been other studies that didn’t find an association.

Confirmation of these results requires large epidemiological studies of humans to see whether alcohol drinkers who have the mutation develop Alzheimer’s disease at a higher-than-average rate.

The gene variant is also associated with a higher risk of developing cancer in the esophagus.

Reference: 

Joshi, A.U., Van Wassenhove, L.D., Logas, K.R. et al. Aldehyde dehydrogenase 2 activity and aldehydic load contribute to neuroinflammation and Alzheimer’s disease related pathology. acta neuropathol commun 7, 190 (2019). https://doi.org/10.1186/s40478-019-0839-7

Source: 

Topics: 

tags lifestyle: 

tags memworks: 

tags problems: 

Healthy lifestyle associated with lower dementia risk regardless of genes

  • A very large study found that an unhealthy lifestyle and high genetic risk were independently associated with higher dementia risk, and a healthy lifestyle reduced the risk for those at high genetic risk.

Data from 196,383 older adults (60+; mean age 64) in the UK Biobank found that a healthy lifestyle was associated with lower dementia risk regardless of genes.

Both an unhealthy lifestyle and high genetic risk were associated with higher dementia risk.

Lifestyle factors included smoking, physical activity, diet, and alcohol consumption. Bearing in mind that lifestyle factors were self-reported, 68.1% followed a healthy lifestyle, 23.6% were intermediate, and 8.2% followed an unhealthy lifestyle. Regarding genes, 20% were at high risk, 60% were intermediate, and 20% were at low risk.

Of those at high genetic risk, 1.23% developed dementia in the 8-year period (remember that these are people who are still relatively — the average age at study end would still only be 72), compared with 0.63% of those at low genetic risk. Of those at high genetic risk plus an unhealthy lifestyle, 1.78% developed dementia compared to 0.56% of those at low risk with a healthy lifestyle. Among those who had a high genetic risk but a healthy lifestyle, 1.13% developed dementia in the period.

I trust that these people will continue to be followed — it will be very interesting to see the statistics in another 10 years.

There were 1,769 new cases of dementia during the 8-year study period.

https://www.eurekalert.org/pub_releases/2019-07/jn-ihl071219.php

https://www.theguardian.com/society/2019/jul/14/healthy-lifestyle-may-cut-risk-of-dementia-regardless-of-genes

Reference: 

Source: 

Topics: 

tags lifestyle: 

tags problems: 

Alcohol & dementia risk

  • A rat brain cell study provides evidence that alcohol may increase Alzheimer's risk by impeding the removal of amyloid-beta protein.
  • A very large French study found that 38% of early-onset dementia cases were directly alcohol-related and 18% had an additional diagnosis of alcohol use disorders.

How alcohol increases Alzheimer's risk

A cell-culture study using rodent microglia found that some of the genes affected by alcohol and inflammation are also implicated in processes that clear amyloid beta, suggesting that alcohol may impede the clearance of amyloid beta in the brain.

In the study, rat microglial cells were exposed either to alcohol, pro-inflammatory chemicals called cytokines, or alcohol and cytokines, for 24 hours. Gene expression was altered for 312 genes under the alcohol condition; for 3,082 for the pro-inflammatory condition, and 3,552 for the alcohol and pro-inflammatory condition. Changes in gene expression ranged from a 50% decrease to a 72% increase. Many of the genes were involved in phagocytosis; just a handful of genes were involved in both phagocytosis and inflammation.

https://www.eurekalert.org/pub_releases/2018-06/uoia-hda060418.php

Chronic heavy drinking trebles dementia risk

Data from the French National Hospital Discharge database, involving over a million people diagnosed with dementia between 2008 and 2013, found that 38% of the 57,000 cases of early-onset dementia were directly alcohol-related and 18% had an additional diagnosis of alcohol use disorders.

Overall, alcohol use disorders were associated with a three times greater risk of all types of dementia.

The study only looked at people admitted to hospital due to chronic heavy drinking, so it will understate the link between alcohol use and dementia risk.

Moreover, heavy drinkers who had given up alcohol for a time did not reduce their dementia risk (although they were less likely to die early).

https://www.eurekalert.org/pub_releases/2018-02/cfaa-lso022018.php

https://www.theguardian.com/society/2018/feb/20/chronic-heavy-drinking-leads-to-serious-risk-of-dementia-study-warns

Reference: 

Source: 

Topics: 

tags lifestyle: 

tags problems: 

Diet quality in midlife not associated with dementia risk

  • A large, long-running study found that self-reported diet during midlife was not linked to later dementia risk.

A long-running study involving 8225 adults found that self-reported diet during midlife (mean age 50) was not significantly associated with subsequent risk for dementia.

Dietary intake was assessed in 1991-1993, 1997-1999, and 2002-2004, with follow-up for incident dementia until March 31, 2017. Diet quality was assessed using the Alternate Healthy Eating Index (AHEI), an 11-component diet quality score (score range, 0-110), with higher scores indicating a healthier diet.

There were 344 cases of incident dementia developed in the study period. 69.1% of participants were male.

https://www.eurekalert.org/pub_releases/2019-03/jn-wdq030719.php

Reference: 

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

Education & IQ linked to later cognitive decline & dementia

  • A large, long-running study found those with a college education maintained good cognition substantially longer than those who didn't complete high school.
  • A very large online study found that higher levels of education were strong predictors of better cognitive performance across all ages (15-60 years), but this was more true for types of cognition such as reasoning and less true for processing speed.
  • A large study of older men found that their cognitive ability at age 20 was a stronger predictor of cognitive function later in life than other factors, such as higher education, occupational complexity or engaging in late-life intellectual activities.

Americans with a college education live longer without dementia and Alzheimer's

Data from the large, long-running U.S. Health and Retirement Study found that healthy cognition characterized most of the people with at least a college education into their late 80s, while those who didn’t complete high school had good cognition up until their 70s.

The study found that those who had at least a college education lived a much shorter time with dementia than those with less than a high school education: an average of 10 months for men and 19 months for women, compared to 2.57 years (men) and 4.12 years (women).

The data suggests that those who graduated high school can expect to live (on average) at least 70% of their remaining life after 65 with good cogntion, compared to more than 80% for those with a college education, and less than 50% for those who didn't finish high school.

The analysis was based on a sample of 10,374 older adults (65+; average age 74) in 2000 and 9,995 in 2010.

https://www.eurekalert.org/pub_releases/2018-04/uosc-awa041618.php

https://academic.oup.com/psychsocgerontology/article/73/suppl_1/S20/4971564 (open access)

More education linked to better cognitive functioning later in life

Data from around 196,000 subscribers to Lumosity online brain-training games found that higher levels of education were strong predictors of better cognitive performance across the 15- to 60-year-old age range of their study participants, and appear to boost performance more in areas such as reasoning than in terms of processing speed.

Differences in performance were small for test subjects with a bachelor's degree compared to those with a high school diploma, and moderate for those with doctorates compared to those with only some high school education.

But people from lower educational backgrounds learned novel tasks nearly as well as those from higher ones.

https://www.eurekalert.org/pub_releases/2017-08/l-mel082117.php

http://www.futurity.org/higher-education-cognitive-peak-1523712/

Youthful cognitive ability strongly predicts mental capacity later in life

Data from more than 1,000 men participating in the Vietnam Era Twin Study of Aging revealed that their cognitive ability at age 20 was a stronger predictor of cognitive function later in life than other factors, such as higher education, occupational complexity or engaging in late-life intellectual activities.

All of the men, now in their mid-50s to mid-60s, took the Armed Forces Qualification Test at an average age of 20. The same test of general cognitive ability (GCA) was given in late midlife, plus assessments in seven cognitive domains.

GCA at age 20 accounted for 40% of the variance in the same measure at age 62, and approximately 10% of the variance in each of the seven cognitive domains. Lifetime education, complexity of job and engagement in intellectual activities each accounted for less than 1% of variance at average age 62.

The findings suggest that the impact of education, occupational complexity and engagement in cognitive activities on later life cognitive function simply reflects earlier cognitive ability.

The researchers speculated that the role of education in increasing GCA takes place primarily during childhood and adolescence when there is still substantial brain development.

https://www.eurekalert.org/pub_releases/2019-01/uoc--yca011819.php

Reference: 

[4484] Crimmins, E. M., Saito Y., Kim J. Ki, Zhang Y. S., Sasson I., & Hayward M. D.
(2018).  Educational Differences in the Prevalence of Dementia and Life Expectancy with Dementia: Changes from 2000 to 2010.
The Journals of Gerontology: Series B. 73(suppl_1), S20 - S28.

Guerra-Carrillo, B., Katovich, K., & Bunge, S. A. (2017). Does higher education hone cognitive functioning and learning efficacy? Findings from a large and diverse sample. PLOS ONE, 12(8), e0182276. https://doi.org/10.1371/journal.pone.0182276

[4485] Kremen, W. S., Beck A., Elman J. A., Gustavson D. E., Reynolds C. A., Tu X. M., et al.
(2019).  Influence of young adult cognitive ability and additional education on later-life cognition.
Proceedings of the National Academy of Sciences. 116(6), 2021.

Source: 

Topics: 

tags development: 

tags memworks: 

tags problems: 

tags strategies: 

Low social engagement linked to cognitive decline & dementia risk

  • A very large, very long-running British study found that higher social contact at age 60 was associated with a significantly lower risk of developing dementia.
  • A 3-year study of older adults found that lower social engagement was only associated with greater cognitive decline in those with higher amyloid-beta levels.

Socially active 60-year-olds face lower dementia risk

Data from the Whitehall II study, tracking 10,228 participants for 30 years, found that increased social contact at age 60 is associated with a significantly lower risk of developing dementia later in life. Someone who saw friends almost daily at age 60 was 12% less likely to develop dementia than someone who only saw one or two friends every few months.

While previous studies have found a link between social contact and dementia risk, the long follow-up in the present study strengthens the evidence that social engagement could protect people from dementia (rather than precursors of dementia bringing about a decline in social engagement).

https://www.eurekalert.org/pub_releases/2019-08/ucl-sa6073119.php

Low social engagement plus high amyloid linked to cognitive decline

A three-year study of 217 healthy older adults (63-89) enrolled in the Harvard Aging Brain Study, has found that higher amyloid-beta levels in combination with lower social engagement was associated with greater cognitive decline over three years. Lower social engagement wasn’t associated with cognitive decline in those with a lower amyloid-beta burden.

https://www.eurekalert.org/pub_releases/2019-06/bawh-scl062819.php

Reference: 

Sommerlad, A., Sabia, S., Singh-Manoux, A., Lewis, G., & Livingston, G. (2019). Association of social contact with dementia and cognition: 28-year follow-up of the Whitehall II cohort study. PLOS Medicine, 16(8), e1002862. https://doi.org/10.1371/journal.pmed.1002862

Biddle, K et al, "Social Engagement and Amyloid-b-Related Cognitive Decline in Cognitively Normal Older Adults." American Journal of Geriatric Psychiatry. DOI: https://doi.org/10.1016/j.jagp.2019.05.005

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

Hearing loss linked to increased cognitive decline & dementia risk

  • A very large Taiwanese study found that adults with hearing loss had a higher dementia risk, and this was particularly so for those aged 45-64.
  • A very large Japanese study found that a dramatically greater proportion of older adults (65+) with hearing loss reported memory loss, compared to much fewer of those without hearing loss.
  • A very large study found that older adults (50+) who used hearing aids for hearing loss showed better performance on tests of working memory and attention compared with those who didn't use hearing aids for their hearing loss.
  • A large long-running study found that, while hearing impairment was associated with accelerated cognitive decline in older adults (mean age 73.5), the impact might be lessened by higher education.
  • A very large 8-year study found that hearing loss was associated with higher risk of subjective cognitive decline in older men (62+).
  • A very small study suggests that cognitive problems in some older adults may derive directly from hearing impairments, and may be fixed by addressing this.
  • A large, long-running study found that eating a healthy diet was associated with a lower risk of acquired hearing loss in women.

Hearing loss linked to increased dementia risk

A Taiwanese study involving 16,270 adults, of whom half had newly diagnosed hearing loss, found that those with hearing loss had a higher risk of dementia, particularly among those aged 45-64. Six comorbidities (cerebrovascular disease, diabetes, anxiety, depression, alcohol-related illnesses, and head injury) were also significantly associated with a higher dementia risk.

Among the study participants, 1,868 developed dementia during the 13-year study period.

https://www.eurekalert.org/pub_releases/2019-07/jn-hld072919.php

Hearing loss linked to limitations, distress, and memory loss in older people

Data from the 2016 Comprehensive Survey of Living Conditions of Japan has found that, of those 137,723 respondents who were aged 65 or older, about 9% reported hearing loss. There were substantial differences between those with hearing loss and those without:

  • 28.9% of those with hearing loss reported limitations in outdoor activities such as shopping or travel, vs. 9.5% of those without hearing loss
  • 39.7% of those with hearing loss reported psychological distress, vs 19.3%
  • 37.7% of those with hearing loss reported memory loss, vs only 5.2% of those without hearing loss.

https://www.eurekalert.org/pub_releases/2019-07/uot-hlt071919.php

Wearing hearing aid may help protect brain in later life

Data from the PROTECT online study of 25,000 older adults (50+) has found that those who wear a hearing aid for age-related hearing problems maintain better brain function over time than those who do not.

Participants undertook annual cognitive tests over two years. After that time, the group who wore hearing aids performed better in measures assessing working memory and aspects of attention than those who did not.

The findings were presented at the 2019 annual Alzheimer's Association International Conference, Los Angeles.

https://www.eurekalert.org/pub_releases/2019-07/uoe-wha071219.php

Hearing loss linked to greater cognitive decline but education mitigates effect

A large, long-running study, involving 1,164 older adults (mean age 73.5), found that, while hearing impairment was associated with accelerated cognitive decline, the impact might be lessened by higher education.

The study found that almost half of the participants (49.8%) had mild hearing impairment, with 16.8% suffering moderate-to-severe hearing loss. Those with more serious hearing impairment showed worse performance on the MMSE and the Trail-Making Test, Part B. Hearing impairment was also associated with greater decline in performance over time, for both the mildly and more severely impaired.

However, the association of mild hearing impairment with rate of cognitive decline was found only among those without a college education, while moderate-to-severe hearing impairment was associated with steeper MMSE decline regardless of education level.

Somewhat surprisingly, degree of social engagement did not affect the association of hearing impairment with cognitive decline.

https://www.eurekalert.org/pub_releases/2019-02/uoc--wac021219.php

Male hearing loss linked to cognitive decline

An eight-year longitudinal study among 10,107 older men (62+) found that hearing loss was associated with higher risk of subjective cognitive decline.

Compared with men with no hearing loss, the relative risk of cognitive decline was 30% higher among men with mild hearing loss, 42% higher among men with moderate hearing loss, and 54% higher among men with severe hearing loss but who did not use hearing aids. While those who did use hearing aids showed a reduced risk of cognitive decline (37%), this wasn’t statistically significant (not enough men in these groups, I assume).

The men were all health professionals. Subjective cognitive function was assessed using a six-item questionnaire, which was administered three times, at four-yearly intervals.

https://www.eurekalert.org/pub_releases/2019-01/bawh-etc012819.php

Signs of memory problems could be symptoms of hearing loss instead

A very small study found that 11 out of 20 participants being evaluated for cognitive concerns had some form of mild to severe hearing loss, but only 4 of them used hearing aids. A quarter of the participants didn’t show any signs of memory loss due to a brain disorder. It’s suggested that, for some, cognitive problems may derive directly from hearing impairments, and can be fixed by addressing this issue.

Hearing loss is the third most common chronic health condition in older adults, which is experienced by 50% of individuals over the age of 65 and 90% of people over the age of 80. It takes an average of 10 years before people seek treatment and fewer than 25% of those who need hearing aids will buy them.

https://www.eurekalert.org/pub_releases/2019-01/bcfg-som011819.php

Healthy diet may lower risk of hearing loss in women

A large, long-running study (the Nurses' Health Study II ) has found that eating a healthy diet was associated with a lower risk of acquired hearing loss in women. Women whose diets most closely resembled the AMED or DASH dietary patterns had an approximately 30% lower risk of moderate or worse hearing loss, compared with women whose diets resembled these dietary patterns the least.

The Alternate Mediterranean diet (AMED) diet includes extra virgin olive oil, grains, legumes, vegetables, fruits, nuts, fish and moderate intake of alcohol. The Dietary Approaches to Stop Hypertension (DASH) diet is high in fruits and vegetables and low-fat dairy, and low in sodium.

https://www.eurekalert.org/pub_releases/2018-05/bawh-hdm051118.php

Reference: 

[4479] Liu, C-M., & Lee C. Tzu- Chi
(2019).  Association of Hearing Loss With Dementia.
JAMA Network Open. 2(7), e198112 - e198112.

Iwagami, M., Kobayashi, Y., Tsukazaki, E., Watanabe, T., Sugiyama, T., Wada, T., … Tamiya, N. (2019). Associations between self-reported hearing loss and outdoor activity limitations, psychological distress and self-reported memory loss among older people: Analysis of the 2016 Comprehensive Survey of Living Conditions in Japan. Geriatrics & Gerontology International, 19(8), 747–754. https://doi.org/10.1111/ggi.13708

Alattar, A. A., Bergstrom, J., Laughlin, G. A., Kritz-Silverstein, D., Richard, E. L., Reas, E. T., … McEvoy, L. K. (n.d.). Hearing impairment and cognitive decline in older, community-dwelling adults. The Journals of Gerontology: Series A. https://doi.org/10.1093/gerona/glz035

Curhan, S et al. Longitudinal study of hearing loss and subjective cognitive function decline in men. Alzheimer's & Dementia DOI: 10.1016/j.jalz.2018.11.004

Dupuis, K., Yusupov, I., Vandermorris, S., Murphy, K., Rewilak, D., Stokes, K., & Reed, M. (2019). Considering Age-Related Hearing Loss in Neuropsychological Practice: Findings from a Feasibility Study. Canadian Journal on Aging / La Revue Canadienne Du Vieillissement, 38(2), 245-252. doi:10.1017/S0714980818000557

[4480] Curhan, S. G., Wang M., Eavey R. D., Stampfer M. J., & Curhan G. C.
(2018).  Adherence to Healthful Dietary Patterns Is Associated with Lower Risk of Hearing Loss in Women.
The Journal of Nutrition. 148(6), 944 - 951.

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

More studies linking poor sleep to Alzheimer's risk

  • Adults whose sleep quality declined in their 40s and 50s had more amyloid-beta in their brains later in life, while those reporting poorer sleep in their 50s and 60s had more tau tangles.
  • Greater tau protein was associated with less synchronized brainwaves during sleep.
  • Both amyloid-beta and tau levels increase dramatically after a single night of sleep deprivation, suggesting good sleep helps remove these proteins.
  • A large study found that older adults who consistently slept more than nine hours every night had twice the risk of developing dementia and Alzheimer’s disease within the next 10 years.
  • A large Japanese study found that those with sleep durations of less than 5 hours or more than 10 hours were more likely to develop dementia. However, those with short sleep could mitigate the effect with high physical activity.
  • A largish 12-year study found that poorer REM sleep was associated with an increased dementia risk.
  • Sleep apnea has been linked to higher levels of tau in the entorhinal cortex, poorer attention and memory, and slower processing speed.
  • Those with the APOE4 gene may be particularly vulnerable to the ill effects of sleep apnea.

Disrupted sleep in one's 50s, 60s raises Alzheimer's risk

A study involving 95 healthy older adults found that adults reporting a decline in sleep quality in their 40s and 50s had more amyloid-beta in their brains later in life, while those reporting poorer sleep in their 50s and 60s had more tau tangles. Those with high levels of tau protein were more likely to lack the synchronized brain waves during deep NREM sleep that are associated with a good night's sleep, and the more tau protein, the less synchronized these brain waves were.

Previous research has found that a dip in the amplitude of slow wave activity during deep NREM sleep was associated with higher amounts of beta-amyloid in the brain and memory impairment.

https://www.eurekalert.org/pub_releases/2019-06/uoc--dsi062619.php

Studies of healthy animals and humans have reported higher levels of amyloid beta after a single night of sleep deprivation, and that disruption of slow-wave sleep causes amyloid beta levels to rise as much as 30%. Moreover, a single night’s sleep deprivation has been found to increase tau levels by as much as 50% in cerebrospinal fluid.

These findings suggest that quality sleep helps the body clear excess amyloid and tau proteins.

https://www.eurekalert.org/pub_releases/2019-03/aps-spa032119.php

A preliminary study involving 20 healthy subjects aged 22 to 72 found beta-amyloid increases of about 5% after losing a night of sleep.

Many researchers believe the link between sleep disorders and Alzheimer's risk is "bidirectional," since elevated beta-amyloid may also lead to sleep disturbances.

https://www.eurekalert.org/pub_releases/2018-04/nioa-los041318.php

A very small study involving eight people aged 30-60, who experienced (over time) two or three different sleep situations, found that amyloid beta levels were 25-30% higher when individuals had a a sleepless night — putting those amyloid beta levels on par with the levels seen in people genetically predisposed to develop Alzheimer’s at a young age.

http://www.futurity.org/sleep-alzheimers-amyloid-beta-1642332/

A sleep study involving 17 healthy adults aged 35 to 65, found that those whose slow-wave sleep was disrupted (by a beeping sound that moved them into a shallower sleep) found a 10% increase in amyloid beta levels after a single night of interrupted sleep, but no corresponding increase in tau levels. However, participants whose activity monitors showed they had slept poorly at home for the week before showed a spike in levels of tau.

http://www.futurity.org/sleep-alzheimers-proteins-1485152-2/

https://www.theguardian.com/science/2017/jul/10/poor-sleep-increases-risk-of-alzheimers-research-reveals

Is too much sleep an early sign of dementia?

Data from 2,457 older adults (65+) in the Framingham study found that those who consistently slept more than nine hours every night had twice the risk of developing dementia and Alzheimer’s disease within the next 10 years, compared to those who slept less than nine hours a night.

Over the 10-year study period, 234 were diagnosed with dementia.

It’s suggested that one reason might be that those with depression tend to sleep longer. In any case, it’s thought that the longer sleep sessions reflect something else going on, rather than being a cause.

Education level also affected the degree of risk. Those without a high school degree who slept more than nine hours nightly had a 600% greater risk of later receiving a dementia diagnosis than people with a high school degree.

http://www.futurity.org/too-much-sleep-dementia-1439122/

Optimal sleep linked to lower dementia risk

A ten-year Japanese study involving 1,517 older adults (60+) found that dementia rates were higher in those with daily sleep duration of less than 5 hours or more than 10 hours, compared with those with daily sleep duration of 5-6.9 hours. However, those with short sleep duration who had high physical activity did not have a greater risk of dementia.

294 participants (19%) developed dementia in the 10 year period.

https://www.eurekalert.org/pub_releases/2018-06/w-osl060518.php

Lack of REM sleep linked to higher dementia risk

A study involving 321 older adults (60+; average age 67), who participated in a sleep study between 1995 and 1998, found poorer REM sleep was associated with an increased risk of developing dementia over 12 years.

During that period, 32 people were diagnosed with some form of dementia (24 with Alzheimer’s)

Those who developed dementia spent an average of 17% of their sleep time in REM sleep, compared with 20% for those who didn’t develop dementia. For every percent that REM sleep was reduced, there was a 9% increase in dementia risk, and an 8% increase in Alzheimer’s risk specifically.

No such associations were found for other stages of sleep, although that shouldn’t be taken to mean that other sleep stages don’t affect key features of Alzheimer’s.

http://www.futurity.org/rem-sleep-dementia-risk-1524842/

Sleep apnea linked to higher tau levels

A study involving 288 cognitively healthy older adults (65+) found that those who had sleep apneas had on average 4.5% higher levels of tau in the entorhinal cortex than those who did not have apneas, after controlling for several other factors that could affect levels of tau in the brain, such as age, sex, education, cardiovascular risk factors and other sleep complaints.

15% (43 participants) were reported by their bed partners as having sleep apneas.

This preliminary study was presented at the American Academy of Neurology's 71st Annual Meeting in Philadelphia, May 4-10, 2019.

https://www.eurekalert.org/pub_releases/2019-03/aaon-sam022619.php

Data from 1,752 older adults found that sleep-disordered breathing was associated with poorer attention and processing speed. In particular, increased overnight hypoxemia (oxygen saturation below 90%) was linked with poorer attention and memory, and more daytime sleepiness associated with poorer attention and memory and slower cognitive processing speed.

These associations were strongest in APOE-ε4 carriers.

https://www.eurekalert.org/pub_releases/2017-07/ats-sdm071817.php

Reference: 

[4468] Winer, J. R., Mander B. A., Helfrich R. F., Maass A., Harrison T. M., Baker S. L., et al.
(2019).  Sleep as a Potential Biomarker of Tau and β-Amyloid Burden in the Human Brain.
Journal of Neuroscience. 39(32), 6315 - 6324.

[4469] Ning, S., & Jorfi M.
(2019).  Beyond the sleep-amyloid interactions in Alzheimer’s disease pathogenesis.
Journal of Neurophysiology. 122(1), 1 - 4.

[4413] Shokri-Kojori, E., Wang G-J., Wiers C. E., Demiral S. B., Guo M., Kim S. Won, et al.
(2018).  β-Amyloid accumulation in the human brain after one night of sleep deprivation.
Proceedings of the National Academy of Sciences. 115(17), 4483 - 4488.

[4470] Lucey, B. P., Hicks T. J., McLeland J. S., Toedebusch C. D., Boyd J., Elbert D. L., et al.
(2018).  Effect of sleep on overnight cerebrospinal fluid amyloid β kinetics.
Annals of Neurology. 83(1), 197 - 204.

[4471] Ju, Y-E. S., Ooms S. J., Sutphen C., Macauley S. L., Zangrilli M. A., Jerome G., et al.
(2017).  Slow wave sleep disruption increases cerebrospinal fluid amyloid-β levels.
Brain. 140(8), 2104 - 2111.

[4438] Westwood, A. J., Beiser A., Jain N., Himali J. J., DeCarli C., Auerbach S. H., et al.
(2017).  Prolonged sleep duration as a marker of early neurodegeneration predicting incident dementia.
Neurology. 88(12), 1172.

[4473] Ohara, T., Honda T., Hata J., Yoshida D., Mukai N., Hirakawa Y., et al.
(2018).  Association Between Daily Sleep Duration and Risk of Dementia and Mortality in a Japanese Community.
Journal of the American Geriatrics Society. 66(10), 1911 - 1918.

[4474] Pase, M. P., Himali J. J., Grima N. A., Beiser A. S., Satizabal C. L., Aparicio H. J., et al.
(2017).  Sleep architecture and the risk of incident dementia in the community.
Neurology. 89(12), 1244.

[4472] Johnson, D. A., Lane J., Wang R., Reid M., Djonlagic I., Fitzpatrick A. L., et al.
(2017).  Greater Cognitive Deficits with Sleep-disordered Breathing among Individuals with Genetic Susceptibility to Alzheimer Disease. The Multi-Ethnic Study of Atherosclerosis.
Annals of the American Thoracic Society. 14(11), 1697 - 1705.

 

Topics: 

tags lifestyle: 

tags problems: 

Pages

Subscribe to RSS - risk factors
Error | About memory

Error

The website encountered an unexpected error. Please try again later.