Risk factors for Alzheimer's Disease: Other than dietary

Risk factors

Genes

Maternal inheritance more importance than paternal for Alzheimer's risk?

Familial link between Parkinson's and dementia

High stress and genetic risk factor lead to increased memory decline

New Alzheimer's gene

Study examines genetic risk factors for Alzheimer's disease

Two-fold role of Alzheimer’s genes?

Alzheimer's has higher genetic risk than thought

Key genetic risk for Alzheimer's linked to myelin breakdown

Genes influence memory in families with Alzheimer's disease

Genes identified for age of onset of Alzheimer's

New genetic risk factor for susceptibility to Alzheimer's disease

Gene marker for late-onset Alzheimer's disease nearer discovery

November 2007

Maternal inheritance more importance than paternal for Alzheimer's risk?

In an intriguing preliminary study comparing brain metabolism among cognitively normal people who have a father, a mother, or no relatives with Alzheimer’s disease, researchers have found that only those with an affected mother have reduced brain metabolism in the same brain regions as Alzheimer’s patients.
The study was published in the November 27 issue of Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2007-11/nyum-aml110607.php

October 2007

Familial link between Parkinson's and dementia

A study of relatives of patients with Parkinson’s disease provides evidence that relatives of patients with Parkinson’s disease (primarily younger age at onset Parkinson’s) have an increased risk of cognitive impairment or dementia.
The report appeared in the October issue of Archives of Neurology.   Full reference
http://www.eurekalert.org/pub_releases/2007-10/jaaj-rop100407.php

August 2007

High stress and genetic risk factor lead to increased memory decline

A study involving 91 older, healthy subjects (mean age 78.8 years) has found that those low on stress (low levels in cortisol) or without the APOE-ε4 gene performed better on memory measures than those with high stress or those with the APOE-ε4 gene. Those who had the gene and had high stress levels showed the greatest memory impairment.
The study was published in the September 1st issue of Biological Psychiatry.  Full reference
http://www.eurekalert.org/pub_releases/2007-08/e-naf082707.php

June 2007

New Alzheimer's gene

A study comparing more genetic markers in the DNA of people with and without Alzheimer’s disease than ever before has revealed a new gene that may increase a person’s risk for developing Alzheimer’s disease. The gene — GAB2 — appears to modify an individual’s risk when associated with other genes, including APOE4. It’s suggested that the healthy form of the GAB2 gene protects brain cells from developing tangles. If confirmed, this discovery could provide a target for future therapeutic drugs.
The results appeared in the June 7 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2007-06/ttgr-rti060107.htm

March 2007

Study examines genetic risk factors for Alzheimer's disease

A Welsh study that tested more than 17,000 gene variants in 4,000 volunteers has found evidence for several genes contributing to Alzheimer’s disease, the most interesting one being GALP, thought to affect the development of tangles within brain cells.
The findings will be published in a future issue of Human Molecular Genetics. http://www.eurekalert.org/pub_releases/2007-03/cu-seg030507.htm

September 2006

Two-fold role of Alzheimer’s genes?

The genes responsible for an inherited form of Alzheimer's disease — two genes known as presenilins — are primarily known for their role as an enzyme that cleaves amyloid precursor protein (APP) to form amyloid ß-peptide, which function has a direct connection to Alzheimer’s, and consequently has been the focus of attention. However, new research indicates that these genes also may control the balance of calcium within cells by acting as a calcium channel, and that the mutated forms of these genes lose this ability. Given the role that calcium signaling plays in cognitive function, it may be that this other role of presenilins is also important in the development of Alzheimer’s. If so, drugs that restore normal calcium levels might be useful for treating Alzheimer's disease.
The report appeared in the September 8 issue of Cell. Full reference
http://www.eurekalert.org/pub_releases/2006-09/cp-ssa090106.htm

February 2006

Alzheimer's has higher genetic risk than thought

In a study far larger than any undertaken before, results suggest the highest estimates of the genetic risk of developing Alzheimer’s are in fact correct. The study involved all participants in the Swedish Twin Registry aged 65 or older in 1998 (nearly 12,000 of them) and found 392 pairs with evidence of Alzheimer's in at least one twin. In the model that best fit the data, genetic influence accounted for 79% of Alzheimer's risk, with 95% probability of being within the range 67 to 88%. The other 21% of Alzheimer's risk was due to non- shared environmental causes. Risk from shared environments was statistically negligible. Genetic risk for Alzheimer's was the same for men and women after controlling for age. The study raises doubts about the widely held view that Alzheimer's has two forms: the "familial," with genetic roots, and the "sporadic," with environmental causes. This doesn’t mean, however, that environment is unimportant.
The study appeared in the February 2006 issue of Archives of General Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2006-02/uosc-aft020206.htm

January 2006

Key genetic risk for Alzheimer's linked to myelin breakdown

Myelin, the fatty insulation coating the brain's internal wiring, builds up in childhood, and breaks down as we age. Myelin is critical for speedy communication between neurons. A new study supports a growing body of evidence that myelin breakdown is a key contributor to the onset of Alzheimer disease later in life. Moreover, it has also revealed that the severity and rate of myelin breakdown in healthy older individuals is associated with ApoE status. Thus both age, the most important risk factor for Alzheimer disease, and ApoE status, the second-most important risk factor, seem to act through the process of myelin breakdown.
The findings are detailed in the January edition of Archives of General Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2006-01/uoc--isl122805.htm

February 2004

Genes influence memory in families with Alzheimer's disease

A study of 1,036 people from 266 families, most of whom had more than one person living with Alzheimer's in the extended family, found that about half of the variation in memory performance among individuals was due to genetics. The influence of genetics was not as strong in the areas of attention, abstract reasoning, language and visual-spatial ability. The genetic influence seemed to have little to do with the gene apolipoprotein E, known to increase the risk of developing Alzheimer's. It should be noted, however, that participants in the study had an average of only six years of education.
The study was published in the February 10 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2004-02/aaon-gim020304.htm

February 2002

Genes identified for age of onset of Alzheimer's

Genes responsible for controlling the age of onset of Alzheimer's or Parkinson's diseases in those individuals genetically predisposed to developing these diseases have been identified. It appears that chromosome 10, already thought to contain a risk gene for Alzheimer's disease, could also contain an age at onset gene that affects both Alzheimer's and Parkinson's diseases.
The study appears in the April issue of American Journal of Human Genetics. Full reference
http://www.eurekalert.org/pub_releases/2002-02/dumc-dri022502.htm

June 2001

New genetic risk factor for susceptibility to Alzheimer's disease

In a decade-long research study following more than 300 first-degree relatives of 189 Alzheimer's patients, researchers at the University of Pittsburgh have identified a small area of chromosome 10 that, when combined with the previously identified APOE E4 gene, significantly increase a person's risk of developing the disease. This combination of genes produced a 16-fold increase in the risk of AD among first-degree relatives. By comparison, this effect is greater than the increased risk of lung cancer caused by smoking. These new results are supported by independent studies of AD patients and controls from Pittsburgh, Boston, and Bonn, Germany.
The study was reported in Molecular Psychiatry, 6 (4), pages 413-419.
http://www.eurekalert.org/pub_releases/2001-06/MP-Ngrf-1706101.htm

Gene marker for late-onset Alzheimer's disease nearer discovery

Three independent studies have linked late-onset Alzheimer's disease to a locus on chromosome 10 that affects processing of the amyloid-beta protein, a peptide important in the formation of the characteristic amyloid plaques found in the brains of people with Alzheimer's disease. Researchers are optimistic the precise gene will be found in the next few years.
Before this, a particular form of the apolipoprotein E (APOE) gene on chromosome 19 has been the only widely recognized genetic risk factor in late onset Alzheimer’s disease. There is also some evidence of a risk factor gene on a region of chromosome 12.
So far, three genes have been found that are linked to the rare early-onset Alzheimer's (when symptoms appear before age 60).
The findings are reported in the Dec. 22 issue of Science.
http://www.eurekalert.org/pub_releases/2000-12/MCJ-Loc1-2112100.htm

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Other

Not finishing high school may lead to memory problems

Smokers are more likely to develop dementia

High stress and genetic risk factor lead to increased memory decline

Distress-prone people more likely to develop memory problems

Estrogen use before 65 linked to reduced risk of Alzheimer's disease

Secondhand smoke increases risk of dementia

Inhaled anesthetics might increase the risk of Alzheimer's

Loneliness increases risk of Alzheimer's disease

Anesthetics a risk factor for Alzheimer’s?

Depression associated with changes in the brain in Alzheimer's

Brain activity, drugs could affect Alzheimer's progression

New research suggests heart bypass surgery increases risk of Alzheimer's disease

Smoking now found detrimental for Alzheimer's

Testosterone loss may lead to Alzheimer's

Coronary artery bypass surgery not a risk factor for dementia

Minorities hardest hit by Alzheimer's disease

Low free testosterone levels linked to Alzheimer's disease in older men

Distress-prone people more likely to develop Alzheimer's disease

Study points to depression as a risk for developing Alzheimer's disease

Early language ability may be linked to lower risk of Alzheimer's

October 2007

Not finishing high school may lead to memory problems

A long-running Finnish study has found that compared with people with five or less years of education, those with six to eight years had a 40% lower risk of developing dementia and those with nine or more years had an 80% lower risk. Generally speaking, people with low education levels seemed to lead unhealthier lifestyles, but the association remained after lifestyle choices and characteristics such as income, occupation, physical activity and smoking had been taken into account.
The study was published in the October 2 issue of Neurology.    Full reference
http://www.eurekalert.org/pub_releases/2007-10/aaon-nfh092507.php

September 2007

Smokers are more likely to develop dementia

A seven-year study of some 7,000 people age 55 and older found that those who were current smokers at the time of the study were 50% more likely to develop dementia than people who had never smoked or past smokers. Smoking did not increase the risk for those with the Alzheimer’s gene apolipoprotein E4. Current smokers without the gene were nearly 70% more likely to develop Alzheimer’s than nonsmokers or past smokers without the gene.
The study was published in the September 4 issue of Neurology.   Full reference
http://www.eurekalert.org/pub_releases/2007-09/aaon-sam082807.php

August 2007

High stress and genetic risk factor lead to increased memory decline

A study involving 91 older, healthy subjects (mean age 78.8 years) has found that those low on stress (low levels in cortisol) or without the APOE-ε4 gene performed better on memory measures than those with high stress or those with the APOE-ε4 gene. Those who had the gene and had high stress levels showed the greatest memory impairment.
The study was published in the September 1st issue of Biological Psychiatry.  Full reference
http://www.eurekalert.org/pub_releases/2007-08/e-naf082707.php

June 2007

Distress-prone people more likely to develop memory problems

Data from two large, long-running studies, the Religious Orders Study and the Memory and Aging Project, has revealed that those who most often experience negative emotions such as depression and anxiety (according to self report) were 40% more likely to develop mild cognitive impairment than those who were least prone to negative emotions. This follows on from an earlier study showing that people who are easily distressed are more likely to develop Alzheimer’s disease than more easygoing people.
The study was published in the June 12 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2007-06/aaon-dpm060507.htm

May 2007

Estrogen use before 65 linked to reduced risk of Alzheimer's disease

Data from the Women’s Health Initiative Memory Study looked at prior hormone use in 7,153 healthy women ages 65-79 before they enrolled in the WHI Memory Study, and followed their cognitive health over an average of five years. In that time, 106 of the women developed Alzheimer’s disease or dementia. The study found women who used any form of estrogen hormone therapy before the age of 65 were nearly 50% less likely to develop Alzheimer’s disease or dementia than women who did not use hormone therapy before age 65, but women who began estrogen-only therapy after the age of 65 had roughly a 50% increased risk of developing dementia. The risk jumped to nearly double for women using estrogen-plus-progestin hormone therapy.
The findings were presented at the American Academy of Neurology’s 59th Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-eub041007.htm

Secondhand smoke increases risk of dementia

Preliminary findings from the Cardiovascular Health Study indicates that elderly people with high lifetime exposure to secondhand smoke (more than 30 years) were approximately 30% more likely to develop dementia than those with no lifetime secondhand smoke exposure. People with abnormalities of their carotid arteries and high lifetime exposure to secondhand smoke were nearly two-and-a-half times as likely to develop dementia as those with no secondhand smoke exposure and no indications of carotid artery disease.
Haight presented the findings at the American Academy of Neurology’s 59th Annual Meeting in Boston, April 28 – May 5, 2007.
http://www.eurekalert.org/pub_releases/2007-05/aaon-ssi041007.htm

February 2007

Loneliness increases risk of Alzheimer's disease

Social isolation has been linked with an increased risk of dementia and cognitive decline, but perceived isolation — feeling alone rather than being alone — hasn’t been investigated. A new four-year study of 823 older adults provides evidence that loneliness is a risk factor for Alzheimer’s. 76 individuals developed Alzheimer’s over the course of the study, and the risk of developing it increased around 51% for each point on the 5-point loneliness score. The findings did not change significantly when the researchers factored in markers of social isolations, such as a small network and infrequent social activities. Autopsies performed on 90 individuals who died during the study show that loneliness is a risk factor rather than an early sign of the disease.
The study was published in the February issue of Archives of General Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2007-02/rumc-law020207.htm

Inhaled anesthetics might increase the risk of Alzheimer's

A study using a new imaging technique has been able to see why anesthetics might cause amyloid β peptides to clump together, and whether one method of anesthesia was better than another. Previous studies have found that the inhaled anesthetics halothane and isoflurane and the intravenous anesthetic propofol encouraged the growth and clumping of Aβ in a test tube experiment. The new study found that the inhaled anesthetics caused the highest levels of Aβ aggregation, while the injected anesthetic propofol only interacted and caused aggregation at high concentrations, and thiopental did not cause the clustering of Aβ peptides even at high concentrations.
The study was published in the January 23 issue of Biochemistry. Full reference
http://www.eurekalert.org/pub_releases/2007-01/uopm-roa012507.htm

October 2006

Anesthetics a risk factor for Alzheimer’s?

The link between surgery and cognitive problems has long been noted, but it’s never been clear whether postoperative cognitive dysfunction was the result of the surgery itself or the anaesthetics. Now animal studies and test tube experiments are beginning to show that certain anaesthetics reduce the rate at which brain cells are born and develop. The latest study reveals that the inhaled anaesthetics halothane and isoflurane encourage clumping of beta amyloid protein, as does the commonly used intravenous anaesthetic propofol, at least at higher concentrations — suggesting that giving elderly patients certain general anaesthetics could increase their risk of developing Alzheimer's disease. The intravenous anaesthetic thiopental appears to have no effect on the proteins.
The study was presented at the annual Society for Neuroscience Meeting held in Atlanta, Georgia, October 14-18.
http://www.newscientist.com/channel/health/mg19225753.900-alzheimers-alert-over-anaesthetics.html
http://www.eurekalert.org/pub_releases/2006-10/ns-aao102506.htm

February 2006

Depression associated with changes in the brain in Alzheimer's

A lifetime history of depression is associated with increased plaques and tangles in the brains of those with Alzheimer's disease and more rapid cognitive decline, confirming previous indications that depression may be a risk factor for Alzheimer’s.
The study is published in the February issue of Archives of General Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2006-02/tmsh-ldb020306.htm

December 2005

Brain activity, drugs could affect Alzheimer's progression

Mouse studies have revealed that the activity of connections among brain cells significantly affects levels of the toxic protein beta-amyloid, suggesting that the kind of mental activity people practice or drugs they might take for depression or anxiety could affect their risk of Alzheimer’s or the disease progression. The researchers suggest that enriched environments may increase overall synaptic activity in some brain regions and decrease it in others. Increased activity in some brain regions might result in increased susceptibility to beta-amyloid deposition if the activated neural circuits contain high levels of human APP expression. Drugs used to treat neuropsychiatric disorders directly influence neurotransmitters, and their receptors, thereby altering synaptic activity.
The article appeared in the December 22 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2005-12/cp-bad121505.htm

August 2005

New research suggests heart bypass surgery increases risk of Alzheimer's disease

Patients who have either coronary artery bypass graft surgery or coronary angioplasty are at an increased risk of developing Alzheimer's disease, according to a study involving 5,216 people who underwent coronary artery bypass graft surgery (CABG) and 3,954 people who had a percutaneous transluminal coronary angioplasty (PTCA) in 1996 and 1997. The researchers suggest the trauma to the brain during surgery is the principle cause.
The report appeared in the August issue of the Journal of Alzheimer's Disease. Full reference
http://www.eurekalert.org/pub_releases/2005-08/cwru-nrs082405.htm

February 2005

Smoking now found detrimental for Alzheimer’s

Previous animal studies had suggested that nicotine reduces the number of amyloid plaques; a new study, however, has found that chronic nicotine exposure increases neurofibrillary tangles.
The paper appeared in the February 22 issue of Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-02/uoc--ctp020805.htm

September 2004

Testosterone loss may lead to Alzheimer's

A new study suggests that, like estrogen loss in older women, decreased levels of testosterone may put aging men at risk for Alzheimer's disease. The research suggests that testosterone both protects neurons from injury, and reduces levels of beta-amyloid.
The findings were reported in a letter to the editor in the September 22 issue of the Journal of American Medical Association. Full reference
http://www.eurekalert.org/pub_releases/2004-09/uosc-alm092104.htm

July 2004

Coronary artery bypass surgery not a risk factor for dementia

A comparison of dementia patients with controls has found that dementia patients are no more likely than those without dementia to have had coronary artery bypass surgery.
http://www.eurekalert.org/pub_releases/2004-07/mc-cab071504.htm

Minorities hardest hit by Alzheimer's disease

A study of 119 Latinos and 55 non-Latino white Alzheimer patients suggests that Latinos in the U.S. develop Alzheimer's symptoms much earlier than their white, non-Latino peers. There are several known factors which may be responsible for this apparent vulnerability in Latinos: high rates of vascular disease, leave school earlier, and less likely to use medical services or have health insurance than other Americans.

South Carolina, as the only U.S. state that keeps a comprehensive database of people with a diagnosis of Alzheimer's disease, has found that African Americans aged 55 to 64 years were more than three times as likely to have Alzheimer's as their European American counterparts. At ages 65 to 84, African Americans were more than twice as likely to have Alzheimer's. South Carolina has greater rates of obesity, diabetes, and related health problems than the rest of the country, especially amongst African Americans.

Another study has found that, in order to avoid overestimating the number of African Americans who may have early signs of Alzheimer's disease, screening tests must be adapted to cultural differences. The study involved 635 people over the age of 60. Researchers found that, using current scoring methods, African Americans scored lower on various neuropsychological tests. Even when education was taken into account, 35% of African Americans scored low enough to warrant a diagnosis of MCI, compared to only 15% of European Americans. However, when the researchers applied new, racially sensitive scoring methods they've developed, the difference in MCI rates disappeared.
References
http://www.eurekalert.org/pub_releases/2004-07/aa-mhh070704.htm

Alzheimer's Association offers information about providing culturally sensitive care at http://www.alz.org//Resources/Diversity/

January 2004

Low free testosterone levels linked to Alzheimer's disease in older men

A study evaluating the testosterone levels of 574 men, ages 32 to 87, who participated in the Baltimore Longitudinal Study of Aging (BLSA), found that older men with lower levels of free, or unbound, testosterone circulating in their bloodstreams were apparently at higher risk of developing Alzheimer's than their peers. This is believed to be the first study to associate low circulating blood levels of free testosterone with Alzheimer’s years before diagnosis. Previously, the same researchers had found that older men with high levels of circulating free testosterone have better visual and verbal memory and perform spatial tasks more adeptly than their peers.
The study appeared in the January 27 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2004-01/naos-lft012804.htm

December 2003

Distress-prone people more likely to develop Alzheimer's disease

The Religious Orders Study has found that those who most often experience negative emotions like depression and anxiety were twice as likely to develop Alzheimer's disease as those who were least prone to experience negative emotions. A person’s tendency to experience psychological distress has been shown to be a stable personality trait throughout adulthood. Proneness to stress was specifically associated with a decline in episodic memory (measured by asking participants to recall a list of words or a story) — an area particularly problematic for those with Alzheimer's. Episodic memory ability declined 10 times faster in those high in proneness to distress than in those low in this response. This result was not altered when participants’ engagement in cognitively stimulating activities. Examination of the brains of those who have died during the long-term study appears to rule out the possibility that proneness to distress is an early sign of Alzheimer's disease rather than a risk factor, although more research is needed to confirm this.
The study was published in the December 9 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2003-12/aaon-pm120203.htm

August 2002

Study points to depression as a risk for developing Alzheimer's disease

More than 650 elderly people took part in a seven-year study which has revealed that those with the greatest number of depressive symptoms at the start of the study were more likely to develop Alzheimer's disease and also showed more rapid cognitive decline.
The study was published in the August 13 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2002-08/aaon-spt080502.htm

Early language ability may be linked to lower risk of Alzheimer's

The " Nun Study" has followed 678 Catholic nuns from 7 convents of the School Sisters of Notre Dame for 15 years. The stability and similarity of their lives makes them wonderful subjects, and the duration of the project means that it began when many were too young to manifest Alzheimer's or other diseases related to aging. Particularly helpful in this regard is that the sisters were required to write autobiographical essays when they took their vows in their 20's.
The research has shown that folic acid may help stave off Alzheimer's disease; that small, barely perceptible strokes may trigger some dementia; and, in an especially striking finding, that early language ability may be linked to lower risk of Alzheimer's because nuns who packed more ideas into the sentences of their early autobiographies were less likely to get Alzheimer's disease six decades later.
The latest report says nuns who expressed more positive emotions in their autobiographies lived significantly longer — in some cases 10 years longer — than those expressing fewer positive emotions.
The report was published in the Journal of Personality and Social Psychology.
http://www.nytimes.com/2001/05/07/health/07NUNS.html
An excerpt from "Aging with Grace: The School Sisters of Notre Dame Study" by Sharon M. Reynold can be found at: http://www.mc.uky.edu/nunnet/saints.htm

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