Social interaction reduces dementia risk and increases longevity

by University of New South Wales

Credit: CC0 Public Domain

Spending time with loved ones can have significant health benefits as we age, according to a new meta-analysis study from the Centre for Healthy Brain Ageing (CHeBA) at UNSW Sydney.

10 may 2023--The researchers studied the link between social connections in older people and the risk of mild cognitive impairment (MCI), dementia and mortality. They pooled together the results of 13 international studies, which followed people aged 65 years and above over long periods of time.

The research is published today in Alzheimer's & Dementia.

"We know from previous research that social connections are important for our health and being isolated puts us at higher risk of dementia and death," said first author Dr. Suraj Samtani, who is a clinical psychologist and researcher at CHeBA.

"Our goal was to find which social connections protect us from dementia and death."

Studying aging populations

The researchers obtained results from studies in low, middle and high-income countries across the world. These included Australia, North America, and several nations in Europe, South America, Asia, and Africa. The study population is more diverse than previous meta-analyses, which have mainly focused on North America and Europe.

Then the researchers analyzed information about the social connections of the study participants. They were interested in the social connection type (e.g., being in a relationship or married, engaging with a community group), function (e.g., social support, having a confidante), and quality (e.g., level of relationship satisfaction).

Finally, the researchers looked at whether the participants developed MCI or dementia, or passed away, during the studies. They controlled for other variables which could influence these outcomes including age, sex, education level, lifestyle factors and other chronic diseases.

"We looked at social variables across these studies, such as living with others, interacting with friends and family, engaging in community activities, and social support," Dr. Samtani said. "We wanted to know which of these are associated with risk of getting dementia over time or dying."

Protective effects of social connections

Among the study participants, good social connections were associated with a lower risk of MCI, dementia and death.

"We found that frequent interactions—monthly or weekly—with family and friends and having someone to talk to reduced the risk of getting dementia. We also found that living with others and doing community activities reduced the risk of dying," Dr. Samtani said.

Why would social interaction be linked to MCI, dementia and death? Many other studies show that poor social connections are associated with poorer lifestyle and poorer health.

For example, close relationships can have a stress buffering effect, as we confide in and receive support from these individuals. Controlling stress is important for brain and overall health.

Another example is that our family, friends and community members may influence us to take on healthy behaviors. This phenomenon, exemplified by your friends dragging you to park run at 7am on a Saturday, is known as 'social contagion'.

One limitation of the findings is the 'chicken or the egg' problem. Participants who had already MCI or dementia at the beginning of the studies were excluded from the analysis. However, it is possible that they had some undetected cognitive and physical health issues. These could impact their social interactions, rather than the other way around.

Tips to stay healthy

The researchers recommend that we prioritize social connection to reduce risk of cognitive decline and live longer.

"Try to meet with friends and family at least once a month, take part in community activities like volunteering or a rotary club, and open your heart to someone when you feel stressed. Living with others, for example in an intergenerational household, is also helpful," Dr. Samtani said.

"Connecting with others helps us to keep our bodies and minds healthy."

The researchers at CHeBA are now looking at interventions to improve the social connections of older adults, to protect their brain and overall health. Dr. Samtani has recently been awarded a Dementia Australia Research Foundation post-doctoral fellowship to trial a social cognition intervention for older adults with memory concerns.

"We hope that helping people to stay engaged in conversations and maintain healthy friendships and relationships will help them to stay healthy and happy," Dr. Samtani said.

More information: Gowsaly Mahalingam et al, Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing, Alzheimer's & Dementia (2023). DOI: 10.1002/alz.13072

Living close to major roads linked to small increase in dementia risk

A study of over 6.5 million Ontario residents raises public health concerns about the impact of air pollution and noise. Credit: Public Health Ontario and the Institute for Clinical Evaluative Sciences

Dementia is more common in people who live within 50 metres of a major road than those who live further away, according to a study looking at 6.6 million people published in The Lancet. However, the study found no link between traffic exposure and Parkinson's disease or multiple sclerosis.

06 jan 2017--The observational study estimated that up to one in 10 (7-11%) cases of dementia among those who live within 50 metres of a major road could be attributed to traffic exposure.
Previous research has suggested that air pollution and traffic noise may contribute to neurodegeneration, with one study finding that living near a road was associated with reduced white matter and lower cognition. However, the paper in The Lancet is the first to investigate the link between living close to heavy traffic and the onset of major neurodegenerative diseases.
The researchers tracked all adults aged between 20 and 85 living in Ontario, Canada - approximately 6.6 million people - for over a decade from 2001 to 2012. They used postcodes to determine how close people lived to a road and analysed medical records to see if they went on to develop dementia, Parkinson's disease or multiple sclerosis.
Almost all people (95%) in the study lived within one kilometre of a major road and half lived within 200 metres of one. Over the study period, more than 243000 people developed dementia, 31500 people developed Parkinson's disease and 9250 people developed multiple sclerosis.
While there was no association between living near a road and Parkinson's disease or multiple sclerosis, dementia was more common the closer people lived to busy roads. The risk of developing dementia reduced as people lived further away from a main road - with a 7% higher risk in developing dementia among those living within 50 metres, a 4% higher risk at 50-100 metres, a 2% higher risk at 101-200 metres and no increase in risk in those living more than 200 metres away.
The researchers also found that long-term exposure to two common pollutants (nitrogen dioxide and fine particulate matter) was associated with dementia but this did not account for the full effect, meaning other factors are also likely to be involved. These could include other air pollutants or noise from traffic.
"Despite the growing impact of these diseases, little is known about their causes and prevention," said lead author Dr Hong Chen, Public Health Ontario, Canada. "Our study suggests that busy roads could be a source of environmental stressors that could give rise to the onset of dementia. Increasing population growth and urbanisation has placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden. More research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise."
The study estimated air pollution exposure based on postcode, so does not account for each individual's exposure. Because the study is observational it cannot establish causality, but the study was designed to control for socioeconomic status, education levels, BMI and smoking meaning the link is unlikely to be explained by these factors.
Writing in a linked Comment, Dr Lilian Calderón-Garcidueñas, University of Montana, USA, said: "The significant association of newly diagnosed cases of dementia in the study period between 2001 and 2012 with the proximity to traffic road less than 50 m-300 m versus more than 300 m, and the robust observation of dementia involving predominantly urban versus rural residents, opens up a crucial global health concern for millions of people... The health repercussions of living close to heavy traffic vary considerably among exposed populations, given that traffic includes exposures to complex mixtures of environmental insults... We must implement preventive measures now, rather than take reactive actions decades from now."

More information: The Lancet, www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)32399-6/fulltext


Provided by Lancet

Calcium supplements linked to dementia risk in women with certain health conditions

Credit: CC0 Public Domain

According to a new study, calcium supplements may be associated with an increased risk of dementia in older women who have had a stroke or other signs of cerebrovascular disease. The research is published in the August 17, 2016, online issue of Neurology, the medical journal of the American Academy of Neurology.

18 aug 2016--Cerebrovascular disease is a group of disorders that affect blood flow in the brain. These diseases, including stroke, are the fifth leading cause of death in the United States and increase the risk of developing dementia.
"Osteoporosis is a common problem in the elderly. Because calcium deficiency contributes to osteoporosis, daily calcium intake of 1000 to 1200 mg is recommended. Getting this recommended amount through diet alone can be difficult, so calcium supplements are widely used," said study author Silke Kern, MD, PhD with the University of Gothenburg in Sweden. "Recently, however, the use of supplements and their effect on health has been questioned."
The study involved 700 dementia-free women between the ages of 70 and 92 who were followed for five years. Participants took a variety of tests at the beginning and end of the study, including tests of memory and thinking skills. A CT brain scan was performed in 447 participants at the start of the study.
Scientists also looked at the use of calcium supplements in the participants and whether they were diagnosed with dementia over the course of the study. A total of 98 women were taking calcium supplements at the start of the study and 54 women had already experienced a stroke. During the study, 54 more women had strokes, and 59 women developed dementia. Among the women who had CT scans, 71 percent had lesions on their brains' white matter, which is a marker for cerebrovascular disease.
The study found that the women who were treated with calcium supplements were twice as likely to develop dementia than women who did not take supplements. But when the researchers further analyzed the data, they found that the increased risk was only among women with cerebrovascular disease. Women with a history of stroke who took supplements had a nearly seven times increased risk of developing dementia than women with a history of stroke who did not take calcium supplements. Women with white matter lesions who took supplements were three times as likely to develop dementia as women who had white matter lesions and did not take supplements. Women without a history of stroke or women without white matter lesions had no increased risk when taking calcium supplements.
Overall, 14 out of 98 women who took supplements developed dementia, or 14 percent, compared to 45 out of 602 women who did not take supplements, or 8 percent. A total of six out of 15 women with a history of stroke who took supplements developed dementia, compared to 12 out of 93 women with a history of stroke who did not take supplements. Among the women with no history of stroke, 18 out of 83 who took supplements developed dementia, compared to 33 out of the 509 who did not take supplements.
"It is important to note that our study is observational, so we cannot assume that calcium supplements cause dementia," said Kern. The author also noted that the study was small and results cannot be generalized to the overall population, and additional studies are needed to confirm the findings.
Kern noted that calcium from food affects the body differently than calcium from supplements and appears to be safe or even protective against vascular problems.


Provided by American Academy of Neurology

Exercise results in larger brain size and lowered dementia risk

Credit: CC0 Public Domain

Using the landmark Framingham Heart Study to assess how physical activity affects the size of the brain and one's risk for developing dementia, UCLA researchers found an association between low physical activity and a higher risk for dementia in older individuals. This suggests that regular physical activity for older adults could lead to higher brain volumes and a reduced risk for developing dementia.

07 aug 2016--The researchers found that physical activity particularly affected the size of the hippocampus, which is the part of the brain controlling short-term memory. Also, the protective effect of regular physical activity against dementia was strongest in people age 75 and older.
Though some previous studies have found an inverse relationship between levels of physical activity and cognitive decline, dementia and Alzheimer's disease, others have failed to find such an association. The Framingham study was begun in 1948 primarily as a way to trace factors and characteristics leading to cardiovascular disease, but also examining dementia and other physiological conditions. For this study, the UCLA researchers followed an older, community-based cohort from the Framingham study for more than a decade to examine the association between physical activity and the risk for incident dementia and subclinical brain MRI markers of dementia.
The researchers assessed the physical activity indices for both the original Framingham cohort and their offspring who were age 60 and older. They examined the association between physical activity and risk of any form of dementia (regardless of the cause) and Alzheimer's disease for 3,700 participants from both cohorts who were cognitively intact. They also examined the association between physical activity and brain MRI in about 2,000 participants from the offspring cohort.
What this all means: one is never too old to exercise for brain health and to stave off the risk for developing dementia.
The study appears in the Journals of Gerontology Series A: Biological Sciences and Medical Sciences.


Provided by University of California, Los Angeles

Higher dementia risk linked to more use of common drugs

Diagram of the brain of a person with Alzheimer's Disease. Credit: Wikipedia/public domain.

27 jan 2015--A large study links a significantly increased risk for developing dementia, including Alzheimer's disease, to taking commonly used medications with anticholinergic effects at higher doses or for a longer time. Many older people take these medications, which include nonprescription diphenhydramine (Benadryl). JAMA Internal Medicine published the report, called "Cumulative Use of Strong Anticholinergic Medications and Incident Dementia."

The study used more rigorous methods, longer follow-up (more than seven years), and better assessment of medication use via pharmacy records (including substantial nonprescription use) to confirm this previously reported link. It is the first study to show a dose response: linking more risk for developing dementia to higher use of anticholinergic medications. And it is also the first to suggest that dementia risk linked to anticholinergic medications may persist—and may not be reversible even years after people stop taking these drugs.

"Older adults should be aware that many medications—including some available without a prescription, such as over-the-counter sleep aids—have strong anticholinergic effects," said Shelly Gray, PharmD, MS, the first author of the report, which tracks nearly 3,500 Group Health seniors participating in the long-running Adult Changes in Thought (ACT), a joint Group Health-University of Washington (UW) study funded by the National Institute on Aging. "And they should tell theirhealth care providers about all their over-the-counter use," she added.

"But of course, no one should stop taking any therapy without consulting their health care provider," said Dr. Gray, who is a professor, the vice chair of curriculum and instruction, and director of the geriatric pharmacy program at the UW School of Pharmacy. "Health care providers should regularly review their older patients' drug regimens—including over-the-counter medications—to look for chances to use fewer anticholinergic medications at lower doses."

For instance, the most commonly used medications in the study were tricyclic antidepressants like doxepin (Sinequan), first-generation antihistamines like chlorpheniramine (Chlor-Trimeton), and antimuscarinics for bladder control like oxybutynin (Ditropan). The study estimated that people taking at least 10 mg/day of doxepin, 4 mg/day of diphenhydramine, or 5 mg/day of oxybutynin for more than three years would be at greater risk for developing dementia. Dr. Gray said substitutes are available for the first two: a selective serotonin re-uptake inhibitor (SSRI) like citalopram (Celexa) or fluoxitene (Prozac) for depression and a second-generation antihistamine like loratadine (Claritin) for allergies. It's harder to find alternative medications for urinary incontinence, but some behavioral changes can reduce this problem.

"If providers need to prescribe a medication with anticholinergic effects because it is the best therapy for their patient," Dr. Gray said, "they should use the lowest effective dose, monitor the therapy regularly to ensure it's working, and stop the therapy if it's ineffective." Anticholinergic effects happen because some medications block the neurotransmitter called acetylcholine in the brain and body, she explained. That can cause many side effects, including drowsiness, sore throat, retaining urine, and dry mouth and eyes.

"With detailed information on thousands of patients for many years, the ACT study is a living laboratory for exploring risk factors for conditions like dementia," said Dr. Gray's coauthor Eric B. Larson, MD, MPH. "This latest study is a prime example of that work and has important implications for people taking medications—and for those prescribing medications for older patients." Dr. Larson is the ACT principal investigator, vice president for research at Group Health, and executive director of Group Health Research Institute (GHRI). He is also a clinical professor of medicine at the UW School of Medicine and of health services at the UW School of Public Health.

Some ACT participants agree to have their brains autopsied after they die. That will make it possible to follow up this research by examining whether participants who took anticholinergic medications have more Alzheimer's-related pathology in their brains compared to nonusers.

More information: Cumulative Use of Strong Anticholinergic Medications and Incident Dementia, JAMA Internal Medicine, 2015.

Provided by Group Health Research Institute

Diabetes may significantly increase your risk of dementia

People with diabetes appear to be at a significantly increased risk of developing dementia, according to a study published in the September 20, 2011, print issue of Neurology, the medical journal of the American Academy of Neurology.

21 sept 2011--"Our findings emphasize the need to consider diabetes as a potential risk factor for dementia," said study author Yutaka Kiyohara, MD, PhD, of Kyushu University in Fukuoka, Japan. "Diabetes is a common disorder, and the number of people with it has been growing in recent years all over the world. Controlling diabetes is now more important than ever."

People with diabetes were more likely to develop Alzheimer's disease and other types of dementia, such as vascular dementia, which occurs when there is damage to blood vessels that eventually deprive the brain of oxygen.

For the study, a total of 1,017 people who were age 60 and older were given a glucose (sugar) tolerance test after an overnight fast to determine if they had diabetes. Study participants were monitored for an average of 11 years and then tested for dementia. During the study, 232 people developed dementia.

The study found that people with diabetes were twice as likely to develop dementia as people with normal blood sugar levels. Of the 150 people with diabetes, 41 developed dementia, compared to 115 of the 559 people without diabetes who developed dementia.

The results remained the same after the researchers accounted for factors such as high blood pressure, high cholesterol and smoking. The risk of dementia was also higher in people who did not have diabetes, but had impaired glucose tolerance, or were "pre-diabetes."

In addition, the study found the risk of developing dementia significantly increased when blood sugar was still high two hours after a meal.

Provided by American Academy of Neurology

Moderate drinking protects against Alzheimer's and cognitive impairment

Moderate social drinking significantly reduces the risk of dementia and cognitive impairment, according to an analysis of 143 studies by Loyola University Chicago Stritch School of Medicine researchers.

20 aug 2011--Researchers reviewed studies dating to 1977 that included more than 365,000 participants. Moderate drinkers were 23 percent less likely to develop cognitive impairment or Alzheimer's disease and other forms of dementia.

Wine was more beneficial than beer or spirits. But this finding was based on a relatively small number of studies, because most papers did not distinguish among different types of alcohol.

Results are reported in the journal Neuropsychiatric Disease and Treatment. The authors are Edward J. Neafsey, PhD. and Michael A. Collins, PhD., professors in the Department of Molecular Pharmacology and Therapeutics.

Heavy drinking (more than 3 to 5 drinks per day) was associated with a higher risk of cognitive impairment and dementia, but this finding was not statistically significant.

"We don't recommend that nondrinkers start drinking," Neafsey said. "But moderate drinking -- if it is truly moderate -- can be beneficial." Moderate drinking is defined as a maximum of two drinks per day for men and 1 drink per day for women.

Among the studies reviewed, 74 papers calculated the ratios of risk between drinkers and non-drinkers, while 69 papers simply stated whether cognition in drinkers was better, the same or worse than cognition in nondrinkers. Neafsey and Collins did a meta-analysis of the studies that calculated risk ratios and found that moderate drinkers were 23 percent less likely to develop dementia or cognitive decline.

Other findings:

• The protective effect of moderate drinking held up after adjusting for age, education, sex and smoking.
• There was no difference in the effects of alcohol on men and women.
• The beneficial effect of moderate drinking was seen in 14 of 19 countries, including the United States. In 3 of the remaining 5 countries, researchers also found a benefit, but it was not strong enough to be statistically significant.
• The findings were similar across different types of studies (longitudinal cohort studies, case-control studies and cross-sectional studies).

It is unknown why moderate drinking can have a beneficial effect. One theory suggests that the well-known cardiovascular benefits of moderate alcohol consumption, such as raising good HDL cholesterol, also can improve blood flow in the brain and thus brain metabolism.

A second possible explanation involves "sick quitters." According to this theory, nondrinkers have a higher risk of cognitive impairment and dementia because the group includes former heavy drinkers who damaged their brain cells before quitting. But the analysis by Neafsey and Collins did not support this explanation. They found that in studies that excluded former heavy drinkers, the protective effect of moderate drinking still held up.

Neafsey and Collins suggest a third possible explanation: Small amounts of alcohol might, in effect, make brain cells more fit. Alcohol in moderate amounts stresses cells and thus toughens them up to cope with major stresses down the road that could cause dementia.

For people who drink responsibly and in moderation, there's probably no reason to quit. But because of the potential for alcohol to be abused, Neafsey and Collins do not recommend that abstainers begin drinking.

The researchers note that there are other things besides moderate drinking that can reduce the risk of dementia, including exercise, education and a Mediterranean diet high in fruits, vegetables, cereals, beans, nuts and seeds. Even gardening has been shown to reduce the risk of dementia.

Moreover, there are times when people should never drink, including adolescence, pregnancy and before driving, the researchers said.

Provided by Loyola University Health System

Online tool can help seniors quickly determine risk for dementia

15 jan 2011 -- A quick online assessment tool developed by Johns Hopkins researchers can help worried seniors find out if they are at risk of developing dementia and determine whether they should seek a comprehensive, face-to-face diagnosis from a physician, according to a new study.

The tool, which is being refined and validated, is not meant to replace a full evaluation from a doctor that includes a physical exam, blood work, imaging studies and more. Instead, this assessment provides a scientific way to help a person educate herself about a disease that doctors now believe is best managed if caught early.

“As the population ages and dementia becomes more prevalent, it’s important to get people diagnosed early,” says Jason Brandt, Ph.D., a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and the leader of the study appearing online in the journal Alzheimer’s & Dementia. “Alzheimer’s disease and other types of dementia don’t just creep up on you. They’re incubating for decades in the brain. This tool is potentially very useful in determining who is at risk.”

Among the questions asked on the Dementia Risk Assessment are about whether a person has a history of high blood pressure, depression, diabetes, high cholesterol or head injury, all of which are considered well-documented risk factors for dementia. The assessment also includes a simple memory test that could point to a subtle cognitive decline, Brandt says.

The study analyzed responses from 357 people over the age of 50 who took the assessment at alzcast.org. Those who scored lowest on the memory test were significantly older, and were more likely to be men, have hypertension and report severe memory problems. And while only 9 percent of respondents reported they had severe memory problems, more than one-third said they had a first-degree relative with dementia or severe memory loss — a major risk factor for the condition.

The assessment takes just five to 10 minutes to complete online, and the questions have been borrowed from other scientifically valid assessments.

Brandt says the assessment may be helpful in weeding out those who have signs of dementia from those who are simply experiencing the memory loss that comes with aging or a busy lifestyle. Not being able to find your keys or remembering where you parked is rarely a failsafe sign that a person is suffering from dementia.

“Our goal is really to educate people about what some of the risk factors are and, often, to put people’s minds at ease,” he says. “We somehow expect our memories to be as good at 50 as they were at 30. We can’t run as fast as we could 20 years ago. Why should our memory be as good?”

Alzheimer’s disease still has no cure, but early interventions are being used to slow cognitive decline, Brandt says. Brandt says he hopes this assessment will get patients with several risk factors or symptoms to consult a physician.

Some forms of dementia, he says, may not be permanent, and getting to a doctor could help to restore brain function.

Sometimes, Brandt says, seniors are afraid to mention they are having memory or other cognitive issues. The new tool, he says, lets them learn more about themselves and their individualized risk factors in the privacy of their homes.

The aging population means that many more people will be diagnosed with dementia in the coming decades.

“Screening procedures that have demonstrated validity and predictive value and are noninvasive, brief and do not require any special expertise to administer may have the greatest potential to be accepted and actually used by the greatest number of people,” Brandt says. “This tool, which this study preliminarily validates, is the first step toward developing such a procedure.”

Brandt and colleagues are currently conducting research that compares a patient’s results from the online Dementia Risk Assessment with an in-person, comprehensive evaluation by a physician at one of two Johns Hopkins clinics.

More information: http://www.alzcast.org/

Why more education lowers dementia risk

A team of researchers from the UK and Finland has discovered why people who stay in education longer have a lower risk of developing dementia – a question that has puzzled scientists for the past decade.

26 july 2010--Examining the brains of 872 people who had been part of three large ageing studies, and who before their deaths had completed questionnaires about their education, the researchers found that more education makes people better able to cope with changes in the brain associated with dementia.

Over the past decade, studies on dementia have consistently showed that the more time you spend in education, the lower your risk of dementia. For each additional year of education there is an 11% decrease in risk of developing dementia, this study reports.

However, these studies have been unable to determine whether or not education – which is linked to higher socioeconomic status and healthier lifestyles – protects the brain against dementia.

This is not the case, the new study lead by Professor Carol Brayne of the University of Cambridge has found. Instead, the study shows people with different levels of education have similar brain pathology but that those with more education are better able to compensate for the effects of dementia.

According to co-author Dr Hannah Keage of the University of Cambridge: "Previous research has shown that there is not a one-to-one relationship between being diagnosed with dementia during life and changes seen in the brain at death. One person may show lots of pathology in their brain while another shows very little, yet both may have had dementia. Our study shows education in early life appears to enable some people to cope with a lot of changes in their brain before showing dementia symptoms."

Compared with previous research, this study was able to answer the question because of its large size and statistical power.

The researchers used data from the EClipSE collaboration, which combines the three European population-based longitudinal studies of ageing (the Medical Research Council Cognitive Function and Ageing Study, the Cambridge City Over-75s Cohort Study and Vantaa 85+, a Finnish study).

The studies have assessed participants for up to 20 years and are three of only six such studies in the world.

The results have important implications for public health at a time when populations in many countries are ageing.

"Education is known to be good for population health and equity. This study provides strong support for investment in early life factors which should have an impact on society and the whole lifespan. This is hugely relevant to policy decisions about the importance of resource allocation between health and education," says Professor Brayne.

The results are published today in the journal Brain. The study was funded by the BUPA Foundation, the European Union and the Medical Research Council.

ICAD: Reduced Dementia Risk Linked to Alcohol Intake

Eight to 14 drinks weekly associated with nearly 40 percent decreased risk of dementia

15 july 2009-- Moderate alcohol intake reduces the risk of dementia in cognitively normal older adults by almost 40 percent, according to research presented at the 2009 International Conference on Alzheimer's Disease, held July 11 to 16 in Vienna, Austria.

Kaycee M. Sink, M.D., of Wake Forest University School of Medicine in Winston-Salem, N.C., and colleagues evaluated adults without dementia (75 years and older) who were classified as cognitively normal or with mild cognitive impairment at the beginning of the study. Participants self-reported weekly alcohol consumption as none (42.6 percent), 1 to 7 drinks (light, 38.2 percent), 8 to 14 drinks (moderate, 9.4 percent), or more than 14 drinks (heavy, 9.8 percent).

The researchers note that, over a median follow-up of six years, 523 new cases of dementia were diagnosed. For individuals who were cognitively normal at baseline, moderate alcohol intake was linked to a 37 percent decreased risk of dementia after adjusting for several factors, including patient demographics, smoking, comorbidities, depression, social activity, and baseline cognitive function. With any degree of alcohol consumption, participants with baseline mild cognitive impairment experienced more rapid rates of cognitive decline than cognitively normal individuals. Participants with mild cognitive impairment and heavy alcohol consumption had a 1.84-fold increased risk of dementia versus those with mild cognitive impairment and no alcohol consumption.

"Our findings suggest mild to moderate alcohol intake may reduce the risk of dementia," Sink concluded in a statement, adding that this effect did not seem to be true for individuals who already experienced mild cognitive impairment. "Current recommendations not to exceed one drink per day for women and two for men are supported by these results."

Abstract - Page 3
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Study Finds Risk of Dementia Increases After Hypoglycemia

By RONI CARYN RABIN

23 april 2009--People with Type 2 diabetes may be at increased risk for developing dementia as they age, several studies have suggested. Now researchers say the higher odds may be linked to life-threatening drops in blood sugar, or hypoglycemia, usually caused by excess insulin.

A long-term study of thousands of older patients with Type 2 diabetes in Northern California found that those who had experienced even one episode of hypoglycemia serious enough to send them to a hospital were at higher risk for developing dementia than diabetic patients who had not experienced such an episode. With each additional episode, the risk of developing dementia increased, the study found.

The findings, to be published on Wednesday in the Journal of the American Medical Association, are significant given the high rates of Type 2 diabetes around the world, and the expectation that dementia rates will increase as the population ages.

“We’ve known for some time that patients with Type 2 diabetes are at greater risk of dementia and cognitive problems,” said Rachel A. Whitmer of the Division of Research at Kaiser Permanente in Oakland, Calif., one of the authors. “This adds to the evidence that balance of glycemic control is important, and that trying to aim for a very low glycemic target might not be beneficial and might even be harmful.”

The study found that the risk of dementia among patients who had experienced a single episode of hypoglycemia that required hospitalization was 26 percent higher than the risk for patients who had never had an episode.

Patients who had experienced two episodes faced an increased risk of 80 percent, while those who had experienced three episodes or more had a 94 percent increase in risk, or almost double the odds of developing dementia.

“To see an effect after just one episode is remarkable,” said Dr. Alan M. Jacobson, a researcher at the Joslin Diabetes Center in Boston. An earlier study of Type 1 diabetes and dementia found no connection, Dr. Jacobson noted.

Researchers gathered their data from 16,667 Kaiser Permanente patients with Type 2 diabetes. They used hospital data to determine how many had experienced severe hypoglycemic episodes from 1980 to 2002 and how many had first received a diagnosis of dementia from 2003 to 2007, when their mean age was 74 to 78.

Hypoglycemic Events Increase Dementia Risk with Diabetes

Risk increases with the number of hypoglycemic events, nearly doubling for three or more

16 april 2009-- Incidents of hypoglycemia in older patients with type 2 diabetes increase the risk of their eventually developing dementia, according to a study in the April 15 issue of the Journal of the American Medical Association.

Rachel A. Whitmer, Ph.D., of Kaiser Permanente in Oakland, Calif., and colleagues conducted a longitudinal study of 16,667 patients (mean age of 65 years) with type 2 diabetes. Hypoglycemic events that occurred from 1980 to 2002 were identified from hospital and emergency department records, and then followed up until 2007 to determine whether dementia diagnoses developed. From these data, the risk of developing dementia was calculated using Cox proportional hazard regression models.

The investigators found that dementia was eventually diagnosed in 1,822 patients, among whom 250 had had at least one hypoglycemia incident. Compared to patients with no hypoglycemia incidents, the group had an elevated risk of dementia that increased with the number of episodes. The adjusted hazard ratios were 1.26 for one hypoglycemic incident, 1.80 for two incidents, and 1.94 for three or more incidents. The risk of dementia attributable to hypoglycemic incidents was 2.39 percent per year, the researchers report.

"Among older patients with type 2 diabetes, a history of severe hypoglycemic episodes was associated with a greater risk of dementia. Whether minor hypoglycemic episodes increase risk of dementia is unknown," the authors write.

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Low blood sugar a dementia risk for diabetics

By Julie Steenhuysen
CHICAGO, 15 april 2009 - Older diabetics whose blood sugar drops to dangerously low levels have a higher risk of developing dementia, U.S. researchers said on Tuesday.

The study by researchers at Kaiser Permanente in Oakland, California, suggests that aggressive blood sugar control resulting in blood sugar so low it requires a trip to the hospital may increase dementia risks in older adults with type 2 diabetes.

"We know that having blood sugar that is too high is not good," Rachel Whitmer, a Kaiser research scientist whose study appears in the Journal of the American Medical Association, said in a telephone interview.

"You want to keep that blood sugar at a good level, but you don't want to go too low," she said.

Several studies have found that diabetics have a higher risk of developing Alzheimer's disease -- the most common form of dementia -- than do the general population. And others have shown that diabetics who take insulin and pills to help control their disease have a lower Alzheimer's risk.

"The very current issue here is balance of blood sugar control," Whitmer said.

She said a number of things such as a missed meal can cause severe low blood sugar in diabetics, but the chief cause is too much insulin, which can happen in people who take insulin injections or with oral diabetes drugs such as sulfanylureas or glimepiride that cause the body to make more insulin.

She and colleagues looked at more that two decades of data in more than 16,600 patients with type 2 diabetes.

The team checked to see if prior episodes of low blood sugar that were severe enough to require a trip to the hospital were associated with a higher risk of dementia.

They found that compared with people who had no severe bouts of low blood sugar, diabetics with single or multiple episodes had higher dementia risks, and risk levels rose depending on the number of severe hypoglycemic episodes.

"In older patients with a history of one episode, they had a 26 percent greater risk of dementia. Patients with two episodes had a 115 percent greater risk of dementia. And patients with three or more episodes had a 160 percent greater risk of dementia," Whitmer said.

She said the study offers more evidence that aggressive measures to control blood sugar can cause harm in elderly diabetics.

It follows three recent trials that found tight glycemic control could cause heart disease and death in some elderly diabetics.

She and colleagues plan to look at dementia risks for people in the study who took glitazones -- a class of drugs that help diabetics use insulin better. Drugs in this class include GlaxoSmithKline's Avandia or rosiglitazone and Takeda Pharmaceutical's Actos or pioglitazone.

Alzheimer's is the most common form of dementia among older people, affecting 5.2 million people in the United States, according to the Alzheimer's Association. Some 23.6 million Americans have diabetes, according to the American Diabetes Association.

Personality and dementia risk

Keeping active, both mentally and physically, reduces dementia risk

26 jan 2009--“Being laid-back and outgoing makes you 50% less likely to develop Alzheimer's disease”, the Daily Mail reported. The newspaper said that people who are anxious, shy and prone to stress are more likely to go on to develop dementia. It said a study looked at the personalities and lifestyles of 506 older people and followed them for six years. Those who were calm had a 50% lower risk of dementia, even if they were not socially active, than those who were isolated and prone to stress.

This study found that people with low levels of neuroticism and high levels of extroversion (calm, relaxed types with outgoing personalities) had less risk of dementia than those with high neuroticism (those prone to distress and poor coping responses) and high extroversion.

However, the study cannot prove that these personality factors themselves affected the risk of dementia, as early dementia-related changes could themselves have affected personality. This study has not looked at whether changing your personality, which may not be possible, can affect your risk of dementia. For elderly people, maintaining social contact with others is likely to have benefits, but whether or not it reduces dementia risk remains to be proven.

Where did the story come from?

Dr Hui-Xin Wang and colleagues from the Karolinska Institutet and other research institutes in Sweden and the US carried out this research. The work was funded by the Swedish Council for Working Life and Social Research, and various other charitable organisations in Sweden and the US. The study was published in the peer-reviewed medical journal: Neurology.

What kind of scientific study was this?

This prospective cohort study looked at the relationship between personality traits (neuroticism and extroversion), lifestyle and dementia. Previous studies have found that stress is associated with degenerative changes in the brain. It has also been found that people’s personality traits and their level of social interaction may affect their ability to cope with stress. Therefore, the researchers wanted to investigate whether these factors might affect risk of dementia, which is a result of degenerative changes in the brain.

The participants were obtained from a previous cohort study of ageing and dementia in Sweden. The researchers excluded anyone from that study who met criteria for probable dementia at the time of assessment, and those who were unable to complete a personality questionnaire that assessed neuroticism and extroversion. This neuroticism part of the questionnaire is designed to identify people prone to ‘psychological distress, unrealistic ideas, excessive cravings or urges, and maladaptive coping responses’. Low scores indicate people to be ‘calmer, more relaxed, unemotional, and self-satisfied’. The extroversion part of the questionnaire assesses ‘quantity and intensity of interpersonal interaction, activity level, need for stimulation, and capacity for joy’. People who score lower on extraversion are identified as being ‘more reserved, sober, task-oriented, and quiet’.
Those who met inclusion criteria were asked to take part in a personal interview in which they were asked about their lifestyle, including their social interactions and leisure activities.

Of the people who were asked, 544 completed the questionnaire, and 506 (average age 83 years) were successfully followed up for an average of six years. The participants were given a full clinical assessment at three and six years, including medical history and psychological assessment. If an individual could not answer questions, the researchers identified a person close to them who could provide the relevant information.

Diagnoses of dementia were based on standard criteria. Two physicians made independent diagnoses, and if they agreed then this was the final diagnosis. If they disagreed then a third opinion was obtained. If a person died, their medical history and diagnoses were assessed using hospital records and death certificates.

The researchers then looked at whether levels of neuroticism or extroversion were individually associated with dementia. They also looked at the effects of these two personality traits together, and at how this association was affected by social interaction. They compared the proportion of people who developed dementia among those with low levels of neuroticism, extroversion or both with those who had high levels of both. The researchers adjusted their analyses for factors that could affect the results, such as whether the participants had the form of the ApoE gene which has been associated with a higher risk of Alzheimer’s disease. They also took into account the participants’ age, cognitive function, gender, level of education, depressive symptoms or diagnoses, vascular disease, and whether they had died or were still alive at follow up.

What were the results of the study?

Of the 506 participants, 144 (28%) developed dementia during the six years of follow up. When they looked at each personality trait individually, the researchers found no association between the participants’ neuroticism or extroversion and their risk of developing dementia. However, when the two traits were assessed together some associations with dementia were found. People who had low neuroticism but high extroversion were about half as likely to develop dementia as those with high neuroticism and high extroversion (hazard ratio 0.51, 95% CI 0.28 to 0.94). Risk of dementia among people with low neuroticism and extroversion, or high neuroticism and low extroversion did not differ from those with high levels of both traits.

The researchers then split the participants into those with different social lifestyles. Among those who had an inactive and socially isolated lifestyle, people who were less neurotic had a lower risk of dementia than those who were more neurotic, but this was not the case among people with an active and socially integrated lifestyle. Extroversion was not associated with risk of dementia in either socially inactive or socially integrated groups.

What interpretations did the researchers draw from these results?

The researchers concluded that people with low neuroticism and high extroversion have the lowest risk of dementia. They say that low neuroticism alone can reduce the risk of dementia in people with an inactive and socially isolated lifestyle.

What does the NHS Knowledge Service make of this study?

The prospective design of this study is one of its strengths; however, there are some limitations to consider:

• Even though this study followed people over time, it is difficult to determine the sequence of events. People who did not have detectable dementia may have had very early brain changes associated with this condition, and these changes may have affected their personality rather than the other way around. However, the authors feel they reduced this possibility by testing for cognitive performance at the beginning of the study, and adjusting their analyses accordingly.
• Even if the personality traits preceded the brain changes, it does not necessarily mean that the personality traits themselves increased the risk of dementia. There may be another factor or factors that affect both personality and risk of dementia.
• About a third of the people asked did not complete the personality questionnaire, and this may have affected the results if they differed from those who chose to complete it.
• Personality was only assessed once, and may not have been indicative of personality at other times during the participants’ lives.
• It is not possible to say from this study whether attempting to change one’s social life would have an effect on risk of dementia.
• The results may not be applicable to other countries, where social customs and interactions may differ.

Further replication of the findings of this study in other settings would increase confidence in the results. By objectively measuring dementia over time, by using a series of brain scans for example, it may be possible to avoid the criticism that this study is a “chicken and egg scenario”. These could help to determine whether it is the personality traits that increase the risk of dementia or if they are simply an early sign of the disease.

Belly Fat May Pose Dementia Risk

By Charles Bankhead
OAKLAND, Calif., March 26 -- A middle-age paunch may heighten the risk of older-age dementia, according to an analysis of almost 6,600 patients followed for more than three decades.Those with the greatest central fat accumulation had almost a three-fold higher rate of dementia at follow-up compared with patients who had the least amount of central adiposity, Rachel Whitmer, Ph.D., of Kaiser Permanente of Northern California, and colleagues reported in the April issue of Neurology.Central adiposity posed a dementia threat even in patients who had a normal body mass index."These results contribute to a recent but growing body of evidence that a centralized distribution of adiposity is particularly dangerous, even for those who are not overweight, and that the brain may also be a target organ to the harmful effects of central obesity," the authors concluded. "If these results are replicated, our findings imply that central obesity may contribute to degree of cognitive aging."

Central obesity is an independent predictor of diabetes, insulin resistance, coronary heart disease, stroke, and mortality, and has a greater impact on morbidity and mortality compared with total body obesity, the authors pointed out. The increased risk conferred by central obesity may lie in the heightened metabolic activity of visceral fat, which appears to give rise to tissue-toxic adipocytokines and fuel insulin resistance.
Recent population-based studies have suggested that obesity is a risk for cognitive impairment. Whether the pattern of fat distribution influences dementia risk had not been examined.
Dr. Whitmer and colleagues analyzed data on 6,583 Kaiser-Permanente members whose sagittal abdominal diameter was measured during 1964 to 1973, when the patients were ages 40 to 45. Dementia diagnoses were abstracted from medical records an average of 36 years after the assessment of abdominal fat volume.
Medical records showed that 1,049 (15.9%) participants had dementia diagnoses. After stratification by sagittal abdominal diameter, those in the top quintile of visceral fat accumulation had a 2.72 relative risk of dementia compared with patients in the bottom quintile (95% CI 2.33 to 3.33).
There was a dose-dependent increase in the risk of dementia from visceral adiposity. Compared with those in the bottom quintile of sagittal abdominal diameter, the risk of dementia was 20% greater in the second quintile, 49% greater in the third, and 67% greater in the fourth.
After accounting for BMI in the statistical model, the authors found that people with the greatest sagittal abdominal diameter had a two-fold increased risk of dementia compared with those in the lowest quintile (HR 1.92, 95% CI 1.58 to 2.35).
People with sagittal abdominal diameter ≥25 cm and a normal BMI had double the dementia risk of those with less abdominal fat and normal BMI (HR 1.89, 95% CI 0.98 to 3.81). The combination of obesity (BMI>30) and sagittal abdominal diameter ≥25 cm had a dementia risk that was 3.6 times greater than that of individuals with neither anthropomorphic characteristic (95% CI 2.85 to 4.55).
The results were unchanged in separate analyses of different types of dementia.
The authors noted several limitations to the study.
"No information on dieting, nutrition, or cognitive function was collected although obese persons have different nutritional and exercise habits than non-obese persons."
"Due to body composition imaging technology (CT or MRI) not being available in the 1960s we were not able to directly distinguish the effects of visceral versus subcutaneous adiposity."
"Our study only included those who were still alive in 1994, the onset of dementia ascertainment, therefore we only could examine the association between central obesity and dementia among those who made it to old age."
The authors had no disclosures.
Primary source: NeurologySource reference:Whitmer RA, et al "Central obesity and increased risk of dementia more than three decades later" Neurology 2008; epub.

Dietary Factors May Influence Dementia Risk

BORDEAUX, France, Nov. 13 -- A diet rich in fruits, vegetables, fish, and omega-3 fish oil may afford protection against dementia, investigators here concluded.
Action Points
Explain to interested patients that regular consumption of fruits, vegetables, and fish may reduce the risk of Alzheimer's disease and dementia.
Note that some of the benefit appears to be limited to people who have a particular lipid-related genotype.
Older individuals who reported daily consumption of fruits and vegetables had almost a 30% lower risk of dementia compared with people who reported less frequent consumption, Pascale Barberger-Gateau, Ph.D., of University Victor Segalen, and colleagues, reported in the November issue of Neurology.
Weekly fish consumption reduced the risk of Alzheimer's disease and all-cause dementia, but only in ApoE ε4 noncarriers, the researchers found. Regular intake of omega-3 fish oils also reduced the risk of dementia, whereas omega-6 consumption that was not balanced by omega-3 or fish increased the risk of dementia in ApoE ε4 noncarriers.
The results add to previous evidence of dietary associations with dementia risk, but the authors emphasized that the evidence falls short of definitive proof.
"More research is needed to identify the optimal quantity and combination of nutrients that could be protective before implementing nutritional recommendations," they concluded.
Interest in modifiable risk factors for Alzheimer's disease and other forms of dementia has led to several examinations of dietary factors, in particular fat and antioxidants. In the PAQUID French cohort study of older adults, regular fish consumption was associated with a significantly decreased risk of dementia during seven years of follow-up (BMJ 2002; 325: 932-933). Several other studies have demonstrated similar associations, the authors noted.
The protective effect of fish consumption has been attributed to high concentrations of omega-3 fatty acids, which are major components of neuron membranes and have vascular and anti-inflammatory effects, they continued. However, epidemiologic studies have yielded inconsistent results on the association of fish and omega-3 fatty acid consumption with dementia. Moreover, demographic, socioeconomic, and other dietary factors could confound the association.
So Dr. Barberger-Gateau and colleagues examined various components of a diet rich in fat or antioxidants and associations with dementia, adjusting for individual characteristics and potential interactions between foods and ApoE genotype.
The study population comprised 8,085 adults without dementia ages 65 and older in the Three City cohort study, an ongoing evaluation of vascular risk factors and dementia.
The participants were enrolled during 1999 and 2000, and each had at least one clinic visit during four years of follow-up. An independent committee of neurologists confirmed 281 cases of dementia during the follow-up period.
The analysis showed that daily consumption of fruits and vegetables significantly decreased the risk of all-cause dementia, as reflected by an adjusted hazard ratio of 0.72.
Weekly fish consumption reduced the risk of Alzheimer's disease by 35% (HR: 0.65, 95% CI: 0.43 to 0.994).
Regular fish consumption also reduced the risk of all-cause dementia by 40% (HR: 0.60, 95% CI: 0.40 to 0.90), but only in study participants who were ApoE ε4 noncarriers.
Regular consumption of omega-3 fatty acids was associated with a nonsignificant 54% reduction in the hazard ratio for all-cause dementia.
A diet rich in omega-6 oils doubled the risk of dementia in ApoE ε4 noncarriers in the absence of compensatory consumption of omega-3 oils or fish (HR: 2.12, 95% CI: 1.30 to 3.46).
"Given that most individuals are ApoE ε4 noncarriers, these findings could have considerable implications in terms of public health," the authors concluded.
The authors reported no conflicts of interest.Primary source: NeurologySource reference: Barberger-Gateau P, et al "Dietary patterns and risk of dementia. The Three-City Cohort Study"Neurology 2007; 69: 1921-1930.

Low Education Level Independently Increases Dementia Risk

Caroline Cassels

October 1, 2007 — Low levels of education appear to independently increase dementia risk regardless of other potential contributors, including demographic, socioeconomic, and vascular factors, new research suggests.
Results from the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study showed that, compared with individuals with the lowest levels of education, highly educated individuals had an 80% lower dementia risk.
"Generally speaking, people with low education levels seem to lead unhealthier lifestyles, which could suggest the 2 work concurrently to contribute to dementia or Alzheimer's disease, but our results showed a person's education predicted dementia on its own," said Tiia Ngandu, MD, PhD, of the Karolinska Institute in Stockholm, Sweden.
It might be that highly educated people have a greater cognitive reserve, which is the brain's ability to maintain function in spite of damage, making it easier to postpone the negative effects of dementia. Additionally, unhealthy lifestyles may independently contribute to the depletion of this reserve," Dr. Ngandu added.
The study is published in the October 2 issue of Neurology.
Methods
Derived from 4 separate independent population-based, randomly selected samples (from 1972, 1977, 1982, and 1987), the CAIDE study followed 1388 individuals from middle age to late life (an average of 21 years); they underwent re-examination in 1998.
During the mid-life examination, study participants filled out a self-administered questionnaire covering socioeconomic factors, health behavior, health status, and medical history. In addition, a venous blood sample was taken and systolic and diastolic blood pressure and height and weight were measured.
Information on education level was also gathered at the mid-life examination. Study subjects were categorized into 3 groups: those with 5 years of education or less (low); those with 6 to 8 years of education (medium); and those with 9 or more years of education (high).
Methods for the late-life examination were the same as those used in the mid-life exam. During this phase of the study, participants underwent ApoE genotyping and had their cognitive status assessed. Study subjects who scored 24 or less on the Mini-Mental State Examination (MMSE) were referred for further diagnostic examination.
A total of 61 individuals met the diagnosis of dementia. Of these, 48 had Alzheimer's disease.
Dose-Dependent Effect
"Education was associated with the risk of dementia in a dose-dependent manner. Compared with people with low education, those with medium education had a 40% lower risk of developing dementia, and those with high education had 80% lower risk for dementia," the authors write.
According to the investigators, adjustment for potential confounders/mediators, including demographic, socioeconomic, and vascular factors, as well as mid-life physical activity levels, ApoE status, and depression, did not change the results.
"Our study showed that Finnish people with medium to high education have a lower risk of dementia when compared with persons with a low education level. The confounding/mediating effects related to differences in socioeconomic, vascular, or lifestyle characteristics between people with different levels of education were taken into account. However, none of these factors changed the results, suggesting that the effect of education is independent of other risk factors for dementia," they write.
Investigators found that those in late life those with lower education at midlife had a higher occurrence of dementia and Alzheimer's disease.
The study was funded by the Alzheimer's Association, the Aging Program of the Academy of Finland, and Kuopio University Hospital in Finland.
Neurology. 2007; 69:1442-1450.

Heavy elderly not at risk of memory decline

Mon Sep 24, 11:41 AM ET
Older adults who are overweight do not seem to be at any extra risk of memory decline, a new study suggests.
In fact, researchers found, it was underweight men and women who were more likely to see their memory suffer over time. They speculate that this is because poor nutrition and weight loss may be early manifestations of Alzheimer's disease in some older people.
The findings, reported in the journal Neurology, stand in contrast to research that has linked obesity in middle-age to a greater risk of dementia later in life.
It's thought that obesity in mid-life may raise dementia risk indirectly, by leading to health problems that impair blood flow to the brain, like high blood pressure and diabetes. Experts also theorize that excess fat cells have some direct effect on brain function.
However, in old age, being overweight or obese may not be a liability when it comes to mental function, according to the authors of the new study.
"We do not know yet why being overweight or obese does not increase the risk for cognitive decline in old age," lead study author Dr. Maureen T. Sturman, of Rush University Medical Center in Chicago, said in a statement.
"However being underweight may be a correlate of the initial stages of Alzheimer's disease," she added.
The findings are based on 3,885 adults age 65 and older who took standard tests of memory and other mental functions at the start of the study, then twice more over the next six years.
Sturman's team found no relationship between obesity and the risk of memory changes or other signs of mental decline over time. In contrast, study participants who were underweight at the outset were at heightened risk of decline.
"While past studies have found obesity in middle age increases a person's risk for dementia or Alzheimer's disease, our findings show obesity in old age has no effect on a person's memory," Sturman said.
Studies should continue to look at the effect of weight on older adults' mental functioning so that firmer lifestyle advice can be given, Sturman and her colleagues conclude. Older people may do better to focus on healthy eating, physical activity and mental "exercise" -- like reading and doing crossword puzzles -- than on shedding excess weight, they suggest.
SOURCE: Neurology, online September 19, 2007.

VAS-COG: Poor Dental Health May Raise Risk of Dementia

SAN ANTONIO, July 13 -- The fewer teeth someone has in middle age, the greater the risk seems to be for dementia later in life, data from an ongoing study of women's health suggest.
Poor dental health increased the likelihood of dementia by 30% to 40% over a 32-year period, regardless of cardiovascular status, according to a report at the International Society of Vascular Behavioral and Cognitive Disorders meeting here.
After adjustment for multiple demographic and clinical factors, the association between tooth count and dementia remained significant.
Previous studies have suggested an association between poor dental health and cardiovascular disease, possibly linked by the common thread of lower socioeconomic status. However, the two seemingly disparate health conditions also have some intriguing potential biological links, said Robert Stewart, M.D., of King's College London, England.
"Inflammation is a particularly interesting area," Dr. Stewart said. "Someone with poor dental health often has chronic infections in their teeth and gums. This gives rise to circulating inflammatory markers, and circulating inflammatory markers are potentially related to cardiovascular disease, dementia, and a host of other diseases that people are very interested in studying whether inflammatory pathways are involved."
To look at a dental health/dementia correlation, Dr. Stewart and colleagues analyzed data from the Women's Health Study of Goteborg, Sweden. The study includes women born in 1908, 1914, 1918, 1922, and 1930. The women had clinical examinations in 1968, 1974, 1980, 1992, and 2000. Dental exams took place in 1968, 1980, and 1992, and diagnostic evaluations for dementia were conducted in 2000.
Dr. Stewart and colleagues conducted a nested analysis of 638 surviving women who had dental exams in 1968 and dementia evaluations. The study group included 84 women who met criteria for dementia.
As compared with dementia-free participants, women with dementia were older (more than 90% were 78 or older), were less likely to have a high school education, and more likely to have a history of myocardial infarction.
Comparison of dental status and prevalence of dementia revealed a clear inverse association between tooth count and dementia in 1968, 1980, and 1992 (years when dental exams occurred). For example, about 25% of women with dementia had fewer than nine teeth at the 1968 dental exam, compared with a dementia prevalence of about 5% in women who had 25 or more teeth.
In an analysis adjusted only for age, declining tooth count was associated with an odds ratio of 1.3 for dementia. Adjustment for education and a variety of cardiovascular risk factors had minimal impact on the association. Adjustment for weight change between 1968 and 1992 resulted in an odds ratio of 1.4.
"Dental health is a prospective predictor of dementia which does not appear to be accounted for by cardiovascular comorbidity," Dr. Stewart concluded. "It may in part be a marker of cognitive reserve or education but inflammatory and nutritional causal pathways require investigation."
Future investigations will focus on finding other cohorts with data from dental and cognitive assessments, he added, but very few have been identified thus far.
None of the investigators had financial disclosures related to the study.Primary source: International Society of Vascular Behavioral and Cognitive DisordersSource reference: R Stewart et al. "Dental health, vascular status, and risk of dementia: the Goteborg women's health study. International Society of Vascular Behavioral and Cognitive Disorders meeting, July 11-14, San Antonio. Final Program. Abstract P-8.

Eye exam may spot dementia risk in elderly

By David DouglasFri Examining the blood vessels in the retina of the eye may give a clue to the mental status of elderly people and their risk of developing dementia, researchers report.
The presence of retinal damage, or retinopathy, "is a marker of early damage to the blood vessels in the brain, and is a harbinger of future stroke risk," senior investigator Dr. Tien Yin Wong of the University of Melbourne Centre for Eye Research, Australia, told Reuters Health.
In order to see if retinopathy might also be linked to cognitive function and dementia, Wong and colleagues studied retinal photographs of 2211 people aged 69 to 97 years. More than half of them had hypertension, i.e., high blood pressure.
After adjusting for factors such as age, diabetes, and smoking status, subjects with retinopathy had lower scores on a standard test of cognitive status than those without (39 versus 41), the team reports in the medical journal Stroke
In subjects with high blood pressure, retinopathy doubled the likelihood of having dementia. No such relationship was seen in those without high blood pressure.
The investigators concluded that there is a "modest cross-sectional association between retinopathy signs and poorer cognitive function and, in persons with hypertension, with dementia."
SOURCE: Stroke, July 2007.