Scientists Cant Say For Sure Whether Family History Predicts Alzheimers Or Not
There is one rare type of Alzheimers disease, called early-onset familial Alzheimers disease , that is known to be genetic and will appear throughout a family tree. However, this accounts for only 5 percent of all Alzheimers cases.
For the rest, Alzheimers research is not conclusive. Some studies indicate that people with a parent or sibling who has Alzheimers have a slightly higher risk of developing it themselves. But experts hesitate to say for sure whether youre considerably more likely to develop Alzheimers if a family member has it.
Patrick Lyden, MD, neurology professor at Cedars-Sinai in Los Angeles, told The Mighty this idea has gotten into the public mindset likely due to news reports about the rare family-inherited dementias, but there isnt a definite one-to-one risk for Alzheimers. In fact, this is one of the most common misconceptions he encounters.
If you have one parent with Alzheimers and youre worried about your own risk, thats where we really dont know, Lyden said. In some cases those are hereditary, but a lot of times when youre talking about something thats so common, it might just be a coincidence.
Genetic Testing Not Helpful
When a relative is diagnosed with dementia later in life, family members often wonder if they should be tested for the “Alzheimer’s gene.” The short answer is no. “It can be a quick no or a long no, with more explanation, but the answer is nearly always no,” Dr. Marshall says. “It’s not going to be helpful, since it won’t tell you whether you will develop the disease. It will only tell you if you are at a greater or lower risk.”
For Alzheimer’s disease that begins later in lifethe vast majority of casesa gene called apolipoprotein E is associated with greater risk for dementia. If you inherit one copy of APOE4, your risk triples. If you have two copies, your risk is 10 to 15 times higher .
But having APOE4 does not mean you will definitely develop dementia. Among people who age normally into their 70s, about 25% still have one or more copies of the risk gene. Nor does the absence of APOE4 protect you: about 35% of people with Alzheimer’s don’t have one of the risk genes.
This means that if genetic testing reveals that you have one or more copies of APOE4, it will not tell you what you really want to know: will you definitely get Alzheimer’s diseaseor will you not? Knowing that you have the risk gene could instill fear and negatively influence your life decisions.
Am I At Risk For Alzheimer’s
Whether we have seen early signs in ourselves or not, many of us want to know what our chances of getting this disease may be. Research has shown a number of possible factors that can impact your chances of getting Alzheimer’s disease, although none of these are a cause in and of themselves.
Some ages are more at risk
Old age is one of the most obvious risk factors. The vast majority of people develop the disease after the age of 65, and once you reach 65, your risk of getting Alzheimer’s doubles every five years. But Alzheimer’s doesn’t only affect people over 65 it has been known to affect people half that age, although this is much rarer.
Alzheimer’s is hereditary
A family history will also increase your risk of getting the disease. The risk increases even more if you have multiple family members who have suffered from the disease.
Whilst this may be due to the hereditary genetic factors we will look at in more depth later, there may be other factors at play. These could include environmental factors that impact both yourself and your family.
Gender is another significant risk factor. The first discovery of the disease back in 1906 was in a woman, and about twice as many women as men over 65 have Alzheimer’s. This may be in part to the fact that women have a longer lifespan or may even possibly be linked to menopause.
Genetic factors of Alzheimer’s
Other risk factors
Don’t Miss: Alzheimers Ribbon Color
Mom Has Alzheimer’s Your Risk May Be High
Study Suggests Risk for Alzheimer’s May Be Higher if You Have a Mom With Late-Onset Alzheimer’s
In the study, the children of mothers with late-onset Alzheimer’s disease showed stronger evidence of Alzheimer’s-like changes in the brain, as reflected on positron emission tomography imaging.
“People think that if they reach middle age and don’t have memory issues, they’re not going to be affected,” says study researcher Megan Cummings, research coordinator for New York University’s Center for Brain Health in New York City. “That’s not necessarily true.”
“If the findings are confirmed in larger studies, cognitively normal adults of mothers — or even fathers — with late-onset Alzheimer’s disease might benefit from early intervention,” she tells WebMD.
For now, early intervention might involve more frequent testing for dementia, but in the future, there may be drugs that slow or stop the progression from preclinical Alzheimer’s disease to full-blown Alzheimer’s. Preclinical Alzheimer’s disease is used to describe people with signs of Alzheimer’s in their brains, despite appearing cognitively normal.
Mothers Fathers And Alzheimers Disease
Having a parent with Alzheimers disease increases your risk of developing the disease yourself. But people whose mothers had Alzheimers are more likely to get the disease than those whose fathers had it.
Those are the results of a new study that looked at the brains of healthy people, some of whose parents had Alzheimers. The findings are consistent with earlier research showing that the chances of inheriting the disease from your mother are greater than from your father.
It is estimated that people who have first-degree relatives with Alzheimers disease are four to 10 times more likely to develop the disease themselves compared to people with no family history, said study author Robyn Honea of the University of Kansas School of Medicine in Kansas City. The findings were published in Neurology, the medical journal of the American Academy of Neurology.
For the study, researchers enlisted the help of 53 mentally alert men and women over age 60. Eleven had a mother with Alzheimers, 10 had a father with the disease, and the remainder said they had no family history of the illness.
Each study volunteer underwent a brain M.R.I. scan at the start of the study, then another scan two years later. Although all remained free of serious memory loss and other symptoms of Alzheimers, those whose mother had Alzheimers had more brain changes typical of Alzheimers disease.
The authors call for more research into the inherited aspects of Alzheimers disease.
Finding Out Your Genetic Or Hereditary Risk May Not Ultimately Affect You
Because risk factors like blood pressure and diet are more influential than genetics , you might ultimately decide that you dont really need to know your genetic or hereditary risk. Anyone, whether they have a family member with Alzheimers disease or not, can benefit from working to lower their risk.
A lot of my patients decide against . Because what are you going to do? Youre going to do diet and exercise, Lyden said. So if youre going to do diet and exercise anyway, why bother finding out that you have this gene.
If you just found out a relative has been diagnosed with Alzheimers disease, try not to jump to the conclusion that you will 100% get it, too. Science does not indicate you need to assume your diagnosis is coming. For the best chance of lowering your risk of Alzheimers, focus on maintaining a healthy lifestyle. And if you have a loved one with Alzheimers and are looking for support, check out these articles written by people who have been there:
There Are Other Risk Factors That Are More Significant Than Genetics
While genetics and hereditary factors may or may not contribute much risk, other factors have been shown to lower your chance of developing Alzheimers. These include: controlled cholesterol and blood pressure, avoiding type 2 diabetes by maintaining your ideal body weight, and exercise. Socialization is another important risk factor mouse studies have found that even for mice that are bred to get Alzheimers, being housed with company led to the mice developing Alzheimers later in their lives. Human studies have also found that loneliness increases Alzheimers risk.
Anybody who has a thought or its crossed their mind about dementia risk, get with the exercise program, get with the Mediterranean diet, get with the weight loss, Lyden said. Youll do more for yourself in that respect than all the genetic tests in the world.
Recommended Reading: Dementia Awareness Color
How Does Peanut Butter Detect Alzheimers
The researchers discovered that those who had an impaired sense of smell in the left nostril had early-stage Alzheimers. They noted that the participants needed to be an average of 10 centimeters closer to the peanut butter container in order to smell it from their left nostril compared to their right nostril.
Dementia Affects The Person Diagnosed But Also Raises Fears For Siblings And Children Here Are The Facts
After a diagnosis of Alzheimer’s disease, families face fears and difficult medical decisions.
Alzheimer’s disease represents a personal health crisis, but it’s also a family concern. What does it mean for your children or siblings if you are diagnosed with Alzheimer’s? What does it mean for you if a close relative develops the condition?
“People think that if their dad or aunt or uncle had Alzheimer’s disease, they are doomed. But, no, that’s not true,” says Dr. Gad Marshall, assistant professor of neurology at Harvard Medical School. “Even though family history adds to the overall risk, age still usually trumps it quite a bit. It means your risk is higher, but it’s not that much higher, if you consider the absolute numbers.”
Recommended Reading: Difference Between Dementia And Senility
More Useful Links And Resources
Risk factors.Alzheimer Society of Canada, 2021. Read about risk factors for dementia in our downloadable, print-friendly infosheet. This sheet also contains strategies and lifestyle changes that can help you reduce your risk of developing dementia.
Understanding genetics and Alzheimer’s disease.Alzheimer Society of Canada, 2018.In our downloadable, print-friendly infosheet, learn more about the role that genetics plays as a risk factor for dementia, and find out whether you should pursue genetic testing.
Risk factors and prevention. Alzheimer’s Society UK. This comprehensive webpage from the Alzheimer’s Society UK has some helpful nuggets of research and advice related to reducing your risk of dementia.
Tobacco use and dementia. World Health Organization , 2014. This report from the WHO details the evidence behind smoking tobacco as a risk factor for dementia.
Women and Dementia: Understanding sex/gender differences in the brain. brainXchange, 2018. This webinar discusses understandings of sex and gender, sex differences in Alzheimerâs disease, how the higher number of women with Alzheimer’s may be due to both, and a discussion of the role of estrogen in the health of brain regions associated with Alzheimerâs disease. In partnership with the Alzheimer Society of Canada and the Canadian Consortium of Neurodegeneration in Aging .
Maternal History Of Alzheimer’s
The results showed a substantial reduction in glucose metabolism in the maternal history group, compared with both the paternal and the no-history groups.
Also, there was a substantial increase in the amount of plaque present in the maternal group, compared with both the paternal and the no-history groups.
“When we looked at both scans together, we found a significant correlation between the area of the brain where the plaque was and where there was a slowing of glucose metabolism,” Cumming says.
While the researchers tried to take into account whether study participants had other risk factors for Alzheimer’s, “they couldn’t control for everything” that could explain the apparent link, she says, citing diabetes and heart disease as examples.
One question that the study presents, Carrillo and Cummings agree, is whether the tendency to develop dementia is somehow being passed on through mitochondrial DNA, which is only inherited from the mother.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.
Don’t Miss: Multi Infarct Dementia Treatment
What Is Alzheimer’s Disease
Alzheimer’s disease is an irreversible brain disorder. It is a progressive condition that causes issues with memory, cognition, and behavior.
It was first discovered in 1906 by Dr. Alois Alzheimer, a German psychiatrist and neuropathologist. He examined the brain of a woman who had died following symptoms including memory loss, language problems, and altered behavior. He found unusual clumps in her brain, known as amyloid plaques, as well as tangles in her brain fibers that are some of the main features of Alzheimer’s disease.
Since this initial discovery, many other complex changes in the brain have been discovered among people suffering from disease, including the loss of connection between neurons.
What Do We Know About Reducing Risk For Dementia
The number of older Americans is rising, so the number of people with dementia is predicted to increase. However, some studies have shown that incidence rates of dementia meaning new cases in a population over a certain period of time have decreased in some locations, including in the United States. Based on observational studies, factors such as healthy lifestyle behaviors and higher levels of education may be contributing to such a decline. But the cause and effect is uncertain, and such factors need to be tested in a clinical trial to prove whether they can prevent dementia.
A review of published research evaluated the evidence from clinical trials on behavior and lifestyle changes to prevent or delay Alzheimers or age-related cognitive decline. The review found encouraging but inconclusive evidence for three types of behavioral changes : physical activity, blood pressure control, and cognitive training. The findings mean that interventions in these areas are promising enough that researchers should keep studying them to learn more. Researchers continue to explore these and other interventions to determine whether and in what amounts or forms they might prevent dementia.
Watch a video below that highlights conclusions and recommendations from the research review.
Read Also: Neurotransmitter Involved In Alzheimer’s
Family History By The Numbers
Studies of family history say that if you have a close relative who has been diagnosed with Alzheimer’s diseasethe most common form of dementia in older adultsyour risk increases by about 30%. This is a relative risk increase, meaning a 30% hike in your existing risk.
If you are age 65, the risk of being diagnosed with Alzheimer’s is 2% per year, although this also means a 98% chance per year of not developing Alzheimer’s. In absolute numbers, a 2% annual risk means that two out of 100 65-year-olds will develop dementia every year.
Family history raises the 2% annual risk by about 30%, to 2.6% per year. That means going from 20 cases in a group of 1,000 to 26 in 1,000, or six additional cases in 1,000. “So the absolute increase is relatively small,” Dr. Marshall says.
Age raises the chance of Alzheimer’s more than family history. People in their 70s have a 5% chance of being diagnosedmore than twice that of people in their 60s. Family history raises this by 30%, from 5% to 6.5%. Again, the absolute change is relatively small.
Genetic Testing For Alzheimer’s Disease
A blood test can identify which APOE alleles a person has, but results cannot predict who will or will not develop Alzheimer’s disease. Currently, APOE testing is used primarily in research settings to identify study participants who may have an increased risk of developing Alzheimer’s. This knowledge helps scientists look for early brain changes in participants and compare the effectiveness of possible treatments for people with different APOE profiles.
Genetic testing is also used by physicians to help diagnose early-onset Alzheimers disease and to test people with a strong family history of Alzheimers or a related brain disease.
Genetic testing for APOE or other genetic variants cannot determine an individuals likelihood of developing Alzheimers diseasejust which risk factor genes a person has. It is unlikely that genetic testing will ever be able to predict the disease with 100 percent accuracy, researchers believe, because too many other factors may influence its development and progression.
Some people learn their APOE status through consumer genetic testing or think about getting this kind of test. They may wish to consult a doctor or genetic counselor to better understand this type of test and their test results. General information about genetic testing can be found at:
Don’t Miss: Colors For Alzheimer’s Awareness
The Research Is Mixed But Whats Clear Is That The Benefits Of Statins Typically Outweigh The Risks In People Who Need Them
Experts know that statins are good for your heart they can lower “bad” LDL cholesterol and reduce your chances of having a heart attack or stroke by 25% to 30%. But what effect do statins have on your brain?
In 2012, questions surfaced when the FDA issued a warning that statin users had reported short-term cognitive impairment when taking the drugs.
A study published June 29, 2021, by the Journal of the American College of Cardiology aimed to shed some additional light on this issue. Researchers looked at data on statin use among 18,446 people, ages 65 or older, who had taken part in a large randomized trial of aspirin. The researchers found that over a follow-up period of almost five years, people who took statins werent any more likely than non-users to have dementia. The same was true when it came to other changes in cognition, memory, language, executive function, or a measure called psychomotor speed, which measures how quickly someone can process information. They also found no differences between different types of statins.
However, while these findings were good news, they may not be the final word on this issue. Although this particular study found no link between statins and dementia, the research into statins and brain-related effects over all is best described as inconsistent, says Dr. JoAnn Manson, chief of the Division of Preventive Medicine at Harvard-affiliated Brigham and Womens Hospital.