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Is Dementia Genetic Or Environmental

But How Can You Measure Lifestyle And Genetic Risk

World Alzheimer’s Day: Genetic, lifestyle and environmental factors affect brain FRANCE 24

The investigators hand-picked a list of common lifestyle factors, including smoking, alcohol consumption, physical activity, and diet, and created a score. A low score denoted a bad lifestyle. A high score denoted a good lifestyle.

However, taking this approach to measure lifestyle risk has several pitfalls:

  • First, a vast number of factors comprise lifestyle and environment beyond smoking and physical activity. So any list may be arbitrary. In fact, our research team has argued that choosing a candidate list doesnt capture our complex lifestyles and may lead to false findings. For example, what exactly constitutes a healthy diet?
  • Second, using a score makes the individual roles of the factors unclear.
  • Third, if connections between factors influence both the score and dementia, then the score might be a weak proxy for other variables that werent considered. In other words, if weight is associated with diet and dementia, then it is hard to untangle the association of diet.

To create the genetic risk score, the investigators used all genetic variants previously identified by a genome-wide association study of Alzheimers disease. These gene variants are strongly associated with patients who have Alzheimers compared with healthy controls). Using this information, the researchers constructed a polygenic risk score.

Exercising Your Physical Body

There are certainly many reasons to be physically active, like reducing your odds of heart disease, stroke and diabetes. Lowering your blood pressure, losing weight, and avoiding or helping to recover from depression are other benefits. But did you know that exercise is also great for your brain and memory? Physical exercise improves the functioning of neurotransmitters, the chemical messengers in the brain responsible for communication across brain cells for such things as controlling memory and other cognitive functions, regulating mood, influencing appetite, and enhancing sleep quality.

Discuss with your healthcare provider the best way to begin an exercise program, or to safely increase it once youve already started. Then move ahead with confidence that you are helping to keep your heart healthy and your brain operating at top capacity by doing so.

Lifestyle And Genetics Both Play A Small Role In Dementia

The lifestyle score was associated with dementia risk. Second, the genetic score was also associated with dementia. In other words, individuals with worse scores were at higher risk for dementia. The researchers further found that genetic risk and lifestyle appeared to act independently of each other. For example, individuals with both an unhealthy lifestyle and a high genetic risk score had almost two and a half times more risk than individuals with a low genetic score and healthy lifestyle.

However, this research was not designed to prove whether lifestyle and environment or genes cause dementia. A lot more could explain the differences between people who develop dementia. If populations at high genetic risk changed their lifestyle, and if the lifestyle was known to be the cause of AD , one out of 121 dementia cases would be prevented in 10 years. This is significant, but what number of lifestyle modifications would it take for the prevention of AD in 10, 50, or even 120 people? Do genetics even matter?

Second, the genes and lifestyle did not appear to work together or they werent synergistic in dementia risk. Specifically, this means that individuals with both bad genetic and lifestyle scores were not at risk for developing dementia any more than the sum of the parts or the individual scores alone.

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Genetic And Environmental Risk In Dementia

Although a small proportion of cases of dementia are caused directly by gene mutations, the majority of cases are sporadic with no known cause. However, there are a number of factors that can increase our risk of developing dementia, including both environmental and genetic factors. Although we have no control over some risk factors, such as ageing and our genetics, many lifestyle risk factors are modifiable. Understanding dementia risk factors, both environmental and genetic may result in opportunity to implement interventions to reduce the risk of dementia lower the burden of dementia as our population ages.

Genetic And Lifestyle Risk Factors

Lifestyle changes to stave off Alzheimer

The short answer is that the risk of developing dementia is related to a combination of genetics and lifestyle, with age being the biggest risk factor.

In most cases, genetic risk factors come from small influences of many genes, rather than one mutation being responsible for the entire genetic effect. Therefore, it is unlikely that a child will inherit every dementia-related mutation that a parent has.

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Coaction Of Genes And Environments

As described above, the evident increases in unique environmental variance with age across cognitive domains may signal possible gene-environment interplay, particularly gene-environment interactions . We conducted the first longitudinal study demonstrating GxE interaction processes for memory-laden tasks using within-pair monozygotic twin methods , based in part on the work of R.A. Fisher nearly 100 years ago . The benefit of identical MZ twins is that pair differences are a function of each twins unique experiences. To the extent that particular genes coupled with different environmental exposures may influence the magnitude of pair differences, GxE may be present.

Figure 3. Semantic memory change among identical twin pair members : Trajectories in randomly selected pairs Pair differences in quadratic rate by APOE 4 and Association of pair differences in quadratic rate with differences in depressive symptoms by APOE 4.

Note: Panels B and C adapted from . Pair differences normalized .

Silent Risk For Dementia

PM2.5, also known as soot, consists of microscopic particles of chemicals, car exhaust, smoke, dust and other pollutants suspended in the air. An estimated one in six Americans lives in counties with unhealthy levels of particle pollution.

We have been investigating whether PM2.5 may accelerate the brains aging processes at the preclinical stage the silent phase of the disease before any symptoms of Alzheimers disease and related dementias appear.

In the first U.S.-based nationwide study to link PM2.5 exposure and cognitive impairment, published in 2017, we found older women were almost twice as likely to develop clinically significant cognitive impairment if they had lived in places with outdoor PM2.5 levels exceeding the U.S. Environmental Protection Agencys standard than if they hadnt. Because we worked with the Womens Health Initiative Memory Study, which followed the participants closely, we were able to account for other dementia risk factors, such as smoking, lack of exercise and hormone therapy.

In a new study, we wanted to see how the brains of older people were changing if they had experienced different levels of PM2.5 in the years before Alzheimers symptoms began.

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Nature Vs Nurture And Alzheimers Disease

There has long been a debate as to whether most of the factors that make us who we are come from genetic or environmental influencesthe so-called nature vs. nurture debate. Scientists seem to agree that both genetic influences AND environmental influences are often BOTH at play. While there are a number of diseases that cause dementia, Alzheimers disease is by far the most common. Genes definitely play a role in AD risk however, a recent report on the genetics of AD estimated that genetics currently explain only about one third of the cases of AD . This is very good news indeed, and suggests that a large part of our risk for eventually developing AD comes from environmental influences. There is a growing body of evidence that through healthy lifestyle choices, we can indeed have some impact on our brains health.

Reducing Your Risk Of Developing Dementia

Genetics & Dementia

As mentioned earlier, genes increase the risk of dementia but do not cause it in most cases. There are multiple risk factors associated with dementia, including cardiovascular diseases, diabetes, and smoking, that can be managed to help in preventing dementia. Maintaining a healthy lifestyle with physical exercise, a balanced Mediterranean diet, low levels of alcohol intake and abstinence from smoking can help in reducing the risk of dementia.

Individuals with substance use disorders are often at an increased risk of developing dementia. In addition, family members of an individual with dementia may turn to substances to deal with the stress of caring for their loved one. If you or a loved one suffers from a substance use disorder, The Recovery Village can help. Contact us today to learn about specialized treatment programs that can work well for your situation.

Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

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Exposome Originally Used To Understand Cancer Risk

The exposome concept was first proposed by cancer epidemiologist Christopher Paul Wild in 2005 to draw attention to the need for more data on lifetime exposure to environmental carcinogens. The exposome is now a mainstream model, eclipsing previous characterizations of environmental factors as affecting risk one by one.

Epidemiologists have been using the exposome to have a broader outlook on whatever theyre studying, whether its lead toxicity or head trauma, Finch said. Its our point that a number of things need to be considered for interaction and many effects are additive.

Some of the environmental interactions researchers want to build into the larger Alzheimers Disease Exposome.

The authors say the exposome concept extends and leverages the National Institute on Aging/Alzheimers Association Research Framework a consortium that follows clinical cohorts by brain imaging for biomarkers to assess neurodegeneration to include gene-environment interactions across individual age and duration of exposure.

List Of Dementia Environmental Risk Factors Drawn Up

A shortlist of environmental factors that may contribute to the risk of developing dementia has been drawn up by experts.

The list includes exposure to air pollution and a lack of vitamin D, although researchers warned that there are not yet any solid conclusions.

It has been put together by Edinburgh University’s Alzheimer Scotland Dementia Research Centre.

The centre believes future research should focus on the shortlist.

Dementia is known to be associated with lifestyle factors such as high blood pressure in mid-life, smoking, diabetes, obesity, depression and low educational attainment, as well as genetic factors.

But the Edinburgh researchers said a third of dementia risk was unexplained, and they want to determine whether other issues are at play, including the environment.

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What Is Dementia And What Makes It So Complex

Dementia describes groups of specific diseases characterized by symptoms such as memory loss. The most common type of dementia is Alzheimers disease . People with AD have plaques in their brains made of up of tangled proteins, and many researchers have hypothesized that these plaques are the cause of the disease.

Another common type of dementia is vascular dementia. This is thought to be induced by damaged blood vessels in the brain, such as from a stroke.

Experts believe both genetic factors and modifiable lifestyle factors all play a role in the development of dementia, perhaps in concert.

Handling Stress In Positive Ways

Dementia  Different Type Of Prevention Strategies

Life is filled with challenges that include simple every day sources of stress to more long-lasting major trials that can impact health. Studies have shown that stress from long-term types of adversity, that are not well managed, have the effect of killing brain cells in the area of the brain called the hippocampus, which is responsible for learning and memory, putting the person at higher risk of later developing Alzheimers disease and other dementias .

Learning ways to cope with stress in your life can minimize its effect on brain health. Self-help books, stress management workshops/classes and even counseling therapy can all help you develop new and more positive ways to look at and manage the sources of stress in your life and how you react to the trials you experience. Having a more problem-focused approach to stress coping, where you address or fix those things you can control, is also good for brain health. Such approaches reduce depression risk, a condition linked to AD risk . If you tend to react to stress in less productive ways , it may be one the best things you can do for yourself to seek out some help to better manage your stress.

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Genetic Testing For Hereditary Dementia

If you have or had a parent with Alzheimers disease, its usually not recommended that you get genetic testing.

Testing positive for the gene may not change your medical treatment. It also does not mean you will get Alzheimers. But it could create anxiety and stress and affect your quality of life.

So while genes may increase your risk, there are ways to decrease it, too. The best course of action to reduce your risk factors for cardiovascular disease, including high blood pressure, high cholesterol, and diabetes.

The Alzheimers Associations guidelines include eating a healthy diet, maintaining a healthy weight, and exercising regularly. Its also important to maintain social connections and keep your brain active by learning a new skill, finding a hobby, or taking a class.

What Factors Might Affect Dementia Risk

Genes which are not considered modifiable and lifestyle factors like physical activity and diet which are considered modifiable play potential roles in different forms of dementia.

A recent study in JAMA attempts to estimate how much genetic and lifestyle factors influence risk for dementia by querying individuals who pledged to be part of a UK-based biobank. Biobanks link large collections of biological information, such as genetics, with health and disease status gleaned from medical records. Using data in large biobanks, scientists can look at how the environment which includes lifestyle choices and genetics work together to increase risk for disease.

In the JAMA study, researchers tapped hospital records and death registries to collect diagnoses in 200,000 white British individuals age 60 or older.

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Epigenetics And The Risk Of Dementia

Studies conducted on post-mortem brain tissues are showing the potential association between Alzheimers and epigenetic alteration of gene function. Since the investigation is on people who have succumbed to the brain disease, it is hard for researchers to understand the exact role of epigenetics in developing the neurodegenerative brain disorder.

For instance, experts are not sure if the epigenetics alteration plays a causal role or occurs due to the brain disorder. Some researchers also speculate if the epigenetic changes are just a consequence of aging.

In this study that was conducted by two teams, researchers screened DNA from brain tissues of Alzheimers patients. They searched for chemical changes that cause the genes to switch off through methylation.

Such epigenetic alterations do not change the DNA sequence that a person has inherited. Instead, they change the pattern in which genes are expressed, which influences the development of the mental disorder.

The study also found that the greatest methylation differences were in tissues in the entorhinal cortex, the part of the brain that suffers significant damage due to Alzheimers. The research witnessed that a gene known as ASK1 correlated with Alzheimers.

This gene is responsible for the secretion of ankyrin 1, which is present in the outer membrane of cells and is crucial for maintaining cell structure.

Your Risk Of Dementia: Do Lifestyle And Genetics Matter

An environmental factor: TBI and dementia research

Globally, Alzheimers disease and other forms of dementia are a major burden on individuals and communities. To make matters worse, there are few treatments to combat these complex illnesses. Even the causes of dementia are widely debated. Sadly, clinical trials for drugs to stop or even slow its progress have come up short. Taking a different tack, some experts hope to intervene before people are diagnosed with dementia by encouraging lifestyle changes.

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What Kind Of Dementia Is Hereditary

Dr. Rx

Just because your family member had dementia does not mean you will also get it. Although you are at higher risk, there are also a number of things you can do to lower your risk. Dont smoke, get regular exercise, eat healthfully, manage health issues , maintain regular social connection, and do activities that challenge your brain . Dr. Wegner

Researchers have identified several genes that increase the riskof Alzheimers, such as the APOE-e4 gene. An estimated 40% to 65% of those diagnosed with Alzheimers have this gene.

Vascular dementia is less likely to be influenced by genes. It is more likely linked to risk factors for heart disease like high blood pressure, being overweight, having a sedentary lifestyle, or diabetes.

About one in three of frontotemporal disorders may be hereditary.

New Frontiers For Ad Prevention And Treatment

New horizons for prevention and treatment might include how risk might be different for individuals of varied genetic ancestries and ethnicities both here in the US and abroad. The risk may also be different between males and females. Finally, biobanks can only describe association, not causation, between changes in lifestyle and dementia risk. To determine causation, randomized trials are required, and a new US-based randomized clinical trial called POINTER is now underway.

Trying to live a healthy lifestyle, despite its elusive definition, seems to be an obvious way to prevent dementia. What remains to be seen is how studies using biobanks can be informative about the millions of people who already may be suffering from the disease.

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