Tag Archives: dementia

Can a Healthy Lifestyle Reduce Genetic Risk for Dementia?

February 8, 2020

A combination of genetic and lifestyle factors can play a role in determining an individual’s risk of Alzheimer’s disease and other types of dementia. Although most cases occur in older adults in whom multiple genes influence overall risk, high levels of LDL cholesterol, diabetes, atherosclerosis, and other health factors can further elevate risk. While some risk factors may be difficult to mitigate, others are easily modifiable – for example, weight and lipid management through a combination of lifestyle changes.

A growing body of evidence suggests that individuals who lead a healthy lifestyle – avoid smoking tobacco, engage in regular physical activity, and consume a health diet – have a lower risk of developing dementia. Previous research has investigated the impact of lifestyle factors on many other health conditions such as cardiovascular disease, however, the extent to which these variables can influence dementia risk is unknown. A new study published online in JAMA, uses data from a large population-based cohort to investigate whether adherence to a healthy lifestyle can offset existing genetic risk for dementia.

Association of Lifestyle Habits with Dementia Risk

Led by Ilianna Lourida, PhD from the University of Exeter Medical School, a team of researchers conducted a retrospective cohort study of nearly 200,000 European adults aged 60 and above to investigate whether a healthy lifestyle is associated with a reduced risk of dementia – regardless of genetic factors. At baseline, none of the participants had cognitive impairment or dementia. The main outcome was the incidence of all-cause dementia identified through hospital records.

Researchers calculated a polygenic risk score comprised of common genetic variants linked to Alzheimer’s disease and dementia risk, as well as a weighted healthy lifestyle score – which included smoking status, physical activity levels, dietary patterns, and alcohol consumption.

Healthy Lifestyle May Reduce Dementia Incidence

A total of 196,383 participants with a mean age of 64.1 were followed for a median of 8 years, during which there were 1,769 cases of incident all-cause dementia. Overall, over 68% of the cohort had followed a healthy lifestyle, 23.6% followed an intermediate lifestyle, and 8.2% followed an unfavorable lifestyle. Researchers found that 20% of individuals had high polygenic risk scores, 60% had intermediate-risk scores, and 20% had low-risk scores.

Of those with a high genetic risk, 1.23% developed dementia, compared with 0.63% of participants with low genetic risk. Meanwhile, participants with both a high genetic risk and unfavorable lifestyle developed dementia at a rate of 1.78% compared with 0.56% of participants with low genetic risk and a favorable lifestyle. Researchers found no significant interaction between genetic risk and lifestyle factors. Among individuals with high genetic risk, 1.13% of those leading a healthy lifestyle developed dementia, in comparison with the 1.78% with unfavorable lifestyle.

Risk Reduction

Dr. Lourida and her team found that an unfavorable lifestyle coupled with high genetic risk was significantly associated with a higher risk for developing dementia in older adults without pre-existing cognitive impairment. Meanwhile, a healthy lifestyle was associated with a lower dementia risk even among participants with a high genetic risk. While there was no significant interaction between genetic risk and a healthy lifestyle, a favorable lifestyle was associated with reduced dementia risk regardless of genetic factors.

Overall, the authors found an absolute risk reduction for dementia among the high genetic risk group of 0.65% associated with leading a favorable lifestyle.

The study’s authors acknowledged the trial’s limitations. Firstly, the lifestyle score used in calculations was not independently validated to indicate a high-risk lifestyle outside of trial conditions. Furthermore, there was a possibility of unmeasured confounding and reverse causation. In addition, lifestyle factors were self-reported and some cases of dementia might not have been recorded in medical records or death registers. Nonetheless, the study expands on current knowledge of neurodegenerative diseases and their connection to lifestyle choices.

“This risk reduction implies that, if lifestyle is causal, 1 case of dementia would be prevented for each 121 individuals per 10 years with high genetic risk who improved their lifestyle from unfavorable to favorable,” authors wrote. Aside from the many mental and physical health benefits associated with leading a health-conscious lifestyle, doing so may also contribute to lowering dementia risk by reducing oxidative damage, having anti-thrombotic and anti-inflammatory effects as well as increasing cerebral blood flow. Thus, it is important to encourage patients to follow a favorable lifestyle and support lifestyle interventions when necessary, especially in cases of high genetic risk.

Preventing Dementia in Patients with Mild Cognitive Impairment

July 10, 2019

According to data from the American Academy of Neurology (AAN), an estimated 6% of people worldwide suffer from mild cognitive impairment (MCI) in their 60s, and 37% are affected by age 85. Although patients with mild cognitive impairment have an increased risk of developing dementia, the condition does not always worsen and growing research aims to determine the underlying mechanisms linking the two. The progression from MCI, a slight but noticeable change in cognitive function, to dementia is not automatic; about 15% of MCI cases develop into dementia.

Continue reading →

How to Save Your Brain

June 23, 2017

A report published by the National Academies of Sciences, Engineering and Medicine (NASEM) cites promising evidence indicating that active cognitive training, blood pressure management, and physical activity may collectively help stave off age-related cognitive decline and dementia.

In 2015, the Alzheimer’s Association released similar findings that identified two critical activities that could minimize the risk of cognitive decline: increasing physical activity, and improving cardiovascular health. Dan G. Blazer, a member of the NASEM committee that conducted the study and the J.P. Gibbons Professor of Psychiatry Emeritus at Duke University Medical Center, states: “What is good for the heart is good for the brain. Therefore, exercise and controlling high blood pressure are good for the brain.” While controlling blood pressure is good preventive practice to combat heart disease, it may also reduce memory less and dementia—likely because high blood pressure damages delicate blood vessels in the brain.

In terms of diet, a study released by Temple University found that extra-virgin olive helped fend off Alzheimer’s in mice. The mice fed a diet rich in extra-virgin olive oil showed better learning and memory skills than those who did not receive the diet. While the evidence surrounding diet is not as conclusive and plentiful as the research regarding exercise, the panel singled out diets that emphasized whole grains, fruits and vegetables, low-fat dairy, and lower levels of salts.

Cognitive training has been receiving more attention recently, referring to tools and tactics engineered to improve reasoning, problem-solving, memory retention, and processing speed. In a randomized control trial reviewed by the committee titled “Advanced Cognitive Training for Independent and Vital Elderly,” participants who received cognitive training in processing speed and reasoning deduction demonstrated less decline than those who did not, over a time span of ten years.

More than 5 million Americans have been diagnosed with Alzheimer’s, the most common form of dementia, and the number is only expected to increase as the population ages. Statistics show that by 2050, numbers could reach up to 16 million. There is no cure, and few effective treatments. Yet the evidence suggests that these lifestyle changes may actively reduce risk, or at least delay the onset of dementia. Dr. Richard Hodes, director of the National Institute on Aging, advised people to “Try and avoid the tendency to sit down, watch television for endless hours at night. Get out there, do something.”