Genes, Lifestyle and the Risk of Alzheimer's Disease

Senior man

Alzheimer's disease is a huge public health issue and touches so many families. With no effective drugs to treat the disease as of yet, the emphasis is still on prevention. We're advised to make lifestyle choices to keep our brains healthier and lower our personal risk of dementia. These are risk factors we can control.

But then, there are the risk factors over which we have no control. Age is a top factor, and genes also figure in. Everyone knows their age, and today, more and more people are learning their genetic risk.

The most common genetic risk factor is a variety of a certain gene, commonly called the APOE4. If one of your parents has this gene (and about one-fourth of the world's population does), your risk of Alzheimer's is tripled. A person who inherits the gene from both parents is eight to 12 times more likely to develop the disease.

When a person learns that they have the APOE4 gene, it's understandable that they would be concerned, especially if a parent or other close relative has developed Alzheimer's. However, it's important to know that having the APOE4 gene doesn't make it inevitable that a person will develop Alzheimer's.

We know a lot more about Alzheimer's than we used to! Until fairly recently, the disease could only be definitively diagnosed after a person passed away, when an autopsy of the brain revealed the typical amyloid plaques and neurofibrillary tangles that cause the death of and loss of connection between neurons (nerve cells). Brain autopsies weren't routinely performed, so it wasn't until recently that scientists realized that plaques and tangles don't necessarily lead to outward signs of the disease.

In one recent study, Northwestern University researchers examined the donated brains of people who lived to be 90 or older. They found that several of the brains had "widespread and dense Alzheimer's plaques and tangles ... considered full-blown Alzheimer's pathology," even though they belonged to people who had excellent memory and thinking right up until their deaths. Said neurologist Changiz Geula, "This is amazing. We never expected it. It tells us there are some factors that protected their brains."

What were those factors? Research suggests genetic advantages, but also some things that we can control. Ongoing research on thousands of elders is pinpointing brain-healthy lifestyle choices that could reduce both the brain changes and the symptoms of Alzheimer's.

But what about people with the APOE4 gene? Can their risk be lowered, too?

In January 2018, a study published in JAMA Neurology confirmed that it can. Researchers from the University of Finland studied the ongoing cognitive health of a group of seniors. Half the group were enrolled in a program of healthy lifestyle training — and at the end of the study, this group performed significantly better on memory tests, whether they had the APOE4 gene or not!

"Many people worry that genetic risk factors for dementia may thwart potential benefits from healthy lifestyle changes. We were very happy to see that this was not the case in our intervention," noted study author Alina Solomon. "The findings show that enhanced lifestyle counseling prevented cognitive decline despite the presence of the risk gene. Analyses carried out within the groups also indicate that the intervention results might even be better in carriers of the APOE4 gene."

Which lifestyle choices make a difference? The researchers focused on four in particular:

1. Exercise. Physical activity can delay development of the disease. A recent study from the University of Maryland even showed that "exercise training may stimulate brain plasticity and restore communication between brain regions that may have been lost through Alzheimer's disease." And couch potatoes who don't have the APOE4 gene, take note! A recent study from McMaster University in Canada found that "sedentary older adults with no genetic risk factors for dementia may be just as likely to develop the disease as those who are genetically predisposed." In other words, don't be complacent if you have "good genes." Said study author Prof. Jennifer Heisz, “The important message here is that being inactive may completely negate the protective effects of a healthy set of genes.” Ask your doctor to recommend an exercise program, and add extra physical activity to your life whenever you can.

2. Diet. The foods we eat can protect our brains, or raise our risk of health conditions that damage the brain, such as hypertension, heart disease, diabetes and obesity. A number of diets have proven beneficial for the brain, including the Mediterranean diet, the MIND diet, the DASH diet and other eating plans that are rich in vegetables, fruits, berries, whole grains, nuts, fish, poultry, olive oil and other healthy fats — and which include very little red meat, unhealthy fats, refined sugars and carbohydrates, and other processed foods. At the 2017 Alzheimer's Association International Conference, multiple experts agreed that older adults who consistently followed this type of diet lowered their risk of cognitive impairment by up to 35 percent! Talk to your doctor or a dietitian about the diet that's right for you.

3. Mental stimulation. There's been a lot of talk about "brain training." Can we exercise our brains like we do our muscles? We do know that using our brains builds "cognitive reserve" — as the Alzheimer's Association explains it, "increasing the connections between neurons, enabling the brain to use alternate routes of neuron-to-neuron communication to complete cognitive tasks when the usual routes have neuronal gaps because of Alzheimer's." This means our brains might be looking for a bit of information, run into a roadblock, and be able to take another path. People with more years of formal education have a lower risk of dementia — but it's never too late, say experts. Take a class, learn a language, join a music club, do puzzles, travel — above all, always be learning something new.

4. Social interaction. Spending time with others provides high-level brain stimulation. Many areas of our brains come into play when we're talking to others, sharing information or cooperating on a task. Loneliness is very stressful for our highly social species. As we saw in the March 2018 issue of the Caring Right at Home online newsletter ("Helping Senior Loved Ones Expand Their Social Horizons"), maintaining strong social networks has been linked to slower cognitive decline. Make an extra effort to nurture longtime relationships, while continuing to develop new ones. (By the way, April is National Volunteer Month, a great time to remind seniors that there's a volunteer opportunity for almost everyone! Seniors are the age group most likely to volunteer — why not join the ranks?)

Other factors figure in. Managing our health conditions, protecting against head injuries, avoiding smoking and overuse of alcohol, and maintaining a healthy weight are part of the equation. And whether or not a person has an elevated genetic risk, learning about services and care options for people with memory loss can actually lower our anxiety about the future and whatever it brings us.

Right at Home, Inc. is a national organization dedicated to improving the quality of life for those we serve. We fulfill that mission through a dedicated network of locally owned providers of in home care services.