Alzheimer’s Risk: Do You Want to Know?

By Matt McMillen , Reviewed by Arefa Cassoobhoy, MD, MPH 

If a test could tell whether you’ll get Alzheimer's disease someday, would you want to know? And if so, what would you do with that knowledge?

These questions are becoming more and more important as researchers close in on tools to predict your risk of Alzheimer’s disease decades before symptoms start to appear.

“Primary care physicians, in the disease’s early stages, [eventually] could be able to say, ‘It looks like there’s a problem here’ through a blood test, a saliva test, or by looking at the retina,” says Dean Hartley, PhD, director of science initiatives for the Alzheimer’s Association. “But there’s no medical test now. It’s all in the research stage.”

For now, only genetic tests are available to the general public. They can spot genes linked to a higher risk of Alzheimer’s, such as the ApoE4 gene. But genetic tests aren't conclusive. Not everyone whose test result says they have ApoE4 will get Alzheimer's, and many people who don’t have that gene will get the disease.

And if you have the gene, there isn’t much you can do yet, aside from making lifestyle changes that may be preventive. “You can get the ApoE4 test at your doctor’s office, but I and many of my colleagues rarely offer it, because we don’t have any treatments to offer if we determine that patients are at higher risk,” says Alzheimer’s researcher Liana Apostolova, MD, a professor at the Indiana University School of Medicine.

Also, knowing your risk could come with a price. Seven years ago, Jamie Tyrone learned unexpectedly that she had two copies of the ApoE4 gene.

“I went into a deep, dark hole,” says Tyrone, 55, a former nurse who lives in San Diego. “This information was very anxiety-provoking, to the point that I was diagnosed withPTSD [post-traumatic stress disorder]. Knowing has done me harm.”

Tyrone says Alzheimer’s was not on her radar when she was tested for a variety of genetic disorders as part of a research study. Being unprepared for the news, she says, made her anxiety worse.

Eventually she learned to cope. She started to take better care of herself, exercising and improving her diet, meditating and doing brain-twisting puzzles purported to strengthen memory and focus. And she became involved with research into the disease. She founded B.A.B.E.S., Beating Alzheimer’s By Embracing Science, a non-profit that supports research into the disease and encourages people to get involved.

Tyrone wants others to learn from her experience.

“I’m choosing to heal by talking about it,” she says. “I don’t want people to go through what I went through.”

New Ways to Detect Alzheimer’s Disease

The biggest advance toward the early prediction of Alzheimer's, Hartley says, is using PET scans to show the buildup of beta amyloid plaques in the brain. The plaques are a risk factor for the disease, and in the past they could be seen only during an autopsy.

“This is an opportunity to see into the live brain,” Hartley says.

The FDA has approved PET amyloid imaging for use in some clinical trials and to help diagnose dementia patients, but not to predict the development of the disease -- at least not yet.

“PET imaging with amyloid will be the first way of approaching prediction,” Apostolova says. MRI will also be useful, she says, as will PET imaging for tau proteins, another sign of disease.

But, she continues, amyloid PET scans are expensive, not readily available, and they expose patients to radiation.

“What if there’s another way to get at the answer of who’s at risk?” she asks.

Research Apostolova led while at UCLA resulted in a simple blood test that picks up biomarkers -- or proteins in the blood -- linked to Alzheimer’s. Along with other tests, it one day may help predict the disease. She published her early findings in January in the journal Neurology.

Researchers are studying several other new tests:

• A saliva test that identifies biomarkers linked to Alzheimer’s disease.
• A combination of cognitive tests, MRI scans, and analysis of proteins found in cerebrospinal fluid -- fluid in the brain and spinal cord that can predict mild cognitive impairment, or thinking problems, 5 years before symptoms become apparent.
• Measurements of the protein neurogranin, a potential Alzheimer’s biomarker found in fluid in the brain and spinal cord.
• Tests that uncover the deterioration of your sense of smell may indicate Alzheimer’s.
• Eye exams that can measure beta amyloid buildup.

All of these tests remain experimental, and their effectiveness remains to be seen.

“Saliva tests, blood tests, and things like that are not ready for prime time,” Hartley says.

Knowing Your Risk

If you do learn your risk of Alzheimer’s -- through a genetic test or, eventually, through one of these still-experimental tests -- what can you do with that knowledge? And how would it affect you? After all, with no viable treatments available to slow, stop, or prevent the disease -- only drugs that may improve symptoms in some people for a short time -- there’s little doctors can offer you.

“Some people would want to know so they can plan things out, such as long-term care insurance and end-of-life decisions, while others would not want to know,” says David Salmon, PhD, of the Shiley-Marcos Alzheimer’s Disease Research Center at the University of California, San Diego. “It’s a personal decision. It’s hard to say what the best advice would be.”

Salmon’s research suggests that knowing you’re at risk can have bad consequences. You're more likely to rate your memory worse and do worse on a memory test than someone with the same risk who is unaware.

“We don’t think it’s depression, but we didn’t measure anxiety and stress, so we don’t know if the disclosure increased anxiety and that it’s the anxiety that causes you to have memory problems,” Salmon says.

But other research suggests that knowing your genetic risk does not up your chances of depression, anxiety, or distress. Jason Karlawish, MD, an Alzheimer’s expert and medical ethicist at the University of Pennsylvania, has studied middle-age adults with a family history of Alzheimer’s.

If people get their mood and well-being assessed before they get tested, "they have minimal problems with mood and well-being after learning the results,” Karlawish says. “We don’t have data from persons who are older and plausibly closer in age of onset to AD.”

Karlawish is involved in a study of an experimental Alzheimer’s drug known as solanezumab. The drug, made by Eli Lilly, targets amyloid plaques and may delay the onset of cognitive decline. It is now being tested on people who don’t have Alzheimer’s symptoms but whose PET scans have shown the presence of such plaques, a potential early warning sign of the disease.

It’s among several meds that may prevent or slow Alzheimer’s from getting worse that are being studied in people long before they show symptoms.

Karlawish’s previous research suggests that that knowledge may motivate people to change their lifestyles. That’s what Tyrone eventually began to do. She has improved her diet and her exercise habits, she’s at work on a book about her experiences, and she’s become involved in Alzheimer’s research, such as studies into new medication. That’s something she highly recommends -- as does Karlawish -- for people who know they’re at risk.

“Yes, it’s partially selfish, because you’re getting something as well as giving something,” she says. “You’re at the forefront of cutting-edge research.”

But if you don’t yet know? “I would ask them, why do you really want to know this information? And can you make changes without knowing that information?” Tyrone asks. “It may be anxiety provoking. Is it really healthy to know this information or is not healthy? What are you going to do with it?”

We CAN Handle the Truth: The Facts on Alzheimer’s

Journalist and Alzheimer’s disease advocate Maria Shriver shares her takeaways from the WebMD and Shriver Report Snapshot: Insight into Alzheimer’s Attitudes and Behaviors.

By Maria Shriver
Special to WebMD Health News

“Denial is the worst form of the truth.”

During the time it takes for you to read this piece, try to put your denial impulse aside and take a hard look at the truth about Alzheimer’s. Because the fear that causes you to deny things – like our risk of getting this mind-blowing disease – can actually be the motivator you need to stop ignoring the facts and join me in doing something about it.

So here’s the truth: Our brand new WebMD and Shriver Report Snapshot: Insight into Alzheimer’s Attitudes and Behaviors, reveals that almost all of us (96%) have heard of Alzheimer’s disease … so we can no longer deny that it exists. Nearly 4 in 5 of us know, or have known, someone that has been diagnosed with it, which tells us that the vast majority of us not only know about it, they actually have experience with someone who has had or is living with Alzheimer’s.

But even with all of that first-hand experience, we aren’t doing much about it. Although 67% of people say they would actually like to know their risk for getting Alzheimer’s disease, when offered a list of ways to do that, more than 1 in 4 say they wouldn’t do any of them. Although two-thirds acknowledge that an Alzheimer’s diagnosis would cause their family great financial harm, nearly half say they have never considered the financial implications if they, or someone in their family, were to get the disease.

We know the risks and the reality, but we are in denial and unprepared as a nation to deal with it.

Why are Americans choosing to turn off and tune out when the risk-filled, pocket-emptying truth is right in front of us? Because denial is a protective mechanism. It keeps you safe until you are ready to handle the truth.

I have been fighting on the frontlines of Alzheimer’s since my own father was diagnosed with the disease in 2003. I get denial. Like millions of others I first denied what was happening to him. Then, I got scared. But after that, I got busy. Fighting this disease gave me the drive to push through my fear and land in a place of hope.

What am I hopeful about? I am hopeful about the exciting research that is happening in labs across the globe. Some of the world’s best and brightest are looking for a cure every day, some even say they’re getting closer – as the new cover of Time magazine implies.

But until a “miracle” drug is found, let’s not deny that someone in this country gets Alzheimer’s every 67 seconds. Let’s not refuse to act because there is no cure. There is no cure for cancer and still there are millions of people fighting it every single day. We need to fight the fear our denial is protecting us from and find the hope. Hope will allow us to accept the truth – that as many as 16 million people could have this disease by 2050 – and act on it.

I am hopeful that people now understand the connection between cardiovascular health and brain health. I am hopeful about the cutting-edge research that is showing a relationship between the foods we eat and their impact on our brain. I am hopeful that people are getting the message that our brains and our bodies are connected and what is good for our bodies is also good for our brains.

I am hopeful about companies like WebMD, Equinox, Vimmia and so many more, that are joining us in this fight. The truth is that getting educated, getting empowered and getting engaged is the way to stop the fear and find the hope.

I am hopeful that children of Boomers who might suspect that their parents are struggling with memory will get them to a doctor earlier because they are now more aware of what Alzheimer’s is and isn’t. If you’re wondering what the early signs are, just this week, theAlzheimer’s Association listed them for you. The fact is, every day 10,000 Baby Boomers turn 65. The time you waste denying that someone you love might have Alzheimer’s is time wasted getting them into a clinical trial or getting a new drug that could slow its progression. When I speak to anyone connected to this disease, one of the biggest regrets they have is the time they spent in denial. There’s so much shame around Alzheimer’s but the truth is you can sit down and have a conversation with your spouse, your parents, your loved ones about what they would want to do if Alzheimer’s showed up at your door today. Those who plan do better.

I am excited about talking to Lauren and Seth Rogen for my Architects of Change Live series– a series that profiles individuals from all walks of life who challenge what is. Seth and Lauren have done just that. They created Hilarity for Charity, they are shining a light on caregivers, raising money and asking young people on college campuses to get involved and think about prevention so they can help their parents and grandparents.

My Grandma Bev Died February 24, 2012 after a 10 year
battle with Alzheimer's. When she was diagnosed, she
never told a soul....

And I’m hopeful that women – the economic engine of this country – will join me in this fight because the vast majority of people diagnosed with Alzheimer’s are women. In fact, as The Shriver Report first reported, a woman in her early 60s is twice as likely to develop Alzheimer’s as she is breast cancer over the remainder of her life. Which is why I am excited about the mobilization of women through The Women’s Alzheimer’s Challenge – we’re raising money to fund research on women’s brains to get the answer. And we won’t stop until we do.

In fact, I am excited about ALL of the people who are engaged in this fight – spouses, children, political leaders. I am thrilled that the federal government just increased the amount of money devoted exclusively to Alzheimer’s research. It’s still not enough.

In an election cycle where it seems like we have nothing in common, one thing we all DO have in common is that we all have brains. And I haven’t met a person who isn’t terrified of losing theirs. So let’s brainstorm.

They say the truth can set you free. The truth about what Alzheimer’s is and isn’t and what we can and cannot do can set us free as a nation. I have faith in our country, and I know we can handle the truth and be brave enough to use our fear to propel us into action.

The best way to break through denial is to challenge it. We have the facts, we have the figures. And we have the fight. Let’s go and face it together.

Are Women the Key to Unlocking Alzheimer’s?

By Brenda Goodman, MA, Reviewed by Michael W. Smith, MD

 Alzheimer's disease hit the Schafferman siblings hard. Audrey was the first. She was diagnosed at age 65, about 3 years before her younger brother Gene. Audrey died in 2007. Gene would follow 5 years later.

Gene’s daughter, Donna Shore, recalls that the disease looked a lot different in her father than it did in her aunt.

“It seemed like Aunt Audrey went a lot faster than my father did,” says Shore, 58, of Littlestown, PA. She took care of Gene. He was so spry and vibrant that he was able to continue his favorite hobby -- dancing -- until just a year before his death. The nursing home staff called him “Gene, Gene, the Dancing Machine.”

Shore is especially grateful that her dad never forgot who she was, calling her by her nickname, Sparky, right up until his death.

Audrey’s loss, by contrast, seemed crueler. The unfailingly kind and loving mother and grandmother became paranoid. She accused her daughters of stealing her glasses and her social security checks -- when she could remember who her children were.

“I would have to go to the bathroom and cry, because I wasn’t used to my mother talking to me that way,” says Robin Broyles, 62, of Baltimore, MD.

When Audrey began sneaking out of the house and started confusing a closet for the bathroom, the family made the wrenching decision to put her in a nursing home. She died 18 months later.

Though the experience of the disease is highly individual, researchers think what happened in the Schafferman family may be part of a larger pattern, one that puts women in the epicenter of the Alzheimer's epidemic.

Studies show that by age 65, women have about twice the risk of getting the condition. About 1 in 6 women will get Alzheimer's after age 65, compared to about 1 in 11 men. About two-thirds of people in the U.S. with the disease are women.

Not only are women more likely to get Alzheimer's than men, but recent studies suggest the disease does its work more swiftly in women, causing them to decline faster -- and farther -- than men do, at least in the beginning.

 Alzheimer's disease hit the Schafferman siblings hard. Audrey was the first. She was diagnosed at age 65, about 3 years before her younger brother Gene. Audrey died in 2007. Gene would follow 5 years later.

Gene’s daughter, Donna Shore, recalls that the disease looked a lot different in her father than it did in her aunt.

“It seemed like Aunt Audrey went a lot faster than my father did,” says Shore, 58, of Littlestown, PA. She took care of Gene. He was so spry and vibrant that he was able to continue his favorite hobby -- dancing -- until just a year before his death. The nursing home staff called him “Gene, Gene, the Dancing Machine.”

Shore is especially grateful that her dad never forgot who she was, calling her by her nickname, Sparky, right up until his death.

Audrey’s loss, by contrast, seemed crueler. The unfailingly kind and loving mother and grandmother became paranoid. She accused her daughters of stealing her glasses and her social security checks -- when she could remember who her children were.

“I would have to go to the bathroom and cry, because I wasn’t used to my mother talking to me that way,” says Robin Broyles, 62, of Baltimore, MD.

When Audrey began sneaking out of the house and started confusing a closet for the bathroom, the family made the wrenching decision to put her in a nursing home. She died 18 months later.

Though the experience of the disease is highly individual, researchers think what happened in the Schafferman family may be part of a larger pattern, one that puts women in the epicenter of the Alzheimer's epidemic.

Studies show that by age 65, women have about twice the risk of getting the condition. About 1 in 6 women will get Alzheimer's after age 65, compared to about 1 in 11 men. About two-thirds of people in the U.S. with the disease are women.

Not only are women more likely to get Alzheimer's than men, but recent studies suggest the disease does its work more swiftly in women, causing them to decline faster -- and farther -- than men do, at least in the beginning.

Roberta Diaz Brinton, PhD, is a neuroscientist at the University of Southern California and a leading voice for studying the disease in women. She finds it puzzling that most Alzheimer’s research has been gender-blind, when women are in the majority of people with the disease.

“With AIDS, the AIDS research community did not look across the entire spectrum of everyone who was having sexual intercourse,” Brinton says. Instead, researchers focused on gay men having unprotected sex. “Focus on the people who have the biology,” she says.

New Clues in Women

One of the biggest risk factors for Alzheimer's disease -- in men or women -- is a gene that carries instructions for a protein called apolipoprotein E, which ferries cholesterol and beta-amyloid in and out of cells. Beta-amyloid are sticky fragments of proteins that build up in the brains of people who have Alzheimer’s disease.

Inheriting just one copy of the APOE4 gene results in a two to four times greater risk of Alzheimer’s disease. Inheriting two copies raises the risk nearly 15 times.

That higher risk doesn’t appear to be shared equally by men and women. A 2014 study of more than 8,000 people found that APOE4 had a stronger effect in women. For healthy men, having one copy of the gene only slightly increased the risk of memory problems compared to other men. For women, a single copy nearly doubled their risk of the brain changes and eventual Alzheimer’s compared to other women.

Other studies have questioned whether lifestyle factors and experiences particular to women may be playing a role. Women are more likely than men to get depression, which increases the risk for Alzheimer’s disease.

Education, it turns out, has a powerful connection with brain health. The more education a person has, the lower their risk for getting Alzheimer’s, leading researchers to wonder whether knowledge and learning may build the brain up, almost like a muscle, making it harder for the disease to wear it away. Historically, women haven’t been as well-educated as men.

Exercise protects the brain from Alzheimer’s, and studies have shown that at least in the past, women haven’t been as physically active over the course of their lives as men are.

Even surgery is riskier for women.

A little confusion can be normal after general anesthesia, and most people recover from the experience with no lasting problems. But some people never quite recover, and older adults are known to be particularly vulnerable to long-term effects after surgery.

Researchers at Oregon Health & Science University found that men and women who’d been put to sleep for surgery did worse on tests of thinking and memory compared to similar adults who didn’t have surgery. But the declines were bigger and more rapid for women. Women also had more brain shrinkage on MRI scans after anesthesia than men did.

The more procedures a person had, the bigger the brain problems after surgery. And it didn’t seem to matter what anesthesia drug doctors used.

Hormones: Help or Harm?

Another major puzzle about Alzheimer's has been the role of hormones, and whetherhormone replacement therapy hurts or helps a woman’s memory as she ages.

Estrogen plays a large role in brain health. It boosts levels of a chemical that helps nerve cells talk to each other.

It also plays a role in how the brain uses the sugar glucose, its main fuel.

During the period just before menopause, when estrogen levels naturally start to fall, many women complain of problems with foggy thinking and scattered attention.

So doctors wondered whether giving hormones back to women might keep their memory sharp.

But in a large, government-funded study, use of estrogen and progesterone after menopause was found to increase the risk for Alzheimer's and other kinds of dementia. In taking a closer look at the results, though, researchers saw that most of the women in the study were getting hormones when they were well past menopause, long after the body had stopped making them naturally.

That made doctors wonder if giving the hormones closer to the time when the body had stopped making them naturally, around age 50 instead of 65, might make a difference, an idea called “the timing hypothesis.”

Several studies have now checked out that theory and come up empty.

“I’m pretty confident that the data suggest no effect. No evidence of benefit or harm. If a woman is thinking about hormone therapy for whatever reason, there are a lot of things to consider in that decision, but whether or not it’s going to make someone a little smarter or a little duller, I don’t think there’s much of an effect there,” says Victor Henderson, MD, a professor of health research and policy and neurology at Stanford.

But researchers haven’t given up on the hope that estrogen might help protect some women’s brains.

“Now, I think, the question has become more refined over time. Is there even a subset of individuals we should focus on in the critical-window period, and if so, who would that subset be?” says Sarah Janicki, MD, a neurologist at Columbia University.

Personalized medicine may make it possible. Janicki led a study that looked at the genes that tell the body how to make estrogen receptors. Estrogen receptors are docking sites on cells all over the body -- including cells in the brain -- that recognize and respond to estrogen. She found that four gene changes to those receptors were linked to a nearly doubled risk of getting Alzheimer’s.

She says figuring out why could help target women who might benefit or be harmed from hormone therapy. And because men also have estrogen receptors on their brain cells, her research could eventually help them, too.

Menopause isn’t the only time in a woman’s life when her brain goes through big changes.Pregnancy also has an impact.

During pregnancy, a woman’s brain and her baby’s get bombarded with a chemical called allopregnanolone, a brain hormone. It spurs the growth of the baby’s new brain cells and protects them from harm. In Mom, researchers think it may reduce stress.

In mice bred to have a model of Alzheimer’s disease, allopregnanolone sparked the growth of new brain cells and bulked up the brain’s white matter -- the connections that help brain cells communicate. It also reduced the amount of beta-amyloid -- those sticky protein pieces -- that clog the brains of Alzheimer’s patients. And it reversed the memory and thinking changes linked to the disease, so that Alzheimer’s mice treated with allopregnanolone performed the same on memory and thinking tests as normal mice.

It’s important to note that mice aren’t people. Drugs that look promising in animals often do little or nothing for humans.

But Brinton thinks allopregnanolone has promise. She’s testing the drug in people to determine the best dose and to try to get some clues about which patients could benefit from the medication. She won’t know if it helps their memory or thinking for 2 to 3 more years, she says.

Another drug that has shown promise, at least for some patients, is leuprolide, or Lupron. It’s already FDA-approved to treat endometriosis and shrink uterine fibroids.

In one study of more than 100 women with Alzheimer’s, those who took a weekly injection of the drug, along with the Alzheimer’s medication Aricept, saw almost no changes in their memory over the course of a year compared to women who took Aricept alone.

Lupron helps lower levels of follicle-stimulating hormone and luteinizing hormone, chemical signals that surge during menopause and stay high.

Craig Atwood, PhD, an associate professor of geriatrics at the University of Wisconsin School of Medicine, says the treatment helps the brain because it brings haywire hormones back into balance.

Atwood says they are looking at whether the elevated hormones are driving Alzheimer’s disease. Suppressing them may prevent women from aging as rapidly.

But he admits that’s just a guess. Right now, they really don’t understand how the drug might be working or what it might be doing in combination with Aricept.

Atwood and his co-researchers hope to raise more money for a larger clinical trial, one that would test the treatment in men and women.

Families Wait, and Hope

While science churns slowly on, Audrey Schafferman’s family is still struggling to cope without her.

When Audrey was 17, she married a man named Dennis Rose. After each child and grandchild was born, Audrey would proudly say, “It looks like the Roses!”

After Audrey’s death in 2007, Jaime Stone and some of her other grandchildren formed a team to raise money for research into the disease. They walk under the name Audrey’s Little Roses in the annual Walk to End Alzheimer’s, sponsored by the Alzheimer’s Association.

It’s the best way they know to honor the matriarch who took so much with her when she left them.

“We used to be a really, really, really close family. But here in the last couple of years, nobody really wants to get together,” Stone says.

Her grandmother, she says, was the glue that held them all together. “It’s been difficult.”

5 Surprising Alzheimer's Triggers

By: Leah Zerbe for RodaleWellness.com

Whether you're struggling with Alzheimer's yourself or watching a loved one live with it, there is no debating it's an awful disease. And as more researchers are tracking possible triggers of the disease, they're coming across more data connecting everyday exposures to an increased risk.

While no study has yet to definitively say, "Yes, this is what causes Alzheimer's," these 5 things are believed to play a role and should be avoided.

1. Negative Thoughts-Your psyche likely plays a role in Alzheimer's, according to Yale researchers. Negative beliefs about aging, including thoughts that old people are "decrepit," can spark brain changes linked to Alzheimer's disease. 

"We believe it is the stress generated by the negative beliefs about aging that individuals sometimes internalize from society that can result in pathological brain changes," says study author Becca Levy, PhD, an associate professor of public health and psychology at the Yale School of Public Health. "Although the findings are concerning, it is encouraging to realize that these negative beliefs about aging can be mitigated, and positive beliefs about aging can be reinforced, so that the adverse impact is not inevitable." 

2. Lead-Lead isn't just a threat to children. A 2009 study found that adults with high blood levels of lead face a higher risk of dementia. 

Among those who had higher-than-average lead levels, 21% had scores that indicated mild cognitive impairment. Also, lead levels tended to be higher in people who suffered from high blood pressure, itself a risk factor for dementia. Previous research suggests high levels of lead in older adults raise their risk for cardiovascular disease.

In addition to raising blood pressure, lead can cause oxidative stress on the brain and increase inflammation in the body.

To avoid lead exposure, have the interior and exterior paint in your home tested for lead if you live in a pre-1978 house and say no to vinyl products (including purses—yellow ones often test especially high in lead).

Eating green, blue, and red fruits and veggies, which are high in antioxidants, can help mitigate some of the oxidative stress caused by heavy metals.

3. Common Meds-Common medications, ranging from antidepressants to over-the-counter antihistamines, have been linked to dementia and Alzheimer's disease, according to recent research published in the journal JAMA Internal Medicine.

The drugs in question are anticholinergic medications. These drugs include nonprescription diphenhydramine (brand name Benadryl), tricyclic antidepressants like doxepin (Sinequan), first-generation antihistamines like chlorpheniramine (Chlor-Trimeton), and antimuscarinics for bladder control like oxybutynin (Ditropan).

The researchers found that these effects are dose dependent (the more anticholinergic medication you take, the higher your risk for developing dementia), but the findings also suggest that the effects may not be reversible, even after you discontinue use of the drug. 

4. DDT-Higher blood levels of a breakdown product of the nasty insecticide DDT, called DDE, seemed to fuel Alzheimer's disease, according to a 2014 study published in JAMA Neurology.

If further research upholds those findings, it could mean that testing for DDE levels in the body could lead to earlier diagnosis, which has been shown to help ease symptoms of Alzheimer's.

DDT has been banned in the US since 1972, but it's still used elsewhere, and DDE and other breakdown products can enter the environment from waste sites. The Centers for Disease Control and Prevention notes the largest amount of DDT in a person's diet comes from meat, poultry, dairy products, and fish, including sport fish.

5. Depression-There's no denying that our minds and bodies are connected, even when it comes to Alzheimer's disease and dementia. A landmark 2010 study published in Neurologydiscovered a 50% increase in the risk of developing dementia with each 10-point increase in score on depression tests administered at the start of the study.

The risks were similar for Alzheimer's disease, for which there was a 40% increase in risk for each 10-point increase in depression score. For both dementia and Alzheimer's disease, depressed adults were 1.5 times more likely to develop one of the two diseases than nondepressed adults were.

What Helps?

Some lifestyle changes may help stave off the brain disease. Aerobic exercise has been shown to delay or maybe even prevent Alzheimer's in people facing the highest risk of developing it. And in 2015, research published by the Alzheimer's Association found you can lower your risk of Alzheimer's 53%.