8 Dementia Risk Factors

by Anne Harding for HealthDay:

Depression and obesity can increase your risk, but there are still ways to keep your brain healthy as you age.

Age is the single biggest risk factor for dementia. Once you hit age 65, your risk of developing Alzheimer's disease doubles every five years, according to the Centres for Disease Control and Prevention. You can't hold back the clock, but there are many other things you can do to keep your brain healthy as you get older.

Brain cell degeneration — like that seen in Alzheimer's disease — is a key factor in the development of dementia in most people, but changes in the tiny blood vessels responsible for supplying the brain with oxygen and glucose are also important, says Mustafa Husain, MD, vice chair in the department of psychiatry and behavioral sciences and chief of geriatrics at Duke University School of Medicine in Durham, North Carolina. “Most microvascular changes can be related to chronic medical risk factors, which can be addressed,” Dr. Husain says.

“Very much of what applies to prevention and good healthy habits in general applies also to the prevention of dementia,” says Gisele Wolf-Klein, MD, a professor of medicine at Hofstra Medical School and director of geriatric education for the North Shore-LIJ Health System in New York.Here are eight treatable, and sometimes preventable, health conditions and risk factors that can increase your dementia risk, and what you can do about them.1. Cardiovascular disease. Experts on the aging brain now agree that while Alzheimer's disease is the most common form of dementia — there are currently five million people with the disease in the United States — heart and blood vessel disease can accelerate the development of Alzheimer's.“Optimizing cardiovascular health is important to prevent vascular events like heart attack and stroke, but also for maintaining optimal brain health and reducing cognitive decline,” says Deborah Levine, MD, an internist and neurologist at the University of Michigan in Ann Arbor.

Steps you can take to protect your brain — and your heart — include:

• keeping your blood pressure under control
• being physically active
• eating a Mediterranean diet rich in fruits, veggies, nuts, healthy oils, and lean protein, while limiting red meat

One study found that the more closely people stuck to a Mediterranean diet — which is known to be the heart-healthiest eating pattern — the slower their cognitive decline and the lower their Alzheimer's risk.You don't have to throw yourself into a strenuous exercise regimen to stave off dementia — studies show that just walking more than a couple of blocks a day will reduce dementia risk, according to Dr. Wolf-Klein.And while keeping blood pressure under control is important, overtreating high blood pressure can be just as harmful as undertreating it, according to Dr. Levine. When blood pressure is too low, she explains, it's harder for our bodies to supply the brain with blood.2. Diabetes. Middle-aged people with diabetes have a steeper decline in their mental function over time than their non-diabetic peers. The worse their blood sugar control, the sharper the drop in mental capacity, according to a large 2014 study published in the Annals of Internal Medicine.

So if you have diabetes, keeping your blood sugar under good control long-term through diet and exercise — and medication if you need it — is essential for maintaining brain health.

But because sugar fuels the brain, overtreatment of diabetes can be damaging, too. “Research suggests that episodes of low blood pressure and low sugar from overtreatment of high blood pressure and diabetes is significantly associated with cognitive decline, particularly in the elderly, and in fact episodes of hypoglycemia increase the risk of developing dementia,” Levine says.3. Depression. Depression and dementia have a complex, intertwined relationship. Depression can be an early sign of Alzheimer's, while symptoms of depression like apathy and difficulty concentrating can mimic dementia.People who are depressed often withdraw from social contact, which can accelerate mental deterioration, Wolf-Klein points out. “Isolation that is the result of depression can be very detrimental to the health of the brain,” she says.In fact, one study found that depression doubled dementia risk. Being depressed and having a stroke increased dementia risk more than five-fold. Furthermore, people with depression who got a new diagnosis of high blood pressure were at triple the risk of dementia.

Fortunately, many of the things that keep depression at bay — socializing with friends and family, and pursuing hobbies, and being physically active — also help keep mental function sharp, Dr. Husain says.

4. Head injury. Kids aren't the only ones who should be protecting their brains by wearing a helmet while biking, skiing, or engaging in other risky activities. Head injury may be even riskier for aging adults, a 2014 study in JAMA Neurology suggests. People aged 55 and older who sustained traumatic brain injury were at significantly increased risk of developing dementia, while even mild brain injury increased dementia risk in the 65 and older group.But there's also evidence that cognitive reserve — think of it as extra mental strength and flexibility — helps protect people from accelerated mental decline after brain injury. Higher IQ, higher levels of educational and occupational attainment, engagement in leisure activities, and strong social networks can all help build cognitive reserve, according to Columbia University researchers.5. Sleep problems. Getting enough rest is a challenge for many of us, especially as we age, but evidence is mounting that it's crucial for maintaining a healthy brain. And sleep disordered breathing — in which a person wakes up several times during the night, gasping for breath — may be especially harmful to cognitive function. Several studies have linked this condition, also known as sleep apnea, in older people to increased mental impairment.

Other research suggests that the brain washes out harmful proteins and other potentially damaging waste products during sleep. Investigators first reported on this cleaning mechanism — which they dubbed the glymphatic system — in mice. While it's tougher to peer inside the human brain, continuing research by these investigators is suggesting that people have a similar plumbing system that flushes out brain waste while we sleep — yet another reason to aim for a good night's rest.

6. Midlife obesity. Studies of the relationship between obesity and cognitive function have had mixed results, but there is evidence that excess weight can boost the risk of future mental decline. A 2014 study in more than 4,000 twin pairs found that being obese in one's forties quadrupled future dementia risk, while being overweight nearly doubled it. Another study found that people who were obese and had metabolic abnormalities at the study's outset, such as high blood pressure or high cholesterol, had the sharpest decline in cognitive function.“There is evidence that obesity, extra weight, can lead to increased chances of developing dementia,” Wolf-Klein says. “We have to continually remind ourselves and our children that good weight control is certainly a good approach to better life ... and diminishing the possibility of so many chronic conditions, including dementia.”7. Smoking cigarettes. If you smoke cigarettes, you're 30 percent more likely to develop dementia, according to an analysis of 37 different studies including close to a million people. The research review also found that the more you smoke, the higher your risk. But here's the good news: this study also showed that if you quit, your dementia risk is the same as if you'd never smoked.

8. Heavy alcohol consumption. Most studies have not found a relationship between light-to-moderate alcohol consumption — generally defined as one drink a day for women, and two per day for men — and dementia. A few have even suggested that light drinking can protect the brain. But heavy drinking and binge drinking are both linked to stroke and dementia. In fact, people who reported consuming more than five bottles of beer in one sitting, or one bottle of wine, in midlife were three times as likely as non-binge drinkers to ahve dementia by age 65.

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