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Having a healthy heart may lower the risk of dementia, study suggests

REUTERS/Lucy Nicholson
Getting regular exercise is one of the seven steps for lowering the risk of cardiovascular disease.

Taking action to lower your risk of heart disease may also help lower your risk of developing dementia, according to a French study published recently in the Journal of the American Medical Association (JAMA).

The study found that older adults who successfully followed seven heart-healthy actions recommended by the American Heart Association (AHA) were significantly less likely to develop dementia in their later years.

And the more of the seven actions they were able to adhere to, the lower their risk.

This study — along with others — suggest that when it comes to achieving a “lifetime of robust brain health free of dementia, it is never too early or too late to strive for attainment of ideal cardiovascular health,” write the authors of an editorial that accompanies the study.

Prior knowledge

Although dementia is a major public health concern, its incidence rate has actually been declining in both the United States and other developed countries in recent decades, background information in the study points out.

Many factors have been cited as possible reasons for the decline, including better education, increased wealth and greater use of anti-inflammatory drugs. But also on that list is improved control of risk factors for cardiovascular diseases (ones involving the heart and blood vessels).

“The recent decline in dementia incidence was preceded by a halving of cardiovascular and cerebrovascular disease incidence over the past 60 years,” the editorial points out.

In the past, most research that has looked at the effects of cardiovascular-disease-related risk factors on dementia has tended to focus on individual lifestyle behaviors. Few studies have investigated the combined effect of the risk factors on the likelihood of developing dementia, however.

Simple seven

The new study attempts to fill that research void. For the study, a team of researchers led by Cecilia Samieri, an epidemiologist at Bordeaux University and INSERM in France, examined whether the AHA’s Life’s Simple 7 metrics, which the association recommends for lowering the risk of cardiovascular disease, had any effect on the risk of dementia.

The seven evidence-based metrics are the following:

  • not smoking
  • having a body mass index (BMI) under 25
  • getting regular exercise
  • having blood pressure under 120/80 mm Hg
  • keeping total cholesterol under 200 mg/dL
  • keeping blood glucose (sugar) under 100 mg/dL
  • eating fish twice a week and fruits and vegetables at least three times a day

The subjects of the study were 6,626 older French adults (mean age: 73.7 years) who were participating in an ongoing research project on aging. Samieri and her colleagues used the health and lifestyle data collected for that project to categorize and score all 6,626 participants on each of the seven AHA metrics. The categories were “optimal” (2 points), “intermediate,” (1 point) and “poor” (0 points).

Not many of the participants had high scores. Only 6.5 percent of them had optimal scores for at least five of the seven categories, while more than a third — 36.4 percent — received optimal scores in two or fewer categories.

The participants were followed for an average of 8.5 years. During that period, 745 of them — or about 11 percent — were diagnosed with dementia.

The study revealed some striking associations between the participants’ metric scores and their risk of developing dementia.

Among those with zero to two optimal metrics at the start of the study, 12.7 percent developed dementia. That compared to 10.7 percent of those with three to four optimal metrics, and 7.9 percent of those with five to all seven.

For each additional metric at the optimal level, the risk of dementia fell by about 10 percent.

It’s never too late

The study is observational, so it can’t prove a connection between fewer cardiovascular risk factors and a lower risk of dementia. It can show only a correlation. Also, the cardiovascular health metrics were evaluated only once, at the start of the study. Some of the participants’ scores might have changed later in the study in ways that could have affected their cognitive health.

In addition, the study’s participants were predominately white, urban and French. The study’s findings, therefore, may not be applicable to other populations.

Still, the findings are not out of line with other research results that have suggested cardiovascular health plays a key role in brain health as we age.

As Samieri told Time magazine reporter Alice Park, the findings are also encouraging, for they for suggest that “it’s never too late” to take steps to prevent dementia.

Nor is it necessary to control all seven metrics for the brain to benefit. “Even if you cannot do all seven, then try to do your best,” Samieri said.

FMI: The study’s abstract can be read at the JAMA website, but the full study is, unfortunately, behind a paywall. You’ll find details about the AHA’s Life’s Simple 7 at that organization’s website.

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