As you may have read in our blog post this past February, there is a connection between hearing loss and heart health. (That post can be found by clicking here.) And now a study coming out of Bordeaux, France concludes that better cardiovascular health is associated with a lower risk for dementia and lower rates of cognitive decline.
Having optimal levels in more measures of cardiovascular health (nonsmoking, weight, diet, physical activity, cholesterol, blood glucose and blood pressure) for older adults was associated with lower risk for dementia. This observational study included 6,626 adults in France 65 or older. A lower risk for dementia and lower rates of cognitive decline were associated with each additional metric at the recommended optimal level based on an American Heart Association seven-item checklist aimed at preventing cardiovascular disease.
Cardiovascular health at young and old ages showed ties to better brain function, according to two reports.
Optimal scores on an American Heart Association (AHA) seven-item checklist were linked to a lower risk of dementia, a longitudinal study of nearly 7,000 older adults in France found.
And an observational assessment of 125 young adults in Oxford, England, demonstrated that better cardiovascular metrics were associated with higher cerebral vessel density and caliber, higher cerebral blood flow, and fewer white matter hyperintensities.
Previous analyses have examined links between cognitive outcomes and cardiovascular risk factors mostly in middle age, not earlier or later in the life span, noted Jeffrey L. Saver, MD, of the University of California Los Angeles, and Mary Cushman, MD, MSc, of the University of Vermont in Burlington.
Earlier investigations also “more often focused on the deleterious associations of moderate or severe cardiovascular risk factors with cognitive outcomes rather than the advantageous associations of attaining optimal status for each cardiovascular health factor; i.e., ideal cardiovascular health,” they wrote in an editorial accompanying the two studies in JAMA.
Among older adults in France, additional improvements in cardiovascular health score were associated with lower risks for dementia and lower rates of cognitive decline, reported Cecilia Samieri, PhD, of the Université de Bordeaux, and co-authors.
“Each additional favorable health factor or behavior was associated with a 10% lower risk to develop dementia in the following decade,” Samieri told MedPage Today.
In the Three-City Study, 6,626 people ages 65 or older from Bordeaux, Dijon, and Montpellier who did not have a history of cardiovascular diseases or dementia at baseline underwent in-person neuropsychological testing from 1999 to 2016 and systematic detection of incident dementia until July 2016.
The researchers assessed participants’ adherence to the AHA Life’s Simple 7 metrics at baseline. Each item was scored as 0 (poor), 1 (intermediate), or 2 (optimal):
- Nonsmoker for more than 12 months
- Body mass index <25
- Regular physical activity
- Eating fish twice a week or more, and fruits and vegetables daily
- Untreated total cholesterol <200 mg/dL
- Untreated fasting glucose <100 mg/dL
- Untreated blood pressure <120/80 mm Hg
Participants had a mean age of 74 at baseline and 63% were women. At baseline, 36.5% of participants had 0 to 2 metrics at optimal levels, and 6.5% had 5 to 7 optimal metrics.
For participants with 0 to 2 optimal metrics, the incidence rate of dementia per 100 person-years over an average follow-up period of 8.5 years was 1.56. For individuals with 3 to 4 optimal metrics, it was 1.23; for those with 5 to 7 optimal metrics, it was 0.83.
In multivariable models, the risk of dementia decreased linearly with both increasing number of metrics at the recommended optimal level (HR 0.90 per each additional metric) and increasing global cardiovascular health score (HR 0.92 per 1-point increase).
The researchers used composite scores of global cognition and memory to determine cognitive decline. In standard units, with values indicating distance from population means (0 equal to the mean, and +1 equal to 1 SD above the mean), the estimated change in cognitive score for each additional metric at the optimal level was 0.031 standard units at inclusion, 0.068 at year 6, and 0.072 at year 12.
Optimal cardiovascular health in 125 young adults in England was associated with more robust cerebral perfusion and fewer subclinical lesions in brain white matter, reported Paul Leeson, PhD, of the University of Oxford, and colleagues.
Examining eight modifiable cardiovascular risk factors, the researchers assigned a value of 1 for each item at the recommended level:
- Body mass index <25
- Highest tertile of cardiovascular fitness and/or physical activity
- Alcohol consumption <8 drinks/week
- Nonsmoker for more than 6 months
- Blood pressure on awake ambulatory monitoring <130/80 mm Hg
- Non-hypertensive diastolic response to exercise (peak diastolic blood pressure <90 mm Hg)
- Total cholesterol <200 mg/dL
- Fasting glucose <100 mg/dL
In this analysis, the mean age was 25; 49% were women, and participants had an average of 6.0 modifiable cardiovascular risk factors at recommended levels.
Cardiovascular factors were correlated with cerebrovascular morphology and white matter hyperintensities in multivariable models. For each additional risk factor at the recommended level, vessel density was greater by 0.3 vessels/cm3, vessel caliber was greater by 8 μm, and white matter hyperintensity lesions were fewer by 1.6 lesions.
The researchers also examined cerebral blood flow in 52 participants using vessel-encoded arterial spin labeling. Cerebral blood flow varied with vessel density and was 2.5 mL/100 g/min higher for each healthier risk factor.
Both this study and the Three-City Study of older adults in France were observational, so they indicate association, not causation, Saver and Cushman noted. And in both studies, unmeasured and residual confounding may exist.
But with these caveats, these studies convey an immediate message to clinicians, policymakers, and patients, they said: “Available evidence indicates that to achieve 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.”
In the Three-City Study, even subtle changes decreased dementia risk, Samieri pointed out.
“From a pragmatic and public health perspective, promoting change in cardiovascular health from poor to intermediate levels may be more achievable and have a greater population-level effect than the more challenging change from poor to optimal levels,” she said.
“These results offer new insights on the way to formulate recommendations for dementia prevention which may be implemented at both collective and individual levels.”
We hope you took the time to read both of our blog posts (the one linked in the first paragraph, and this one!) We look forward, every week, to providing information that helps you to navigate through the world of hearing loss, to offer insight into how hearing is connected to myriad other health concerns, and to help raise awareness about hearing health and ways to manage hearing loss.
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