Two studies published Aug. 21 in JAMA highlighted the link between heart and brain health. One found older individuals who met fewer metrics for ideal cardiovascular health had an increased risk of dementia, while the other showed that younger adults who didn’t achieve similar standards already had decreased cerebral blood flow and more white matter lesions.
“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,” wrote Jeffrey L. Saver, MD, and Mary Cushman, MD, MSc, in an editorial encompassing both papers.
In the study on the older patients, Cecilia Samieri, PhD, and colleagues followed a cohort of 6,626 French participants with a mean age of 73.7. They categorized patients by the number of healthy lifestyle habits they followed from the American Heart Association (AHA) Life’s Simple 7 list: nonsmoking; normal body weight; regular physical activity; healthy diet including regular consumption of fish, fruits and vegetables; and normal cholesterol, glucose and blood pressure levels.
Over a mean follow-up of 8.5 years, the addition of optimal health metrics incrementally lowered an individual’s risk of dementia by about 10 percent per item.
“The study results support the recent recommendations of the AHA and the American Stroke Association for the promotion of the Life’s Simple 7 tool,” Samieri et al. wrote. “From a pragmatic and public health perspective, promoting change in cardiovascular health metrics from poor to intermediate levels with increasing cardiovascular health scores may be more achievable and is likely to have a greater population-level effect for preventing risk factors associated with dementia and cognitive decline than the much more challenging change from poor to optimal level.”
In the other study, University of Oxford researcher Wilby Williamson, MSc, and colleagues analyzed 125 participants with a mean age of 25. Although they didn’t use the AHA checklist, they assessed a similar range of habits and characteristics important to cardiovascular health. They also performed brain MRI to gain insight into cerebral health.
For each modifiable risk factor categorized as healthy, the individuals showed an incremental increase in vessel density and an average of 1.6 fewer white matter hyperintensity lesions. Greater cerebral blood flow was also correlated with vessel density.
“The distribution of MRI findings observed in the current study raises the potential that some individuals may be starting to diverge to different risk trajectories for brain vascular health in early adulthood,” Williamson et al. wrote. “Furthermore, levels of cerebral blood flow associated with an increased risk of dementia are evident in some young adults.”
Both studies were observational, so they could draw associations but not prove causation. Also, Samieri’s group noted cardiovascular measurements were assessed only at baseline, and changes in those metrics throughout the study period may have influenced outcomes.
Still, Saver and Cushman said in their editorial that both studies offer important insights on the heart-brain connection. The subtle brain changes in young individuals who didn’t have heart-healthy habits “may portend more substantial abnormalities later in life,” they wrote.
“These findings further emphasize the importance of both primordial prevention (averting development of cardiovascular risk factors in the first place) and primary prevention (modifying adverse risk factors once present),” Saver and Cushman noted.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.