• Compared with low cardiovascular health, intermediate and high levels of health were both associated with substantially lower incidence of cognitive impairment, researchers found.
• Note that the lack of a dose-response relationship suggests that it is not necessary to achieve high levels of cardiovascular health to experience lower levels of cognitive impairment.

Better cardiovascular health was associated with a lower likelihood of developing cognitive impairment in both black and white individuals, an analysis of the REGARDS study showed.

Compared with those who had poor cardiovascular health defined by the American Heart Association’s (AHA’s) Life’s Simple 7, the odds of impaired cognition were lower in those with intermediate scores (OR 0.65, 95% CI 0.52-0.81) and high scores (0.63, 95% CI 0.51-0.79), according to Evan Thacker, PhD, of Brigham Young University in Provo, Utah, and colleagues.

The findings were consistent in men and women and across geographical regions, age groups, and levels of education, the researchers reported online in the Journal of the American Heart Association.

“We did not observe a dose-response pattern; people with intermediate and high levels of cardiovascular health had similar incidence of cognitive impairment,” they wrote. “This suggests that even when high cardiovascular health is not achieved, intermediate levels … are preferable to low cardiovascular health.”

“This is an encouraging message for population health promotion,” they added, “because intermediate cardiovascular health is a more realistic target than ideal cardiovascular health for many individuals.”

The Life’s Simple 7 measure — based on four modifiable behavioral characteristics (smoking, diet, physical activity, body mass index) and three modifiable biological characteristics (blood pressure, total cholesterol, and fasting glucose) — was introduced in 2010 as a way “to track health status in relation to a 2020 strategic goal to improve cardiovascular health of Americans,” according to the authors. Prior studies have shown that higher scores are associated with reduced cardiovascular risks.

To explore the relationship between the Life’s Simple 7 variables and cognitive function, Thacker and colleagues examined data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. The current analysis included 17,761 black or white individuals 45 and older (mean age 64) who had normal cognitive function and no history of stroke at baseline.

Each Life’s Simple 7 variable was categorized as ideal (2 points), intermediate (1 point), or poor (0 points), resulting in scores ranging from 0 to 14. Scores of 0 to 6 were considered low, scores of 7 to 8 were considered intermediate, and scores of 9 to 14 were considered high. The average at baseline was 7.5.

According to a three-test measure covering verbal learning, memory, and fluency measured an average of 4 years from baseline, 3.2% of the participants developed cognitive impairment. The rate was 4.6% in those with low Life’s Simple 7 scores and 2.7% and 2.6% in the intermediate and high groups, respectively.

After adjustment for potential confounders, the odds of developing cognitive impairment were lower in the groups with intermediate and high cardiovascular health, with the strongest relationships observed with smoking, body mass index, and fasting glucose.

“We excluded participants who experienced stroke before their follow-up three-test measure of cognitive function,” the authors noted. “Therefore, our results suggest that the mechanism linking cardiovascular health with cognition is something other than clinical stroke. Our findings do not rule out covert or subclinical stroke as a potential mechanism.”

They pointed out that a previous analysis of the CARDIA study, which included young adults ages 18 to 30, showed that better cardiovascular health was associated with better cognitive function 25 years later.

“Taken together,” they wrote, “the findings from REGARDS and CARDIA suggest that both older adult and younger adult populations could be appropriately targeted for lifestyle interventions aimed at reducing risk for cognitive decline.”

The researchers acknowledged some limitations of the analysis, including the nonrandom pattern of missing follow-up data, the possibility of measurement error in the Life’s Simple 7 variables, cognitive function, and other factors, the potential for residual confounding, and the lack of data on cardiovascular health measures over time.

Nevertheless, they wrote, “based on these findings, we hypothesize that the AHA’s strategic efforts to improve cardiovascular health from poor to intermediate or higher levels could lead to reductions in cognitive decline, and we believe further research addressing this hypothesis is warranted.”

From the American Heart Association:

• Vascular Contributions to Cognitive Impairment and Dementia

Primary source: Journal of the American Heart Association