Association of Cardiovascular Health Level in Older Age With Cognitive Decline and Incident Dementia

Abstract

Importance: Evidence is limited regarding the relation between cardiovascular health level and dementia risk.

Objective: To investigate the association between cardiovascular health level, defined using the 7-item tool from the American Heart Association (AHA), and risk of dementia and cognitive decline in older persons.

Design, setting, and participants: Population-based cohort study of persons aged 65 years or older from Bordeaux, Dijon, and Montpellier, France, without history of cardiovascular diseases or dementia at baseline who underwent repeated in-person neuropsychological testing (January 1999-July 2016) and systematic detection of incident dementia (date of final follow-up, July 26, 2016).

Exposures: The number of the AHA's Life's Simple 7 metrics at recommended optimal level (nonsmoking, body mass index <25, regular physical activity, eating fish twice a week or more and fruits and vegetables at least 3 times a day, cholesterol <200 mg/dL [untreated], fasting glucose <100 mg/dL [untreated], and blood pressure <120/80 mm Hg [untreated]; score range, 0-7) and a global cardiovascular health score (range, 0-14; poor, intermediate, and optimal levels of each metric assigned a value of 0, 1, and 2, respectively).

Main outcomes and measures: Incident dementia validated by an expert committee and change in a composite score of global cognition (in standard units, with values indicating distance from population means, 0 equal to the mean, and +1 and -1 equal to 1 SD above and below the mean).

Results: Among 6626 participants (mean age, 73.7 years; 4200 women [63.4%]), 2412 (36.5%), 3781 (57.1%), and 433 (6.5%) had 0 to 2, 3 to 4, and 5 to 7 health metrics at optimal levels, respectively, at baseline. Over a mean follow-up duration of 8.5 (range, 0.6-16.6) years, 745 participants had incident adjudicated dementia. Compared with the incidence rate of dementia of 1.76 (95% CI, 1.38-2.15) per 100 person-years among those with 0 or 1 health metrics at optimal levels, the absolute differences in incident dementia rates for 2, 3, 4, 5, and 6 to 7 metrics were, respectively, -0.26 (95% CI, -0.48 to -0.04), -0.59 (95% CI, -0.80 to -0.38), -0.43 (95% CI, -0.65 to -0.21), -0.93 (95% CI, -1.18 to -0.68), and -0.96 (95% CI, -1.37 to -0.56) per 100 person-years. In multivariable models, the hazard ratios for dementia were 0.90 (95% CI, 0.84-0.97) per additional optimal metric and 0.92 (95% CI, 0.89-0.96) per additional point on the global score. Furthermore, the gain in global cognition associated with each additional optimal metric at baseline was 0.031 (95% CI, 0.009-0.053) standard units at inclusion, 0.068 (95% CI, 0.045-0.092) units at year 6, and 0.072 (95% CI, 0.042-0.102) units at year 12.

Conclusions and relevance: In this cohort of older adults, increased numbers of optimal cardiovascular health metrics and a higher cardiovascular health score were associated with a lower risk of dementia and lower rates of cognitive decline. These findings may support the promotion of cardiovascular health to prevent risk factors associated with cognitive decline and dementia.

Figure 1.. Flow of Participants Included in the Three-City Study Population

Figure 2.. Mean Trajectories of Change in Global Cognition and Memory Predicted by a Multivariable Linear Mixed Model for a Specific Profile of Covariates, by Increasing Number of Recommended Optimal Cardiovascular Health Metrics and by Higher Total Cardiovascular Health Score

Trajectories of change in global cognition and memory were estimated using linear mixed models among individuals with at least 1 complete battery of cognitive tests across repeated visits for computation of the composite score of global cognition (panels A and B) and of memory (panels C and D). Models considered a nonlinear trajectory with time approximated by natural cubic splines (with corresponding random effects); they also included a cardiovascular health level variable (number of recommended cardiovascular health metrics at optimal level [panels A and C] or higher total cardiovascular health score [panels B and D]) and its interactions with splines functions of time as well as age, study center, educational level, and apolipoprotein E ε4 (APOEε4) carrier status and their interactions with time. Composite scores for global cognition and memory were normalized using latent process mixed modeling and standardized before being entered as dependent variables in mixed models. Data were plotted for a chosen profile of covariates (eg, a man aged 73 years [median baseline age in the sample] from the Bordeaux study center with no higher than primary educational level who does not carry the APOEε4 allele). “Metrics × splines” and “score × splines” refer to the interactions of each cardiovascular health level exposure variable with splines functions of time in the linear mixed models. See Methods section of text for further explanation. Numbers of participants followed up at least to each time point are shown under the x-axes.