Higher CV health associated with lower risk of dementia and cognitive decline in older adults
Association of Cardiovascular Health Level in Older Age With Cognitive Decline and Incident Dementia
Introduction and methods
Hypertension, dyslipidemia, obesity, and diabetes in midlife have not only been associated with CVD, but also with increased risk of dementia and cognitive decline [1-3]. However, only few studies have assessed the combined effect of risk factors on risk of dementia and cognitive aging, and these studies have mainly focused on lifestyle risk factors [4-5]. The American Heart Association (AHA) developed a 7-item tool, including four health behaviors and three biological measures, to promote CV health, as a prevention strategy in CVD [6-8]. This study investigated the association between CV health level, based on the AHA tool, and risk of dementia and cognitive decline in a large French cohort of older individuals.
This Three-City (3C) Study was a prospective cohort study (1999-2016) and included subjects aged ≥65 years (mean age 73.7 years) from three French cities (Bordeaux [n=2104], Dijon [n=4931], and Montpellier [n=2259]), without CVD or dementia at baseline. Baseline data on AHA metrics were collected by interviews and participants underwent repeated in-person neuropsychological and systemic cognitive detection of incident dementia during a follow-up with a mean of 8.5 years.
CV health level was assessed through the number of AHA Life’s Simple 7 health 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 mmHg [untreated]; score range, 0-7) and a global CV health score, calculated by assigning 0 point for each metric at poor level, 1 point for each metric at intermediate level, and 2 points for each metric at recommended optimal level (total score range, 0-14).
Primary outcomes were dementia, assessed by neuropsychological tests, a neurologist, and an independent committee of neurologists, until consensus was obtained and cognitive decline, which was measured by composite scores of global cognition and memory.
- Compared with the incident rate of dementia of 1.76 (95%CI: 1.38 to 2.15) per 100 person-years among participants with 0 or 1 health metrics at optimal levels, the absolute rate difference per 100 person-years for each additional metric at optimal level were -0.26 (95%CI: -0.48 to -0.04) for 2 metrics, -0.59 (95%CI: -0.80 to -0.38) for 3 metrics, -0.43 (95%CI: -0.65 to -0.21) for 4 metrics, -0.93 (95%CI: -1.18 to -0.68) for 5 metrics, and -0.96 (95%CI: -1.37 to -0.56) for 6 or 7 metrics.
- After multivariable correction, risk of dementia reduced significantly and linearly with both increasing number of metrics and recommended optimal level (HR: 0.90 [95%CI: 0.84-0.97] per each additional metric) and increasing global CV health score (HR: 0.91 [95%CI: 0.89-0.96] per 1-point increase).
- Analyses of cognitive change were consistent with the analysis on dementia. Both increasing number of metrics at optimal level and higher global CV health score were significantly related to a lower rate of decline in global cognition (P=0.002 and P<0.001, respectively) and in memory (P=0.02 and P=0.003, respectively).
This cohort study showed that increased numbers of optimal CV health metrics and higher CV health scores were associated with reduced risk of dementia and lower rate of cognitive decline in older French adults without CV disease, suggesting that promotion of CV health can prevent the development of risk factors associated with cognitive decline and dementia.