Background: Elevated cardiovascular disease risk factor burden is a recognized contributor to poorer cognitive function; however, the physiological mechanisms underlying this association are not well understood. We sought to assess the potential mediation effect of left ventricular (LV) remodeling on the association between lifetime systolic blood pressure and cognitive function in a community-based cohort of middle-aged adults.
Methods: Nine hundred sixty participants of the Bogalusa Heart Study (59.2% women, 33.8% black, aged 48.4±5.1 years) received 2-dimensional echocardiography to quantify relative wall thickness, LV mass, and diastolic and systolic LV function; and a standardized neurocognitive battery to assess memory, executive functioning, and language processing. Multivariable linear regression assessed the association of cardiac structure and function with a global composite cognitive function score, adjusting for traditional cardiovascular disease risk factors. Mediation analysis assessed the effect of LV mass index on the association between lifetime systolic blood pressure burden and cognitive function.
Results: There were 233 (24.3%) and 136 (14.2%) individuals with concentric LV remodeling and concentric LV hypertrophy, respectively. Each g/m2.7 increment in LV mass index was associated with a 0.03 standardized unit decrement in global cognitive function (P=0.03). Individuals with concentric LV remodeling and isolated diastolic dysfunction had the poorest cognitive function, and a greater ratio between early mitral inflow velocity and early diastolic mitral annular velocity (E/e') was associated with poorer cognitive function, even after adjustment for LV mass index (B=-0.12; P=0.03). A total of 18.8% of the association between lifetime systolic blood pressure burden and midlife cognitive function was accounted for by LV mass index.
Conclusions: Cardiac remodeling partially mediates the association between lifespan systolic blood pressure burden and adult cognition in individuals without dementia or clinical cardiovascular disease. Slowing or reversing the progression of cardiac remodeling in middle-age may be a novel therapeutic approach to prevent cognitive decline.
Keywords: dementia; echocardiography; epidemiology; hypertension; ventricular remodeling.