Between the head and the heart: Cardiovascular risk factors and brain structure and cognitive function.

摘要

There is growing appreciation for the relationship between cardiovascular health and brain health. Ischemic heart disease, stroke, diabetes, and hypertension rank in the top 10 leading causes of death in the United States and worldwide. The high prevalence of these chronic diseases combined with a growing aged population suggest the global prevalence of dementia will more than triple by the year 2050, relative to the 2010 prevalence. The objective of this thesis was to address gaps in our current understanding of the relationship between cardiovascular health and brain health, presented in three manuscripts.;In the first manuscript we assessed rate of annual cognitive decline in selected samples of elderly participants (mean age 71 years) in the Chicago Health and Aging Project (CHAP) who developed diabetes (n=405) and hypertension (n=837) between 1993 and 2012. We quantified annual decline in score for four neurocognitive tests during the period before and after the development of these conditions. Individuals who developed diabetes or hypertension experienced 50% to 60% greater rate of annual cognitive decline for neurocognitive tests assessing domains of general orientation and cognitive processing in the period following ascertainment relative to the period prior to ascertainment.;The second manuscript assessed the association between cognitive function and brain structure in middle adulthood and the development of diabetes in later adulthood in the Atherosclerosis Risk in Communities (ARIC) study (45 to 64 years of age at enrollment). In the 10,819 individuals with cognitive assessment at ARIC visit 2, we identified 3,200 incident cases of diabetes over a median follow-up time of 19 years (30% cumulative incidence). Over a median of 14 years of follow-up 373 of the 1,350 participants who underwent MRI developed diabetes (28% cumulative incidence). We found that measures of cognitive function and MRI indicators of subclinical cerebrovascular disease were weakly and inconsistently associated with increased risk for diabetes.;Our final manuscript explored the association between cardiovascular health status during young adulthood, defined by the American Heart Association Life's Simple 7 metric, and measures of brain structure in middle adulthood in the Coronary Artery Risk Development in Young Adults (CARDIA) study. CARDIA participants were 18 to 30 years of age at enrollment and 43 to 55 years of age at the time of MRI. We quantified normal tissue volume of the total brain, gray, and white matter and abnormal tissue volume of white matter according to cardiovascular health score. We observed ideal levels of cardiovascular health throughout young adulthood was not consistently associated with differences in brain structure in middle age.;These findings suggest individuals who develop diabetes and hypertension experience changes in cognitive function in the areas of general orientation and processing speed, cognitive function and brain structure in midlife is not foretelling of risk for diabetes in older age, and that cardiovascular health during young adulthood is not associated with differences in brain structure in middle adulthood, but caution that differences in brain structure at this age are difficult to detect and that changes in brain structure were not assessed.