Cross‐sectional relations of subclinical cardiovascular disease to AD blood biomarkers in cognitively intact older adults

Abstract

AbstractBackgroundSubclinical cardiovascular disease (CVD) is a key, early step in the development of frank CVD. Generally characterized by an age‐related increase in atherosclerosis and arterial stiffness, and/or reduced endothelial function, emerging evidence suggests subclinical CVD confers risk for Alzheimer’s disease and related dementias (ADRD) well before the onset of frank CVD. However, despite increasing recognition of the utility of blood biomarkers for understanding the pathophysiological events and progression of AD, little research has examined the association between markers of subclinical CVD and AD blood biomarkers. Thus, we sought to examine these associations in a sample of cognitively intact older adults enrolled in the Healthy Heart & Mind Study.MethodParticipants were 34% male and 41.7% African American with a mean age of 68.43y. Participants completed a health and medication screening, a battery of cognitive tests, a psychosocial assessment, a fasting blood draw, vascular testing (including assessment of carotid intimal‐media thickening (IMT), pulse wave velocity (PWV), and brachial artery flow‐mediated dilation (FMD), and structural brain MRI. Serum Ab1‐40 and Ab1‐42 (and ratio) were available for 99 participants at the time of this analysis.ResultBivariate correlation results showed a significant, positive association between % FMD change and Ab1‐40 only (p<.05). Ordinary least squares regression was run to further examine this association adjusting for the following potential confounding variables: age, gender, education, depression, and mean arterial BP. Results showed the significant, positive association between % FMD change and Ab1‐40 persisted after adjustment (p<.05).ConclusionFindings showed that worse endothelial function may be associated with lower Ab1‐40 in healthy older adults. While some research illustrates Ab1‐40 is reduced in AD, other research suggests increased levels are associated with vascular conditions such as hypertension, ischemic heart disease, and white matter lesions. Thus, our findings suggest a need to further examine the association between endothelial function and AD blood biomarkers to confirm the directionality of the relationship. Longitudinal research is also needed to examine the association over time.