Metabolic and vascular risk factors are associated with reduced cerebral blood flow and poorer midlife memory performance

Figures

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  Figure 1. A summary of the bivariate correlation coefficients between each of the metabolic and vascular risk factors. Ellipse shapes denote the direction of the correlation and numerical values are also provided in each of the corresponding correlation panels. Red color denotes positive correlation, while blue denotes negative correlation. BMI, body mass index; waist, waist circumference; SBP, systolic blood pressure; DBP, diastolic blood pressure; GLU, fasting glucose; GLU2HR, oral glucose tolerance test; INS, insulin; HDL, high‐density lipoprotein; LDL, low‐density lipoprotein; TRIG: triglycerides

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  Figure 2. The left panel image shows an axial view of the absolute CBF image for a single participant. The scale bar denotes the CBF level as the image intensity (units: ml/100 g/min). The middle panel shows the corresponding T1‐weighted image. The right panel is the histogram of CBF values across all participants for one ROI (i.e., the left precuneus region). CBF, cerebral blood flow; ROI, regions of interest

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  Figure 3. (a) The PLS model demonstrates there is an association between regional CBF and MVRFs, producing one significant latent variable (permutation‐based p = .005). MVRFs with a partial correlation above zero, based on the error bounds, contribute to the latent variable effect. (b) The color overlay (blue) on the standard brain demonstrates regions that contributed to the latent variable based on the calculated bootstrap ratio (BSR > 2; the size of the color denotes the bootstrap ratio). Given that the PLS was performed on an ROI basis, the corresponding brain locations reflect the approximate neuroanatomical coordinates. CBF, cerebral blood flow; BSR, bootstrapping ratio; PLS, partial least squares; ROI, regions of interest

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  Figure 4. The mediation model tested for direct and indirect associations between the MVRF composite and the RAVLT score. There were significant direct associations between MVRFs and CBF (t = −2.10, p = .03; as expected from PLS), and MVRFs and RAVLT (t = −2.06, p = .03); however, the indirect CBF mediation pathway was not significant. For context, the table shows the correlation between the summary metrics for MVRFs and RAVLT in relation to their factor analysis inputs. CBF, cerebral blood flow; PLS, partial least squares; RAVLT, Rey auditory verbal learning test; MVRFs, metabolic and vascular risk factors