Blood Pressure Partially Mediated the Association of Insulin Resistance and Cerebral Small Vessel Disease: A Community-Based Study.

Background: Insulin resistance as a significant vascular risk factor has been studied in relation to cerebral small vessel disease (SVD). Evidence suggests that insulin resistance might trigger high blood pressure (BP). Therefore, we aimed to investigate whether insulin resistance impacts SVD with a mediating effect of BP in nondiabetic subjects.
Methods and Results: PRECISE (Polyvascular Evaluation for Cognitive Impairment and Vascular Events) study participants underwent brain and vascular imaging techniques and metabolomic risk factors measurements. Insulin resistance was evaluated by the insulin sensitivity index and the Homeostatic Model Assessment for Insulin Resistance based on the standard oral glucose tolerance test. On average, 2752 nondiabetic subjects (47.1% men) aged 60.9 years were included. The multivariable logistic regression model and linear regression model tested the association of insulin resistance with BP components (including systolic BP [SBP], diastolic BP (DBP), and pulse pressure [PP]) and SVD, and of BP components with SVD. In the mediation analysis, SBP, DBP, and PP were found to partially mediate the detrimental effect of insulin resistance (assessed by the insulin sensitivity index) on lacunes (mediation percentage: SBP, 31.15%; DBP, 34.21%; PP, 10.43%), white matter hyperintensity (mediation percentage: SBP, 37.34%; DBP, 44.15%; PP, 9.80%), and SVD total burden (mediation percentage: SBP, 42.07%; DBP, 49.29%; PP, 11.71%) (all P <0.05). The mediation analysis results were not significant when using the Homeostatic Model Assessment for Insulin Resistance to assess insulin resistance.
Conclusions: Higher insulin resistance was associated with SVD in this community-dwelling population. The association of insulin resistance with lacunes, white matter hyperintensity, and SVD total burden was explained in part by BP.
Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03178448.