BLOOD PRESSURE MEDIATES THE RELATION BETWEEN BODY MASS INDEX AND TARGET ORGAN DAMAGE

Objective: The aim of this study was to examine the relation between body mass index (BMI) and target organ damage (TOD) and the mediating role of blood pressure (BP). Design and method: This study is a cross-sectional analysis of retrospective data from 2,555 adults (52.0% women) who visited the Outpatient Hypertension Unit and with valid measures on weight, height, 24-hour ambulatory BP monitoring, echocardiography, carotid ultrasonography and blood creatinine levels. Patients were categorized according to BMI values as normal weight (<25 kg/m2), overweight (25-29.9 kg/m2) or obesity (>=30 kg/m2). The intima-media thickness (IMT) of the common (CCA) and the internal (ICA) carotid artery, left ventricular mass (LVM), LVM index (LVMI) and estimated glomerular filtration rate (eGFR) were estimated and used as TOD indices. The association between BMI and TOD was examined using univariate and multivariate linear regression models, while structural equation modeling (SEM) was used for mediation analysis. Results: BMI was significantly associated to all blood pressure measurements and CCA- IMT, ICA-IMT, LVM and LVMI (p< 0.05) but not to GFR (p< 0.05). The mediation analysis showed that both office and 24 ambulatory systolic BP partially mediated the relationship between BMI and CCA -IMT, LVM, and LVMI (p< 0.05), while a complete mediation was found for the association between BMI and ICA-IMT (p<0.05). Systolic BP mediated >27% and >30% of the relationship between BMI and CCA-IMT and ICA-IMT, respectively. Conclusions: These results of this study indicate that body mass index is associated with indices of asymptomatic cardiac remodeling and vascular atherosclerosis, with systolic BP playing a key mediating role in these relationships