Relationship between Adiposity, Blood Pressure, Cardiac Autonomic Function and Arterial Stiffness in Young Healthy Individuals.

Abstract

The precise mechanism linking overweight/obesity with hypertension remains unclear. The present study was conducted (1) to evaluate the impact of adiposity on cardiac autonomic nervous system (ANS) activity and arterial health and (2) to determine the relationship between adiposity, cardiac ANS, arterial stiffness and blood pressure (BP). Methods: A cross-sectional study was conducted on 48 young healthy subjects with overweight/obesity (OW group, n=24) and normal weight (NW group, n=24) with age ranging between 18-24 years. Blood pressure, cardiac ANS and arterial health were evaluated. Heart rate variability (LF: low frequency; HF: high frequency; and LF/HF ratio) was assessed as an index of cardiac ANS function. Pulse wave velocity (brachial-ankle, carotid-femoral, heart-ankle, heart-brachial), aortic augmentation index, arterial stiffness index were measured as an indices of arterial stiffness. Results: LF and LF/HF ratio was significantly elevated (p<0.001) while HF was lowered (p<0.001) in obese/overweight subjects when compared to normal subjects. Though not significant but a mean increase in arterial stiffness was found in OW group when compared to NW group participants. Relationship between covariates in all the participants (n=48) is as follows: BMI was significantly correlated with MAP (p=0.034), HR (p=0.048) and LF/HF ratio (p=0.02). While, there was no significant correlation between (1) BMI and arterial stiffness; and (2) cardiac ANS function indices and arterial stiffness. BMI (β=0.288, p=0.023) and arterial stiffness (β=0.516, p<0.001) were the significant determinants of rising BP. MAP (β=0.591, p<0.001) was the significant determinant of the arterial stiffness. Conclusion: A complex relation exists between adiposity, BP, ANS and arterial stiffness. Excess adiposity may modulate sympathovagal balance by increasing sympathetic activity which can enhance the vascular tone and elevate BP. Inturn, increased BP induces stiffening of arteries that may further augment BP.