Mechanisms underlying elevated systolic blood pressure differ with adiposity in young adults: The Enigma Study

Abstract

The positive association between adiposity and hypertension is well recognized. However, not all overweight individuals have elevated blood pressure (BP). Moreover, different factors may be associated with high BP in normal-weight versus overweight individuals. The aim of the current study was to examine the influence of adiposity on the relationship between systolic BP (SBP) and underlying haemodynamic mechanisms in young adults. Data from 2502 subjects were available from The Enigma Study. Detailed demographic, biochemical and haemodynamic data were obtained in all individuals. Data were analyzed between lower and upper tertiles of body mass index (BMI) and SBP, separately for each gender. In normal-weight individuals, cardiac output (CO) was elevated in those with higher SBP, independently of body size. Moreover, higher CO was associated with an increased stroke volume in males (p<0.001), but an increased heart rate in females (p=0.002). In contrast, in overweight individuals, peripheral vascular resistance (PVR) was elevated in males with higher SBP (p=0.02) and those with lower SBP had the lowest PVR of all groups. In linear regression analyses, there was a stronger association between SBP and CO in normal-weight individuals, but a stronger association between SBP and PVR in overweight individuals. Different haemodynamic mechanisms are associated with elevated SBP in young adults, depending on body size and gender. These data suggest the need for differential approaches to the identification and management of young adults with elevated BP.