Indices of Vascular Stiffness and Wave Reflection in Relation to Body Mass Index or Body Fat in Healthy Subjects

Abstract

1. Obesity appears to influence vascular stiffness, an important cardiovascular risk factor. An accurate picture of arterial stiffness may be obtained when a combination of various techniques is used. 2. The purpose of the present study was to assess whether the body mass index (BMI) and body fat content obtained by bioimpedance were of equal value in estimating the influence of body fatness on various indices of vascular stiffness and wave reflection. 3. A total of 175 healthy subjects was studied. Anthropometric measurements and total body bio-impedance analysis were performed to assess fat mass as a proportion of total body composition. Arterial stiffness and wave reflection were assessed using digital volume pulse analysis and tonometric measurement of the wave reflection indices and central haemodynamics. 4. Significant differences in the stiffness index (SI(DVP); P < 0.0001), peripheral augmentation index (pAI(x); P < 0.0001), central augmentation index (cAI(x); P < 0.0001), peripheral pulse pressure (pPP; P = 0.026) and central pulse pressure (cPP; P < 0.0001) were found when the population examined was divided accordingly to tertile of body fat content. However, subdividing various indices of arterial stiffness according to the tertile of BMI did not reveal any significant differences between groups, except for pPP and cPP. 5. Body fat content was significantly correlated with SI(DVP), pAI(x), cAI(x), pPP and cPP. The BMI correlated weakly with SI(DVP), pPP and cPP. 6. In conclusion, the BMI is not very useful in predicting changes in arterial stiffness and wave reflection due to obesity. However, stiffness and wave reflection indices derived from digital volume pulse analysis, the characteristics of radial and aortic pressure waveforms and peripheral and aortic pulse pressure are all related to body fat content, as estimated by bioimpedance.

Obesity as an independent influential factor for reduced radial arterial wave reflection in a middle-aged Japanese male population

“…These findings suggest that although it does not have a major impact, obesity, including abdominal obesity, is an influential factor for reduced radial arterial wave reflection in a non-hospital-based, middle-aged Japanese male population. A number of studies have shown the relationship of AI to BMI and/ or WC, [14][15][16][17][18][19][20][21][22] but the results are inconclusive. The differences in the characteristics of the study subjects and in the methodology for measuring AI among the studies may have caused these discrepancies.…”

“…AI is well known to be influenced by several hemodynamic and anthropometric parameters such as blood pressure (BP), heart rate and height, 13 but the influence of obesity on AI is still controversial. [14][15][16][17][18][19][20][21][22] Moreover, to our knowledge, no reports have evaluated the association between obesity, including abdominal obesity, and AI in a nonhospital-based, apparently healthy Japanese population. Understanding this association could enable us to more accurately interpret the AI value for each individual in a variety of clinical settings.…”

Effects of resistance exercise training on resting and post-exercise forearm blood flow and wave reflection in overweight and obese women

“…4 Resting forearm blood flow (FBF) 5 and vasodilatory capacity 6 are decreased in overweight and obese adults. Obesity is also associated with increased augmentation index (AIx), 7 a measure of pressure wave reflection that is reduced by vasodilation of muscular arteries. 8 Chronic exercise, in particular, resistance exercise training (RET), has been suggested to improve endothelial function, [9][10][11] by increasing FBF and vasodilatory capacity, which in turn may decrease the AIx.…”

Arterial stiffness, central blood pressure and body size in health and disease

“…To our knowledge, only one previous study has reported associations between measures of body size and fatness with central haemodynamics estimated by radial tonometry in apparently healthy subjects. 24 These investigators showed that both central and brachial pulse pressure significantly increased across tertiles of BMI as well as tertiles of body fat (as a proportion of total body mass) assessed by bioelectrical impedance. Although these data are in alignment with our own, no objective measures of blood biochemistry or clinical characteristics (apart from BP) were presented and the different methods to assess body size (waist circumference compared with body fat by bio-impedance) 24 make it difficult to directly compare findings.…”

“…24 These investigators showed that both central and brachial pulse pressure significantly increased across tertiles of BMI as well as tertiles of body fat (as a proportion of total body mass) assessed by bioelectrical impedance. Although these data are in alignment with our own, no objective measures of blood biochemistry or clinical characteristics (apart from BP) were presented and the different methods to assess body size (waist circumference compared with body fat by bio-impedance) 24 make it difficult to directly compare findings. In an indigenous Australian population with and without type 2 diabetes, Maple-Brown et al 25 noted that several indices of obesity (that is BMI, waist and body weight) were inversely associated with AIx.…”