Norton Gavin R, Majane Olebogeng Hi, Libhaber Elena, Maseko Muzi J, Makaula Siyanda, Libhaber Carlos, Woodiwiss Angela J
University of the Witwatersrand, Johannesburg, South Africa.
J Hypertens. 2009 Sep;27(9):1873-83. doi: 10.1097/HJH.0b013e32832dca53.
To determine whether blood pressure (BP)-LVM relationships depend in-part on the influence of an excess adiposity and whether this translates into a greater effect of hypertension on LVM in obese as compared with lean people.
In 399 randomly recruited participants from a general population with a high prevalence of excess adiposity ( approximately 68%), we assessed whether the relationships between conventional blood pressure (BP) and LVM indexed for height (LVMI) (determined from echocardiography) are influenced by adiposity. We confirmed these outcomes using 24-h ambulatory measurements in 297 participants; and carotid-femoral pulse wave velocity (PWV) (applanation tonometry) in 328 participants and from plasma leptin concentrations, we assessed whether leptin could mediate this effect.
After adjustments for appropriate confounders, including the individual terms for adiposity and BP, interactions between adiposity indices (either waist circumference or the mean of subscapular and triceps skin-fold thickness) and either conventional systolic BP (SBP), 24-h SBP, PWV, conventional pulse pressure (PP), or 24-h PP were independently associated with LVMI (P < 0.001 for interactions). The adiposity index-haemodynamic interaction translated into a steeper slope of the BP-LVMI and PWV-LVMI relations in obese as compared with lean participants. Every one SD increase in conventional SBP ( approximately 22 mmHg) was associated with a 1.61 g/m increase in LVMI in participants with a normal waist circumference, in comparison to a 5.24 g/m increase in LVMI in those with an increased waist circumference (P < 0.0001). Furthermore, the adiposity index-haemodynamic interaction resulted in an increased LVMI in never-treated hypertensives with central obesity (LVMI, normotensives = 45.6 g/m, hypertensives = 51.0 g/m, P < 0.02), but not in participants with a normal waist circumference (LVMI, normotensives = 43.4 g/m, hypertensives = 45.0 g/m). Significant plasma leptin concentration-haemodynamic interactions were also associated with LVMI independent of confounders and adiposity indices, an effect that translated into a steeper slope of the haemodynamic factor-LVMI relations in participants with a plasma leptin concentration above as compared with those below the median for the group.
Adiposity-induced increases in LVM reflect an enhanced effect of BP on LV growth, an effect that may be mediated by leptin. This translates into an impact of never-treated hypertension on LVMI in centrally obese, but not in lean people in groups of African descent in South Africa.
确定血压（BP）与左心室质量（LVM）的关系是否部分取决于肥胖过多的影响，以及与瘦人相比，这是否会使高血压对肥胖者左心室质量产生更大影响。
在399名从肥胖发生率较高（约68%）的普通人群中随机招募的参与者中，我们评估了传统血压（BP）与根据身高校正的左心室质量指数（LVMI）（通过超声心动图测定）之间的关系是否受肥胖影响。我们在297名参与者中采用24小时动态测量来确认这些结果；在328名参与者中采用颈动脉 - 股动脉脉搏波速度（PWV）（压平式眼压计测量），并根据血浆瘦素浓度，评估瘦素是否能介导这种效应。
在对包括肥胖和血压的个体指标等适当混杂因素进行调整后，肥胖指数（腰围或肩胛下和肱三头肌皮肤褶皱厚度的平均值）与传统收缩压（SBP）、24小时SBP、PWV、传统脉压（PP）或24小时PP之间的相互作用与LVMI独立相关（相互作用P<0.001）。与瘦参与者相比，肥胖指数 - 血流动力学相互作用导致肥胖者BP - LVMI和PWV - LVMI关系的斜率更陡。腰围正常的参与者中，传统SBP每增加一个标准差（约22 mmHg），LVMI增加1.61 g/m，而腰围增加者中LVMI增加5.24 g/m（P<0.0001）。此外，肥胖指数 - 血流动力学相互作用导致从未接受治疗的中心性肥胖高血压患者的LVMI增加（LVMI，血压正常者 = 45.6 g/m，高血压患者 = 51.0 g/m，P<0.02），但腰围正常的参与者中未出现这种情况（LVMI，血压正常者 = 43.4 g/m，高血压患者 = 45.0 g/m）。血浆瘦素浓度与血流动力学的显著相互作用也与LVMI独立相关，不受混杂因素和肥胖指数影响，这种效应导致血浆瘦素浓度高于组中位数的参与者中血流动力学因素 - LVMI关系的斜率比低于中位数者更陡。
肥胖引起的LVM增加反映了BP对左心室生长的增强作用，这种作用可能由瘦素介导。这转化为从未接受治疗的高血压对南非非洲裔人群中中心性肥胖者LVMI有影响，但对瘦人无影响。
