Body Mass Index and Blood Pressure Influences on Left Ventricular Mass and Geometry in African Americans

Abstract

Abstract-A unique interaction between the influences of body mass index and blood pressure on left ventricular mass index and geometry may contribute to the higher prevalence of left ventricular hypertrophy in African Americans. This cross-sectional study assessed separate and joint influences of body mass index and blood pressure on left ventricular mass index and geometry in 1729 African American participants of the Atherosclerotic Risk in Communities Study. The association between both left ventricular mass index and relative wall thickness and body mass index in each blood pressure category and between these variables and blood pressure in each body mass index category was assessed adjusting for age, diabetes status, hypertension medication, and smoking status. We found that left ventricular hypertrophy and concentric geometry were highly prevalent and that body mass index and blood pressure were independently associated with left ventricular mass index. The adjusted association between blood pressure and left ventricular mass index was stronger with higher body mass index categories; however, there was no significant interaction suggesting merely an additive relationship (not synergistic/multiplicative as tested for in the interaction analysis). Although relative wall thickness was greater with higher categories of body mass index and blood pressure, the mean difference in relative wall thickness between body mass index and blood pressure categories was not statistically significant. The effect on left ventricular geometry as measured by relative wall thickness supports the theory that there is a pathophysiological component in the mechanism of hypertrophy. Key Words: hypertrophy Ⅲ body mass index Ⅲ blood pressure I ncreased left ventricular mass (LVM) as determined by 2-dimensional M-mode echocardiography is a predictor of cardiovascular morbidity and mortality. 1,2 In the few earlier studies comparing LVM in African Americans to that in whites, results suggest that in African Americans, LVM is increased compared with other ethnic groups at a given blood pressure, representing a potential racial disparity in cardiac adaptation to hypertension. 3,4 Recent studies have indexed LVM by height and/or body surface area and have not reproduced this racial disparity in LVM severity. 5,6 Disparities in left ventricular (LV) wall thickness still persisted in a number of these studies, and LV wall thickness in itself has been associated with cardiovascular mortality. Despite the question of racial differences in the prevalence of left ventricular hypertrophy (LVH) and in the patterns of LV remodeling, risk factors contributing to increased LVM and changes in LV geometry have not been extensively investigated in African Americans but mostly in large, predominantly white population-based cohorts such as Framingham Heart Study. Generalizability of these studies to the black population has not been well defined. 7 This report focuses on an analysis of the independent and combined effects of body mass index (BMI) and bloo...

Childhood Adiposity as a Predictor of Cardiac Mass in Adulthood

“…[13][14][15]18,26 The contemporaneous BMI was also a major determinant of LVM index at the adult age in the present study, as has been shown previously. [27][28][29] In the present study, those who had higher levels of childhood adiposity had larger cardiac size 21 years later, and the cumulative burden of adiposity since childhood increased the risk of cardiac enlargement.…”

“…The adverse effect of elevated blood pressure to increase LVM is well documented, both cross-sectionally and longitudinally, in childhood and in adulthood. [13][14][15][16][17][18]27,28 Taken together, these data, along with intervention studies, 36,37 indicate that obesity and elevated blood pressure are the 2 major determinants acting in concert to develop increased cardiac mass. The observed greater LVM in blacks than in whites has been documented in several studies [15][16][17][18]26,28,38,39 ; however, the racial difference in LVM (Table 1) disappeared when further adjusted for BMI and systolic blood pressure (data not shown).…”

Effect of glycemic control on the progress of left ventricular hypertrophy and diastolic dysfunction in children with type I diabetes mellitus

“…On the other hand, diastolic blood pressure had a significant positive correlation with IVS thickness, systolic blood pressure was the only parameter related to LVEDD (β=0.2, 95% CI: 0.1 -0.3, p=0.002), while, diastolic blood pressure was the only parameter related to LVESD (β=0.2, 95% CI: 0.04 -0.3, p=0.01) by stepwise multiple regression analysis in the diabetic patients. This result is in agreement with the findings of Fox et al (25), who stated that body mass index, surface area and blood pressure influence left ventricular mass and geometry. Duration of diabetes was significantly higher in our patients with LVH.…”

Lifestyle Changes for Abdominal Obesity Prevention and Encouraging Fruit Consumption May Be Beneficial in Preventing Left Ventricular Hypertrophy in Sub-Saharan African and Maghreb

“…Nevertheless, the existence of a functional estrogen receptor in the ventricular myocardium suggests that estrogens could be double-edged knives which, beyond their protective effect, could affect the cellular physiology of cardiac tissues both genomically and nongenomically [15], leading to greater LVM. Obesity is a risk factor for LVH [16] [17]. Moreover, since obesity and overweight are more common in black than in white [18], it has been postulated that body composition is the basis for the difference in prevalence of LVH between the two ethnic groups; but Mark et al have demonstrated that this ethnic disparity on LVM persisted after adjustment for body composition [19].…”