Left Ventricular Mass In African Americans Research Articles

SNP-SNP interactions dominate the genetic architecture of candidate genes associated with left ventricular mass in african-americans of the GENOA study

BackgroundLeft ventricular mass (LVM) is a strong, independent predictor of heart disease incidence and mortality. LVM is a complex, quantitative trait with genetic and environmental risk factors. This research characterizes the genetic architecture of LVM in an African-American population by examining the main and interactive effects of individual candidate gene single nucleotide polymorphisms (SNPs) and conventional risk factors for increased LVM.MethodsWe used least-squares linear regression to investigate 1,878 SNPs from 234 candidate genes for SNP main effects, SNP-risk factor interactions, or SNP-SNP interactions associated with LVM in 1,328 African-Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. We reduced the probability of false positive results by implementing three analytic criteria: 1) the false discovery rate, 2) cross-validation, and 3) testing for internal replication of results.ResultsWe identified 409 SNP-SNP interactions passing all three criteria, while no SNP main effects or SNP-risk factor interactions passed all three. A multivariable model including four SNP-SNP interactions explained 11.3% of the variation in LVM in the full GENOA sample and 5.6% of LVM variation in independent test sets.ConclusionsThe results of this research underscore that context dependent effects, specifically SNP-SNP interactions, may dominate genetic contributions to variation in complex traits such as LVM.

Relation of coronary artery calcium to left ventricular mass in African-Americans

Both coronary artery calcium (CAC) deposits and increased left ventricular (LV) mass are important risk factors for coronary heart disease, but the relation between these 2 factors has rarely been studied. We examined the correlation of CAC and LV mass in 159 young to middle-aged African-Americans, and found that the average LV mass indexes were bigger in the CAC-positive groups than in CAC-negative groups in both genders (p = 0.0004 in men; p = 0.08 in women).

Insulin Resistance Syndrome and Echocardiographic Left Ventricular Mass in African-Americans

P70 The insulin resistance syndrome (IRS) has been associated with cardiovascular disease (CVD), but few studies have examined its relationship with subclinical measures such as echocardiographic left ventricular (LV) mass. This relationship is likely to be of particular importance in African-Americans where both IRS and elevated LV mass are common. Complete information was available for 1633 African-American women and men aged 49-73 who were enrolled in the Atherosclerosis Risk in Communities (ARIC) Study when M-mode echocardiography was performed at one of the four ARIC sites in Jackson, Mississippi (1993-1996). LV mass was calculated according to American Society of Echocardiography methods using the cube formula and was indexed by height. Participants were categorized by the number (0, 1, 2, or 3) of IRS characteristics (hypertension, dyslipidemia (low HDL cholesterol or high triglyceride), and glucose intolerance (diabetes or fasting glucose values ≥110 mg/dl)). Age-adjusted mean LV mass/height (g/m) increased progressively with increasing number of IRS disorders in both women and men (128.9, 148.6, 161.0, 171.6 and 135.9, 157.4, 170.6, 171.6 respectively, p<0.001, tests for trend). Associations were slightly stronger in women than in men and were similar when participants were stratified by age, BMI and waist circumference. These associations were not altered by adjustment for smoking and alcohol intake, and were only slightly attenuated with adjustment for BMI and waist circumference. Analyses focusing on the components of LV mass revealed that posterior wall and interventricular septal thickness, but not LV chamber size, were significantly associated with the number of IRS disorders. In this large population-based study of middle-aged African-American women and men the degree of IRS clustering was strongly and independently related to LV mass and these associations are consistent with a possible influence of insulin resistance on myocardial thickening rather than chamber size.