Hypertension is strongly associated with obesity. The current childhood obesity epidemic predicts rising rates of hypertension, diabetes, and cardiovascular diseases (CVD) with earlier onset and poorer outcomes especially among minority youth. The metabolic syndrome, a clinical construct that designates multiple CV risk factors within an individual, augments greatly the risk for CVD. The association of obesity with high BP and multiple CV risk factors is strong but not universal. Not all obese adults have the metabolic syndrome, nor do all obese adults develop hypertension, diabetes or early vascular disease. Our data on a cohort of African Americans, examined from adolescence into middle age, demonstrate the presence of the metabolic syndrome at a young age, with subsequent convergence of high BP with deterioration of glucose metabolism. Despite the high prevalence of obesity in this cohort, a substantial portion of obese participants have normal BP, glucose tolerance, and plasma lipids. Preliminary data on proteins secreted by adipose tissue in the obese with high BP (OHBP) and obese with normal BP (ONBP) indicate a pro-inflammatory profile in OHBP (lower adiponectin, higher interleukin 6, higher plasminogen activator inhibitor-1) compared to the reverse pattern in ONBP. Urinary albumin excretion (UAE), a marker of vascular injury is significantly higher in OHBP and correlates with interleukin-6 and adiponectin. In contrast to evidence of a pro-inflammatory adipokine profile and markers of vascular injury in OHBP, the ONBP sample had a favorable adipokine profile and absence of metabolic risk factors despite substantial obesity. DNA analyses detected genetic variants in candidate adipokine genes, indicating a genetic contribution to the favorable and unfavorable adipokine profile. Our overall hypothesis is: Evidence of vascular injury is detectable at a young age in obesity-high BP and is associated with a pro-inflammatory adipokine profile which, in turn, is associated with the presence of genetic variants in adipokine regulatory genes. A cross-sectional study on 300 African American adolescents is designed with the following aims: Determine;1) if OHBP is a high risk clinical phenotype for multiple CV risk factors;2) if OHBP is associated with a pro-inflammatory adipokine profile;and 3) if the OHBP phenotype has evidence of CV injury, ascertained by left ventricular mass index, peripheral vascular resistance, and UAE. The contribution of genetic variants in adipokine regulatory genes will be examined. Efficient methods are needed for detection and intervention to prevent premature CVD among the substantial numbers of children who already have multiple CV risk factors and possible target organ damage. The results to this study will contribute to improved capacity for identification of high risk minority youth as well as insights for development of novel therapies to abort and reverse early stages of CV vascular injury.
Hypertension in adults results in the highest levels of morbidity and morbidity worldwide. Elevated blood pressure (BP) is detectable in the young;and the prevalence of high risk blood pressure among adolescents appears to be increasing in concert with the childhood obesity epidemic. National data indicate that approximately 17%, or >12.5 million children and adolescents in the US, are obese at this time and these numbers are increasing. Over 30% of obese adolescents, or nearly four million youth, already have high blood pressure and components of the metabolic syndrome, a condition in which vascular injury is underway. Moreover, this condition is occurring at disproportionately higher rates among minority youth. Considerable public health benefit could result from data that contribute to the development of more effective measures to identify and manage the condition of multiple risk factors and to prevent premature cardiovascular disease.
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