All ETDs from UAB

Advisory Committee Chair

Jose R Fernandez

Advisory Committee Members

Timothy M Beasley

Maria Deluca

Douglas Heimburger

Gary R Hunter

Document Type

Dissertation

Date of Award

2010

Degree Name by School

Doctor of Philosophy (PhD) School of Health Professions

Abstract

Elevated blood pressure and nonesterified fatty acids (NEFA) in children can lead to increased chronic disease risk during adulthood. The atrial natriuretic peptide precursor A (NPPA) and natiuretic peptide receptor A (NPR1) genes encode for atrial natriuretic peptide (ANP) and its cell receptor, respectively, and may influence levels of blood pressure and NEFA. Additionally, it is unclear how body composition, physical activity, physical fitness, and racial genetic ancestry influence pediatric NEFA and blood pressure. In order to understand the associations among these factors, five investigations were performed. For experimental aim 1, the association between blood pressure and body composition measures was evaluated to determine which measure of body fat is most associated with blood pressure. The results indicate that increased waist circumference, a measure of central adiposity, is associated with pediatric hypertension. For experimental aim 2, physical fitness and physical activity were measured and their association with pediatric blood pressure evaluated. These findings indicate that low physical fitness, rather than activity, is associated with increased pediatric hypertension risk. Results from experimental aim 3 suggest that physical fitness varies by percent body fat, and that percent fat is a more reliable indicator of physical fitness level than body mass index. For experimental aim 4, results suggest that the relationship between fasting NEFA and hypertension status is dependent on racial genetic ancestry. For experimental aim 5, results from the previous aims were used to develop statistical models to test the association of the NPPA (rs5063, rs5065, rs198358) and NPR1 (rs10082235) genes with fasting NEFA and blood pressure. Increased prevalence of hypertension was noted among carriers of the GA allele of rs5063. Carriers of the rs10082235 TT allele had higher fasting NEFA and a trend for increased hypertension. Additionally, higher rates of African racial ancestry were associated with hypertension risk, while greater Amerindian was associated with higher fasting NEFA. Overall, these results indicate that central adiposity may affect blood pressure, but that physical fitness is the main predictor of hypertension and elevated NEFA risk. They also suggest that a similar genetic/biological mechanism may control both blood pressure and NEFA levels.

Share

COinS