Social and Biological Predictors of Blood Pressure in Hypertensives.

Abstract

Hypertension affects 1 in 4 adults in the United States and is a major contributor to cardiovascular morbidity and mortality. Blood pressure (BP) control is observed in slightly less than two-thirds of those on antihypertensive pharmacologic treatment, and racial/ethnic disparities persist with significantly lower BP control rates observed among minority populations. Hypertension is a multifactorial disease, involving both genetic and environmental pathogenic mechanisms. This dissertation used the Genetic Epidemiology Network of Arteriopathy (GENOA) study to examine (1) cross-sectional associations of individual characteristics (demographic, medical history, physiological, and lifestyle) with BP outcomes, (2) cross-sectional associations of neighborhood socioeconomic environment with BP outcomes, (3) familial aggregation of BP outcomes, and (4) cross-sectional associations of gene-drug interactions with systolic blood pressure (SBP). The first study found that BP control rates were suboptimal among treated hypertensives, and BP control rates were lower among African Americans, compared to non-Hispanic whites. Increasing age and the presence of co-morbidities were associated with decreased odds of BP control. Individual education was significantly associated with BP control in African Americans, but not non-Hispanic whites, net other individual level factors. The second study found that neighborhood socioeconomic environment was associated with increased odds of combination antihypertensive pharmacological therapy, but not BP control, among African Americans. The third study found evidence of moderate familial aggregation of quantitative BP measures and BP control in both African Americans and non-Hispanic whites. Among African subjects, sib-sib correlations of quantitative BP values and familial aggregation of BP control were detected among sibpairs in which both siblings resided in poor neighborhoods. The fourth study found that single nucleotide polymorphisms in the SELE and VCAM1 genes had significant main effects, as well as gene-drug interaction effects, on SBP in both African Americans and non-Hispanic whites. Findings from these studies illustrate the multifactorial nature of hypertension and the importance of understanding how multiple factors across multiple levels influence variation in BP levels. This dissertation research took important, novel steps in building connections between the physiological, lifestyle, socio-demographic, familial, genetic and antihypertensive therapy factors that influence BP control in hypertensives from the general clinical population.