Identifying the Causes of a Persistent Health Disparity: High Blood Pressure Among African-Americans

Jan 29, 2015, 7:31 AM, Posted by

Jacquelyn Taylor, PhD, PNP-BC, RN, FAAN, is an associate professor of nursing at Yale University and an alumna of the Robert Wood Johnson Foundation (RWJF) Nurse Faculty Scholars program (2008-2012). She recently received a $3.4 million grant from the National Institute of Nursing Research, a department of the National Institutes of Health, to conduct a large-scale study on the influence of genetic and psychological factors on high blood pressure in African-American women and children.

Human Capital Blog: Congratulations on your new grant from the National Institutes of Health to study blood pressure in African-Americans. What will be your focus?

Jacquelyn Taylor: African-Americans have the highest incidence of hypertension of any racial or ethnic group in our country. Studies show that some medications don’t work very well in reducing blood pressure in this population, and we are convinced that some other underlying mechanisms are at play. My co-principal investigator, Cindy Crusto, PhD, an associate professor in the department of psychology at Yale School of Medicine, and our research team and I will be studying two of those—genetic markers and psychological factors, such as perceived feelings of racism, mental health, and parenting behaviors—in our study. We want to know what effects these variables have on increases in blood pressure among African-American women and children over time.

HCB: Does this study build on your earlier work?

Taylor: In a previous study in Detroit, I looked at gene-environment interactions for high blood pressure in three generations of African-American women and identified hypertension risk alleles in grandmothers and in their daughters and granddaughters. Then I replicated the study in West Africa, where people live the same way as they did in the 1400s—in clay huts, with no running water, no sanitation, and no fast food as in the developed areas such as Detroit. The West African Dogon sample were mostly underweight, participated in large amount of physical activity, and had a limited but healthy diet. But they still had the same genetic markers for hypertension that I had identified in the sample in Detroit.

Then, as an RWJF Nurse Faculty Scholar, I studied the genetic and environmental risks for high blood pressure among African-American women and offspring using the HyperGen dataset, which is part of the Family Blood Pressure Program, a long-standing study of African-American participants who were recruited mainly from Mississippi and North Carolina. That study further enabled me to identify risk alleles for hypertension in children even before they developed the disease. Together, these studies led me to explore the gene-environment interactions I’m now examining at Yale.

HCB: How will your new study work?

Taylor: We will be recruiting 250 African-American children in underserved areas in Connecticut, as well as their mothers, for a total sample of 500 people. We will collect a baseline of genetic information from the mothers and their children through saliva samples, and we will assess psychological factors every six months over two years. In addition to candidate genes for hypertension, we are also taking an epigenome-wide approach to help explain risk for hypertension in this population. During each assessment, we will also collect clinical data, such as blood pressure, height, weight, and body mass index.

HCB: Why are you focusing on this population and this condition?

Taylor: Hypertension among African-Americans is a huge problem. More than 40 percent of African-Americans are diagnosed with hypertension, which can lead to other morbidities such as renal disease, stroke and ultimately death. Other studies have explored the independent effects of genetic factors and psychological stress factors that correlate with hypertension on blood pressure, but our study is the first to look at both the independent and interactive effects genetic and psychological factors have on increases in blood pressure. Another important aspect of our study is that we’re including children as young as three who have not developed hypertension yet.

HCB: What are your goals for the study?

Taylor: By the end of this study, we expect to be able to identify hypertension-related candidate genes, epigenetic factors, and psychological factors that can help explain the high prevalence of hypertension in African-Americans.

HCB: What would be the implications of those findings?

Taylor: With these findings, we hope to study therapeutic treatments for future intervention and translational studies. In other words, we would be studying the effects of individualized, rather than general, standardized treatments for hypertension. Right now, if your blood pressure is at a certain level, the standard of care is to prescribe certain medications and recommend weight loss measures and dietary changes. But if someone has a genetic predisposition or specific type of psychological stress contributing to increases in blood pressure, then anti-hypertensive medications are may not solve the problem. We need to look at the underlying mechanisms that are driving this health disparity and hone in on these individualized factors to guide the clinical practice interventions.

HCB: What do you expect to find at the end of the study?

Taylor: At the completion of this study, we expect to identify intermediate biological pathways influenced by hypertension-related genes that can help explain the high prevalence of hypertension traits in African-Americans. The findings could also highlight therapeutic targets for future interventional and translational studies for clinical prevention and treatment of hypertension secondary to effects of psychological and genetic factors. Based on the results of this study, we will seek additional funds to replicate our findings in comparable samples.

HCB: If your hypothesis pans out, what kinds of treatment do you envision?

Taylor: To treat patients with psychological markers, I envision more referrals to psychologists instead of just treating the disease with anti-hypertensive medications. For individuals with genomic markers I imagine a greater emphasis on prevention. If you already know that your child may have a genetic predisposition for hypertension, you may want to start to initiate healthier lifestyle practices early on. Additionally, for those with both genomic and psychological factors at play, I envision psychologists and nurses working together on care plans for patients that are based on an individuals’ unique profile and needs.

HCB: How did the RWJF Nurse Faculty Scholars program prepare you for your current study?

Taylor: The Nurse Faculty Scholars grant was phenomenal. I can’t say enough great things about it. It opened the door to collaborations with leaders in the field and helped pave the way for access to datasets with larger samples and, consequently, stronger results. In addition to the research component, the program incorporated the leadership training that I need now to oversee my current grant. It’s played a tremendous role in the advancement of my research agenda and role as a leader in nursing science. 

This commentary originally appeared on the RWJF Human Capital Blog. The views and opinions expressed here are those of the authors.