by EMILY AYSHFORD, WILL DOSS, HILARY HURD ANYASO, MARLA PAUL, and MELISSA ROHMAN
Northwestern investigators uncover health disparities while advocating for health equity.
While the medical field has made major strides in the prevention and treatment of disease in recent decades, far too many people have been left behind. Black adults, for example, are 20 percent more likely to die from heart disease than non-Hispanic whites, while Hispanic adults are 50 percent more likely to die from diabetes than white adults. LGBTQ populations also face disparities, with greater risks for heart disease and mental health conditions.
This year, COVID-19 has put an additional spotlight on disparate health outcomes: Black and Hispanic COVID-19 adult patients face nearly five times the rate of hospitalization as white people, and both Black and Hispanic children with COVID-19 have much higher hospitalization rates than white children.
Scientists and physicians across Feinberg are working to not only identify disparities in health outcomes among different racial, ethnic, geographic, and socioeconomic groups — they are also working to change the many systems that allow these disparities to exist and grow.
Some of this work happens in Northwestern’s Institute for Public Health and Medicine (including in its Center for Health Equity Transformation, Center for Epidemiology and Population Health, and Center for Community Health, which has an equal presence in the Northwestern University Clinical and Translational Sciences Institute), while other research stems from cross-departmental collaborations.
“What’s really notable about Northwestern is that disparity research is not restricted to a single department or institution here,” says Mercedes Carnethon, PhD, vice chair of the Department of Preventive Medicine. “You can find people in every department at Feinberg, in every discipline — from basic scientists to population scientists — who are focused on addressing disparities and developing strategies, using different methods.”
“I think it’s a growing area of research at Northwestern,” adds Kiarri Kershaw, PhD, MPH, assistant professor of Preventive Medicine in the Division of Epidemiology. “We’re getting a critical mass of disparities investigators with expertise in many different areas, and that’s exciting.”
Finding patterns among disparities
Before disparities can be addressed, they must be specifically defined. Many Feinberg investigators are studying patterns of disease among populations — often finding results that reveal previously unknown patterns or upend racial stereotypes.
In 2018, Carnethon published a study in JAMA that revealed Black and white people have the same risk of developing diabetes when taking into account biological risk factors, such as obesity. The study obliterated the idea that there is an unexplained or genetic reason why Black adults have twice the rate of diabetes, as compared to white adults.
“It may seem like the answer is simple — don’t gain weight — but the solution is actually really complicated, because of different accesses to resources and preventive care,” Carnethon says. “We hope our research is informative to people who can really take it to the next level and think creatively about a comprehensive and complex set of strategies to reduce this disparity.”
Carnethon also published a paper that year that found that, across the board, Black people have poorer overall cardiovascular health than non-Hispanic whites. Other Feinberg investigators have found similar results. This year, Sadiya Khan, ’09 MD, ’14 MS, ’10, ’12 GME, assistant professor of Preventive Medicine in the Division of Epidemiology and of Medicine in the Division of Cardiology, found that deaths due to heart failure and hypertensive heart disease are increasing in the United States, especially among Black women and men. In a study published in The British Medical Journal, Khan looked at mortality data from 1999 to 2018 across a spectrum of heart disease types, looking at differences between sex and racial groups across age groups and geography. She found that deaths from heart disease in 2018 equaled 3.8 million potential years of life lost. Not only that, the loss was 30 percent and 60 percent greater for Black men and women compared with white men and women, respectively.
“We have to recognize and address that the root causes of these disparities arise from differences in social determinants of health, such as socioeconomic status and access to care, and structural and systemic racism in our country,” Khan says.
Such disparities don’t just affect cardiovascular health. In a study published in JAMA Neurology, Norrina Allen, PhD, ’11 GME, director of IPHAM’s Center for Epidemiology and Population Health and associate professor of Preventive Medicine in the Division of Epidemiology, found that higher cumulative blood pressure among Black patients is a major contributor to their higher risk of dementia.
Using five large population cohorts totaling nearly 20,000 individuals, Allen and her collaborators analyzed the interaction between cumulative blood pressure and changes in cognitive function. They found that high blood pressure over time was associated with significantly faster cognitive decline.
“We have known for decades that African Americans experience an excess burden of hypertension and hypertensive-related outcomes,” Allen says. “This study expands our understanding of the impact of these blood pressure disparities to demonstrate they are additionally responsible for racial disparities in cognitive decline with age. Prevention of hypertension, particularly focusing on Black communities, is critical to addressing racial disparities in a broad range of health outcomes.”
Understanding the effect of social environments
Health disparities often stem from social environments — something that Kershaw realized when she initially tried to understand differences in air pollution exposure or supermarket access by race. “The common themes were these underlying structural factors,” she says, such as racial and ethnic segregation. Kershaw has focused her career on understanding how these factors affect health disparities in areas like cardiovascular and mental health.
In a study published in JAMA Neurology, she found that Black people who experience racial segregation in their neighborhood during young adulthood are more likely to have poor cognitive performance, even as early as midlife.
She also found that systolic blood pressure readings of Black people dropped between one to five points, over 25 years, when they moved to less-segregated areas. That research was published in JAMA Internal Medicine.
Even income can have an adverse effect on health, she found. In a study published in Circulation, she showed that long-term income volatility increased the risk for both cardiovascular events and overall mortality.
Now, she is beginning a study that uses ECG monitors to measure how stressed participants are, and how they respond to stressful situations in real time. She and her collaborators will also use GPS to track participants’ locations, and will ask them questions about diet and exercise, to get a better sense of how geography and environment might affect stress levels.
Striving for systemic change
Identifying health and healthcare disparities is a major first step, but investigators are also working to close gaps — something that requires major systemic change.
In a recent discussion paper published by the National Academy of Medicine, Melissa Simon, MD, MPH, GME ’06, the George H. Gardner, MD, Professor of Clinical Gynecology, and founding director of the Center for Health Equity Transformation, argued that one way to achieve health equity is through a “patient and family engaged care” culture.
That means providing care that genuinely centers around patients and their families of all communities, which would require “a transformational culture shift in the way institutions are structured at every level, from the way they deliver patient care, to their teaching, scholarship, policies, and practices,” she says.
What’s really notable about Northwestern is that disparity research is not restricted to a single department or institution here.” Mercedes Carnethon, PhD
“It starts with the leadership, the highest levels of leaders in all aspects of an institution. There are many people already working in healthcare delivery institutions and at academic health centers that have the talent and ability to be appointed to high-level leadership positions and who are Black, Indigenous, or people of color, but aren’t given a chance for a variety of reasons, including long-standing systemic racism.”
The need for systemic change has especially come to light in 2020. COVID-19 has illuminated vast differences in health outcomes, and civil unrest and the Black Lives Matter movement have put an additional spotlight on structural racial inequities.
“It highlights the importance of addressing structural determinants of health,” Kershaw says. “We have done a better job of characterizing the problem, but we’re still far away from a solution. These issues show the need to really focus and tackle root causes.”
Considering where disparities originate is needed if Northwestern wants to be a leader in both making changes to the healthcare system and in effecting change within communities more broadly, Allen says. In the Center for Epidemiology and Population Health, she and others are working to understand how some populations of infants and children begin to accumulate risk factors for cardiovascular disease, like obesity. “We want to know how we can intervene early to help mitigate these risk factors from the start,” she says. “We’re really focused on creating a healthy life for all.”
Social Inequities in COVID-19
In June, a multidisciplinary team of Northwestern investigators received a $200,000 grant from the National Science Foundation to create a web-based, no-contact research platform to investigate the origins of social inequities in COVID-19 across neighborhoods in Chicago.
The team, which includes experts from the University’s Institute for Sexual and Gender Minority Health and Wellbeing (ISGMH), has recruited participants from different areas of Chicago to use a finger stick dried blood spot (DBS) sample kit that will allow investigators to analyze the sample for IgG antibodies against the receptor binding domain of SARS-CoV-2, the virus that causes COVID-19.
Participants, who use the kit at home and mail it in, also take a survey. Antibody test results will be combined with survey responses and neighborhood-based administrative data to investigate the individual-, household- and community-level predictors of exposure.
“The goals of this project are inherently about understanding the causes and solutions to the dramatic race and place inequities in COVID-19 across the city of Chicago and in other communities around the county,” says Brian Mustanski, PhD, director of ISGMH and professor of Medical Social Sciences and of Psychiatry and Behavioral Sciences.
To create the system, the team adapted technology used to study at-home HIV and sexually transmitted infection testing for young gay and bisexual men. The team also helped craft research questions that focus on understanding and addressing the racial and geographic disparities in COVID-19 across Chicago and the United States.
“In addition to our team’s focus on sexual and gender minority communities, ISGMH investigators draw from an intersectionality perspective and have achieved excellent recruitment of racial and ethnic minority participants in our research. We are leveraging that experience to support enrollment into the current COVID-19 study,” Mustanski says.
In addition to Mustanski, the team is made of up of Thomas McDade, PhD, the Carlos Montezuma Professor of Medical Social Sciences and of Anthropology at the Weinberg College of Arts and Sciences; Elizabeth McNally, MD, PhD, the Elizabeth J. Ward Professor of Genetic Medicine and director of the Center for Genetic Medicine; Alexis Demonbreun, PhD, assistant professor of Pharmacology; Richard D’Aquila, MD, director of the Northwestern University Clinical and Translational Sciences (NUCATS) Institute and the Howard Taylor Ricketts, MD, Professor of Medicine in the Division of Infectious Diseases and associate vice president of research; and Nanette Benbow, MA, research assistant professor of Psychiatry and Behavioral Sciences.