Findings from a new Northwestern Medicine study rebut the idea that Black individuals’ higher risk of cardiovascular disease is because of biological differences.
Black adults are at significantly higher risk [1.6-2.4 times] for cardiovascular disease than white adults. The new study found these large differences can be explained by differences in social determinants of health [like education or neighborhood-level poverty], clinical factors [like blood pressure] and lifestyle behaviors [like dietary quality].
“The key take-home message is that racial differences in cardiovascular disease are not due to race itself, which is a social concept that is not related to biology,” said corresponding author Dr. Nilay Shah, assistant professor of cardiology and epidemiology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician. “Rather, these differences in cardiovascular disease can be explained by differences in social and clinical factors. Clinicians should be evaluating the social determinants that may be influencing the health of their patients.
“The data from this study starts to identify what contributes to the higher burden of heart disease experienced by Black adults, and how much each factor matters.”
Reduce disparities by improving preventive care
Black women had a 2.4-times higher risk for cardiovascular disease compared with white women. The study found that clinical factors, neighborhood-level factors and socioeconomic factors explained the largest components of the higher risk experienced by Black women.
Black men had a 1.6-times higher risk for cardiovascular disease compared with white men. The study found that clinical factors, socioeconomic factors and lifestyle behaviors explained the largest components of the higher risk experienced by Black men.
“The findings of significantly higher risk in non-Hispanic Black adults compared with non-Hispanic white adults is not surprising — this is well-known,” said senior author Dr. Sadiya Khan, assistant professor of cardiology and epidemiology at Feinberg and a Northwestern Medicine physician. “But it was surprising that the risk for cardiovascular disease was the same once social and clinical factors were considered over time. This finding is really important to rebut that there is an unexplained or genetic reason that Black individuals have higher risk.”
The study’s findings are important because they show that disparities in heart disease experienced by Black adults could be reduced by improving preventive care of heart disease risk factors and addressing social determinants, Shah said. The data provide a guide to identify strategies that may be particularly effective at reducing the persistent differences and disparities in heart disease that exist in the U.S.
“It is important to note that clinical risk factors, lifestyle and depression are not independent of socioeconomic status and neighborhood segregation,” Khan said. “Future research needs to go upstream to target social determinants of cardiovascular health. Our study lays groundwork to help inform community-engaged interventions that ensure equal opportunities for all people to have access to high-quality foods, environments and health care."
The study evaluated data from about 5,100 Black and white adults who participated in the CARDIA [Coronary Artery Risk Development in Young Adults] Study at four locations in the U.S. [Chicago; Minneapolis, Minn.; Oakland, Calif.; and Birmingham, Ala.]. The participants enrolled around 1985 and have been followed for over 30 years. The scientists evaluated the information participants provided starting from the time of their enrollment to determine the role of social and clinical factors in the differences in cardiovascular disease experienced by Black compared with white adults over the course of 30 years of follow-up.
Other Northwestern co-authors include Norrina Allen, Dr. Donald Lloyd-Jones, Mercedes Carnethon, Kiarri Kershaw, Lucia Petito and Hongyan Ning.
BHF-funded research has shown that Black Africans, African Caribbeans and South Asians in the UK are at higher risk of developing high blood pressure or type 2 diabetes compared with White Europeans. We need to understand why this is the case so we can beat heartbreak for everyone.
How can ethnic background affect disease risk?
We funded work led by Professor Sir Michael Marmot and colleagues in the late 1980s that revealed that first-generation South Asians living in the UK have a higher rate of coronary heart disease and diabetes compared to White Europeans. Since then we have funded research to understand why South Asians and people from other ethnic minority groups are affected differently by heart and circulatory diseases.
The BHF has supported two major ongoing research studies – called LOLIPOP and SABRE – which aim to reveal how ethnic background can affect the risk of common diseases and conditions, including heart disease and diabetes.
The LOLIPOP study has been following 30,000 volunteers living in West London for nearly 20 years to identify the environmental and genetic factors that contribute to heart disease, stroke and other diseases, and to develop new tools to spot people at increased risk. Among other things, the findings could help uncover why people of Indian ancestry have a higher risk of developing heart diseases.
The SABRE study started over 30 years ago, to study the health of a group of nearly 5,000 people of European, South Asian, African and African Caribbean background in the London boroughs of Brent and Southall. Participants, now in their 70s, 80s and 90s, were recently followed up by the research team led by Professor Nish Chaturvedi at University College London. They found that the risk of developing type 2 diabetes before the age of 80 was roughly double for people with a South Asian and African Caribbean background, compared with White Europeans.
Why the pandemic has made this more important than ever
Existing health inequalities have been further exposed by the Covid-19 pandemic. People from ethnic minorities in the UK have been hit disproportionally hard by the Covid-19 pandemic. Given the links between ethnicity and heart and circulatory diseases, it is even more important that we fight to understand why.
It is vital that people of all backgrounds have opportunities to take part in research and have access to the best available treatments and care.
Recognising avoidable and unfair health inequalities linked to ethnic background is the first step to addressing the issues in society that lead to them – so it’s important that our research in this area continues.