Largest cardiovascular disease prevention trial to date fails to reduce risk but shows lifestyle changes
Namrata Kandura, MD, MPH, professor of medicine in the department of general medicine.
South Asians in the United States — immigrants primarily from Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka — are at higher risk of developing and dying from heart disease than East Asians and non-Hispanic whites. Identifying the underlying causes has proven difficult, leading scientists at Northwestern Medicine to launch the largest cardiovascular intervention trial of its kind in the U.S. South Asian population, published in JAMA Cardiology.
Although research has attempted to explain multiple causes of increased cardiovascular disease (CVD) risk in South Asians, including risk factors such as type 2 diabetes and low physical activity, there are relatively few studies evaluating the success of attempts to improve the heart health of South Asians, one of the fastest growing ethnic groups in the United States.
The study, conducted by scientists at Northwestern University, is the largest lifestyle intervention trial in South Asian people in the United States and highlights the need to build larger studies to better represent a diverse and significantly underrepresented group.
To the scientists’ surprise, the 16-week targeted, culturally tailored lifestyle program failed to significantly reduce cardiovascular risk factors such as blood pressure, cholesterol and blood sugar levels compared to the control group 12 months after the start of the study. However, self-reports showed that study participants ate healthier, exercised more and said they felt more confident in their food and exercise choices, indicating changes in the right direction.
“This trial marks a major step forward in understanding how we can effectively support people in South Asia in managing their cardiovascular health,” said Namrata Kandula, MD, MPH, lead researcher on the study and professor of medicine in the Department of General Internal Medicine. “While the results show that our intervention alone was not enough to significantly alter clinical risk factors, the positive changes in health behaviors are promising and pave the way for more refined approaches.”
Kandura, who is also an internist at Northwestern Medicine, studies the impact of immigration on health disparities and is affiliated with a number of institutions across the university, including the Diabetes and Metabolism Center, the Center for Community Health at the Institute of Public Health Medicine and the Center for Global Cardiovascular Health at the Robert J. Havey, M.D. Global Health Institute. Kandura said he hopes the paper can serve as a model for others looking to engage diverse populations in their clinical research.
The study was tailored to the unique cultural and linguistic needs of South Asian communities: Scientists worked with community partners, including community organizations, schools, public health authorities and health coaches fluent in English, Gujarati, Hindi and Urdu, to conduct group sessions in friendly, accessible settings.
Between March 2018 and January 2022, 549 participants enrolled in the study and were randomly assigned to either a control group that received heart disease prevention information by mail every month, or a lifestyle intervention group that attended customized group classes every week for 16 weeks.
Kandura said the trial did not result in any significant changes in clinical heart disease risk, which can be explained by the timing of the coronavirus pandemic, the limited duration of the trial, and the fact that many of the health issues facing South Asians are related to environmental rather than personal factors.
“This experiment was a way for people in the South Asian community to connect, build friendships and gain support for health behavior change. It shows that improving heart health goes beyond the individual level and people need to be part of something bigger to stay motivated and supported,” Kandula said.
This research was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health (R01HL132978, R01HL132978-05S1, K24HL155897) and the National Center for Advancing Translational Sciences (UL1TR001422).
