Article In Brief
An analysis suggests that select social determinants of health like income, race, and education were linked with an increased risk of stroke, and that risk increased with the number of factors.
People under the age of 75 with three or more social determinants of health are nearly 2.5 times more likely to have a stroke than those who don’t have any of the factors, according to a new analysis of data collected for a large ongoing stroke study.
The analysis found that factors such as race, education, income, health insurance status, and social isolation were associated with an increased risk of stroke and that the risk went up the more social determinants of health a person had. The association was not found for study participants age 75 or older.
The findings, which come from data collected for the highly-published REasons for Geographic And Racial Differences in Stroke (REGARDS) study, suggest that controlling and treating established stroke risk factors such as diabetes and hypertension may be especially important in patients whose life circumstances might serve to magnify stroke risk.
“Physicians should pay particular attention to those patients with multiple determinants of health,” said study first coauthor Evgeniya Reshetnyak, PhD, a senior research data analyst at Weill Cornell Medicine. “Physicians should emphasize the importance of lifestyle changes and regular checkups, discuss stroke risks with patients, and more aggressively control the stroke risk factors.”
Educational and community outreach programs geared to stroke prevention may be especially important for those patients, she said.
“While social determinants of health are hard to change, we can mitigate the effects,” said Dr. Reshetnyak, who was part of a team of researchers from Weill Cornell Medicine and University of Alabama at Birmingham that published the findings in the July 16 online edition of Stroke.
The REGARDS Study
Dr. Reshetnyak said that while the concept of social determinants of health is not new to cardiovascular research, this latest study went a step further by looking at the cumulative impact such factors can have on individual risk of stroke.
The analysis included 27,813 participants from the REGARDS study, a national, representative cohort of Black and white adults aged 45 or older. The study, which began in 2003, was designed to examine factors leading to higher stroke mortality rates in the Southeastern US and among Blacks. While participants are from around the country, the study contains an over-sampling from Southern states that make up the so-called “stroke buckle” and “stroke belt.” By the time of this latest analysis, there had been 1,430 strokes among the participants and an average follow-up of 9.5 years from baseline.
Using the federal government’s Healthy People 2020 framework as a guide, the researchers considered 10 social determinants of health and then focused in on seven that were associated with stroke risk: race, education, income, zip code poverty, health insurance, social isolation, and residence in one of the 10 lowest ranked states for public health infrastructure.
After dividing the REGARDS cohort into two groups—participants under 75 and those 75 or older—the researchers found that among the younger group, the risk of stroke grew as an individual’s number of social determinants of health increased. When compared with stroke risk for persons with none of the factors, the risk of stroke was 44 percent higher for persons with one social determinant of health, 82 percent higher for those with two determinants, and 2.38 times higher when there were three or more.
The trend of increasing risk held even after the researchers completed statistical adjustments to account for individual characteristics of the participants, including the presence of well-known stroke risk factors. Under that analysis, stroke risk increased 26 percent with one social determinant of health; 38 percent with two; and 51 percent with three.
The association between social determinants of health and stroke did not reach statistical significance in the 75-plus group, perhaps because of selective survival, the report noted.
Among both age cohorts, those with a greater number of social determinants of health were more likely to be Black women, have low annual income (under $35,000), live in an impoverished neighborhood, and reside in a state with poor public health infrastructure. Also, those with a greater number of social determinants of health were more likely to have a history of hypertension or diabetes and take hypertension medication and insulin.
The paper said that eradicating social determinants of health “may be beyond the scope of individual physicians or health systems,” noting that “durable policy solutions are needed to eliminate the deleterious influences of SDOH [social determinants of health] on health outcomes.”
Even so, “health care providers should consider heightening their vigilance to prevent the development of risk factors and achieve improved physiological risk factor control in persons with multiple SDOH.”
The study’s limitations include the fact that the REGARDS cohort only includes white and Black individuals, so it is not known whether the findings apply to Asian, Hispanic or Native Americans. The REGARDS study did not collect data on other societal factors that might influence health, such as perceived discrimination, racism, police brutality, inequities in the criminal justice system, and exposure to environmental hazards.
A More Comprehensive View
Bernadette Boden-Albala, DrPH, director and founding dean of the program in public health at University of California Irvine, said that while stroke research has paid attention to traditional demographic and socioeconomic factors such as race, education, and income, the new study “provides a much more comprehensive view” because it focuses on a wide range of social determinants of health and how they can cumulatively increase stroke risk.
“Stroke is a disease of disparities,” said Dr. Boden-Albala, whose research focuses on this area. “This paper speaks to the fact that there are multiple biological and social mechanisms that contribute to stroke risk that we haven’t articulated well enough.”
But she said the next challenge is “how do we move from describing the determinant to understanding the mechanism by which it works?…What is the underlying mechanism and how do we intervene?”
Dr. Boden-Albala is particularly interested in how social isolation may influence stroke risk. Isolation was defined in the new stroke study as not seeing friends or family members at least once a month. Her research centers around the role of family and friend networks in reducing isolation and providing support to enhance primary and secondary stroke prevention.
Dr. Boden-Albala said that it was still unclear whether social determinants of health onto themselves increase stroke risk through inflammatory mechanisms, for example, or whether they serve to heighten the effect of traditional risk factors. For instance, a person with less education may not understand their treatment regimen for hypertension and that in turn could lead to poor blood pressure control.
“Physicians should emphasize the importance of lifestyle changes and regular checkups, discuss stroke risks with patients, and more aggressively control the stroke risk factors.”
—DR. EVGENIYA RESHETNYAK
While there is no one checklist for doctors to measure social determinants of health, non-medical details of a patient’s life often emerge during a clinical visit, Dr. Boden-Albala said. If a person has the effects of difficult life circumstances piled on top of standard stroke risks, “We have to be more vigilant about the way we reduce that risk and include social determinants in those strategies.”
With COVID, Findings Are Timely
The new findings on social determinants of health are timely given all that is going on, several stroke experts commented. The COVID-19 pandemic, which has affected Blacks and Latinos in the US disproportionately, has heightened public awareness that there are wide health disparities in this country. Protests against police brutality and racism following the killing of George Floyd by Minneapolis police officers have drawn attention to multiple injustices that Black Americans face, from under-funded schools to racial profiling to less ready access to healthcare.
“Now that the nation seems sensitized to the issues around inequities and disparities, I think this study provides even more evidence to support the importance of these social determinants of health, which in turn are influenced by societal racism,” said Olajide Williams, MD, FAAN, professor of neurology at Columbia University. “Where people live, work, learn, and play truly does affect their health, and are what we call social determinants of health.”
Dr. Williams said doctors “educate patients all the time about many things such as medication schedule adherence,” but he said this doesn’t do much good if the patient has trouble reading instructions or an educational pamphlet, or can’t afford the medication in the first place.
Dr. Williams has published research showing that targeted interventions can make a difference. A study of stroke education involving Black and Hispanic churchgoers in Harlem found that people with low levels of education may be more likely to retain information pertinent to stroke preparedness if they watched a culturally tailored 12-minute film on the subject compared to reading educational pamphlets.
Dr. Williams said he would like to see leading professional medical associations issue evidence-based stroke disparity guidelines specifically focused on best practices among populations with high counts of social determinants of health.
“We often refer these patients to social workers or care coordinators where they exist. But I do think there needs to be a much more coordinated approach regarding how we treat these vulnerable patients,” Dr. Williams said.
He said he would welcome “a guideline document that reviews the literature for best practices and comes up with practice-based recommendations and important knowledge gaps.”
Joseph P. Broderick, MD, FAAN, professor of neurology and rehabilitation medicine and director of the University of Cincinnati Gardner Neuroscience Institute, said that realistically “doctors by themselves don’t have the ability to resolve societal issues,” something that he said requires politicians, policymakers and, most importantly taxpayer and community support.
He noted that Hamilton County, OH, where his center is located, has passed a tax levy for many years that helps fund care for indigent patients, something he said makes him proud of the community where he lives. He said universal healthcare would help solve many problems patients face, such as lack of access to primary care physicians and needed medications.
Dr. Broderick said he thinks of social determinants of health as markers for disease risk and said the challenge for doctors when devising treatment plans is “how do we minimize that disadvantage as much as possible?”
He said ideally health interventions targeting patients with social determinants of health would occur at the primary care level since, by the time neurologists see stroke patients, the damage has already occurred.