Analysis Details Stroke Risk from Multiple Social Determinants of Health

July 16, 2020

An analysis of the REGARDS study is shedding new light on the impact multiple social determinants of health can have on a patient's stroke risk.

In the wake of country-wide protests promoting and seeking equality, the detrimental impact of social determinants of health have also taken a step forward into the spotlight.

In a recent study, patients younger than 75 years of age who reported experiencing a single social determinant of health had a 26% higher risk of experiencing a stroke, while patients reporting 3 or more saw their risk of stroke increase by 51%.

"Our study shows that the risk of stroke is amplified among individuals with multiple social determinants of health factors, especially for those who are younger than 75 years old,” said lead investigator Evgeniya Reshetnyak, PhD, a senior research data analyst at Weill Cornell Medicine, in a statement. “There is a cumulative effect of multiple social determinants of health. In fact, every additional disadvantage further increases stroke risk.”

While past research has tied the presence of social determinants of health to worsening cardiovascular health, little data exists related to the cumulative effect of social determinants of health. Led by clinicians from Weill Cornell Medical College, Columbia University College of Physicians and Surgeons, and the University of Alabama, the purpose of the analysis was to assess the specific impact of the potential cumulative effect of having multiple social disadvantages in life.

Using information from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, investigators obtained information related to a nationally representative population of 27,813 patients aged 45 years and older for inclusion in their analysis. The mean age of this cohort was 64.7 (SD, 9.4) years at baseline, 55.4% were women, 40.4% were black, and the median follow-up time was 9.5 (IQR, 6.0-11.5) years.

The primary exposure for the analysis was presence of 10 specific social determinants of health. These included Black race, social isolation, low education, low annual household income, living in a rural area, living in a zip code with high poverty, living in a Health Professional Shortage Area, lack of health insurance, and living in a state with poor public infrastructure. Social isolation was defined as not having another person to care for you if became seriously ill or not seeing friends or family at least once a month.

The primary end point of the current analysis was expert adjudicated incident stroke. For the purpose of the study, stroke events were defined as focal neurological deficit consistent with ischemia lasting for more than 24 hours and confirmed with medical records, clinical strokes, and expert adjudicated stroke deaths.

Information obtained from REGARDS and used as covariates in the current analysis included history of heart disease, hypertension, dyslipidemia, diabetes mellitus, atrial fibrillation, and left ventricular hypertrophy. Health behavior information also included as covariates included smoking status, alcohol use, physical activity, BMI, hsCRP, urinary albumin-to-creatinine ratio, and eGFR.

During the follow-up period, a total of 1470 incident stroke events occurred. Analysis revealed 7 of the 10 social determinants of health examined in the analysis were associated with stroke (P <.10). These included race, education, income, zip code poverty, lack of health insurance, social isolation, and residence on 1 of the 10 lowest ranked states for public health infrastructure. Investigators noted a significant interaction with age resulted in stratification of patients at 75 years.

In adjusted models examining patients less than 75 years of age, risk of stroke increased as the number of social determinants of health present increased. Specifically, 1 social determinant of health increased risk of stroke by 26%, 2 increased risk by 38%, and presence of 3 or more social determinants of health increased risk by 51%.

In models examining patients 75 years of age and older, none of the observed effects reached statistical significance.

"Health care professionals should pay special attention to those patients with multiple social determinants of health,” Reshetnyak added. “Physicians should emphasize the importance of lifestyle changes, more aggressively control risk factors, and recommend available outreach and educational programs that could help reduce stroke risk."

This study, “Impact of Multiple Social Determinants of Health on Incident Stroke,” was published in Stroke.