Understanding Geographic Patterns of Stroke

A profile of Medellena Maria Glymour, MS, ScD, Health & Society Scholar, 2006-2008

    • July 6, 2011

The problem. Residents of Southeastern states have shown a long-standing pattern of having more strokes and a higher death rate from strokes than people living in other geographic areas in the United States. But should this medical condition be attributed to where someone lives at the time of the stroke, or is it instead due to whether someone grew up in the South, early exposure to certain risk factors (e.g., exposure to tobacco) or educational opportunities?

Grantee perspective. Researcher and social scientist Medellena Maria Glymour, MS, ScD, has always been interested in social determinants of health—defined as the conditions in which people are born, grow, live, work and age.

After graduating from the University of Chicago in 1996, she earned her master's degree from the Harvard School of Public Health in 2000 and then received a Doctor of Science degree from Harvard in 2004, focused on social determinants of health. Glymour spent the next two years as a Harvard research associate and instructor, and soon realized that she wanted additional exposure to interdisciplinary approaches to help broaden her research.

In Robert Wood Johnson Foundation Health & Society Scholars program, Glymour found the opportunity she was looking for to "deepen the way that I thought about my research questions, not to fundamentally change my thinking, but to expose me to some things that are valuable." In 2006, she began her two-year interdisciplinary fellowship at Columbia University, one of the six universities participating in the Health & Society Scholars program.

"That was exceptional," Glymour said of her exposure to interdisciplinary perspectives and new disciplines at Columbia. "It helped me think more broadly about ways that social factors affect health."

Results. As a Health & Society Scholar, Glymour investigated the relationship between geographic risk factors and adult cognitive impairment and stroke. Using data from the University of Michigan Health and Retirement Study, Glymour focused on factors such as smoking, exposure to tobacco smoke and race that may contribute to elevated stroke rates among those who live—or had lived as children—in one of seven Southeastern "Stroke Belt" states (which Glymour's study defined as Alabama, Arkansas, Georgia, Mississippi, North Carolina, South Carolina and Tennessee; other sources include up to 11 states). Started in 1992 and supported by the National Institute on Aging and the Social Security Administration, the Health and Retirement Study surveys more than 22,000 Americans over the age of 50 every two years.

"We had known for a while from mortality data that people in the Southeastern states have higher mortality rates from strokes, but we were not able to explain why," said Glymour, who studied 18,070 survey respondents living in the Stroke Belt who all told had 1,452 strokes. "Maybe it was not about where you live as a grown-up but something that happened earlier in life."

Glymour published her initial findings in an article called "Is the 'Stroke Belt' Worn from Childhood?" in Stroke: Journal of the American Heart Association (38: 2415–2421, 2007). In the article, Glymour and her co-authors reported that:

"Stroke Belt residence predicts excess stroke risk because of exposures experienced in early life. Place of residence may affect stroke through access to medical care, physical risks associated with environmental conditions, social norms affecting behaviors, socioeconomic conditions created by local macroeconomic factors, or psychosocial pathways stemming from features of social organization in communities."

They concluded:

"...individuals who had resided in the Stroke Belt in childhood experience heightened stroke risk at ages 50 and older, even if they had migrated out of the Stroke Belt, implicating early-life exposures in the genesis of the Stroke Belt."

Glymour's work as a Health & Society Scholar resulted in the publication of four other articles on stroke occurrence and Stroke Belt relationships, published in Neurology (73(22): 1858–1865, 2009); Stroke (40(3): 873–879, 2009); the Journal of the American Geriatrics Society (57(3): 499–505, 2009); and the American Journal of Preventive Medicine (35(3): 245–248, 2008). Glymour noted that having the time to publish was one of opportunities she appreciated most about the Health & Society Scholars program.

Since completing her fellowship in 2008, Glymour has continued to build on her Health & Society Scholars research to advance knowledge about stroke and related conditions. Under a grant from the National Institute on Aging (2010 to 2012) called "Functional Impairments From Stroke: An Exploratory Study of Disparities," Glymour is exploring racial and geographic patterns of atrial fibrillation, an irregular and often rapid heart rate that is known to dramatically increase the risk of stroke. Glymour is also researching the link between education and cognitive functioning.

Glymour continues to be in contact with colleagues and mentors from the Health & Society Scholars program and she recognizes the program's lasting benefits. "When I interviewed for the program, Peter Bearman, then director of the Lazarsfeld Center for the Social Sciences at Columbia, told me, 'This program is just a gift. You have two years to think,'" said Glymour. "Now, I can say, 'Yes, that is a wonderful way to describe it.' The program allowed me to develop my own research agenda, to distinguish myself from primary mentors. That is a huge gift."

RWJF perspective. RWJF created the Health & Society Scholars in 2001 to build the field of population health. "There is a growing recognition that health is the result of the interaction of multiple factors including socioeconomic and physical environmental factors and health behaviors," said Senior Program Officer Pamela G. Russo, MD, MPH, leader of RWJF's Public Health Team. "The evidence shows that these types of factors play a much larger role in determining health at the population level than do the traditionally considered health care and biological determinants of health."

"The program seeks to integrate paradigms and knowledge from a variety of disciplines to develop an understanding of how these determinants affect the health of populations, and thereby to design interventions with greater power to reduce health disparities," said Russo.