Geographic Location Affects Health Risks in Older Adults

It’s widely recognized that our health is determined by more than our genetics. Socioeconomic factors, physical activity, nutrition, substance use, and even job stress are among the many other factors that play a role. Now, Yale researchers, led by Robert D. Becher, MD, associate professor of surgery (general, trauma, and surgical critical care) at Yale School of Medicine (YSM), recently published two studies that identify populations of older Americans that could be at greater risk for earlier death or disability based on where they live.

The researchers created new composite indices to identify populations of Americans 65 years of age and older whose overall health could be affected by specific state- and county-level conditions. These indices—the geriatric index of state-level health policy contextual disadvantage (called the “GERi-State” index) and the geriatric index of county-level multi-dimensional contextual disadvantage (the “GERi-County” index)—consider measurements such as tobacco taxes and the number of older adults living below the poverty line at the state level, and median household income and physician density at the county level, to assess health risks for older Americans.

The researchers found that older Americans in the lowest 20% of both the state and county-level indices were at significantly higher risk for mortality. Older Americans in the lowest 20% of the county-level index were more susceptible to several types of age-related health conditions, including frailty, probable dementia, and disability, meaning the inability to perform tasks associated with daily living, such as getting out of bed and getting dressed. Their findings were published in Health and Place and the Journal of the American Geriatrics Society.

Becher, a surgeon by training, explains that his interest in geriatric health outcomes based on geography came about because of the differences he saw in post-surgical outcomes among his older patients. He notes that while one in every seven older Americans will need major surgery at some point in the years ahead, in his own practice he observed that some patients experienced significantly better recovery than others. That led him to ask deeper questions about what kinds of factors affect older Americans’ overall health outcomes.

“One of the most consistent findings in the medical literature is that place matters,” he explains. “The social, economic, environmental, and policy contexts at different geographic levels create complex structural conditions in daily life that are fundamental determinants of health outcomes, rather than just mediators.”

Becher’s goal is to understand why different populations of older adults have different outcomes after major surgery, which could ultimately lead to better health outcomes, systems, practices, and policies that improve care for all older people in the United States.

Creating single indices that measured state- and county-level factors that could contribute to health differences, Becher reasoned, would help inform health policy at the state and county levels aimed toward improving the health of older adults.

For the first study, published in the journal Health and Place, Becher and his research team, used, in part, the World Health Organization’s socio-ecological framework to help determine which factors to use in their composite indices. The framework is a theoretical model that describes the many measurable factors that shape health and health outcomes across societies.

The research team included co-senior author Thomas M. Gill, MD, Humana Foundation Professor of Medicine (Geriatrics) at YSM and professor of epidemiology (chronic diseases) at Yale School of Public Health (YSPH); Emma X. Zang, PhD, assistant professor of sociology in the Faculty of Arts and Sciences, of biostatistics at YSPH, and of global affairs; Kendra Davis-Plourde, PhD, assistant professor of biostatistics at YSPH; and Yi Wang, PhD, a postdoctoral associate in the Department of Internal Medicine at YSM.

For their indices, the researchers focused on factors that could potentially be modified at the state and county levels through legislation, for example, or improvements in health policy. They focused on variables that could be measured in all 50 U.S. states for which historical data existed for the period from 2006 to 2019. For example, state-level variables included preventable hospital stays, which are highly correlated with health care accessibility and quality; county-level variables include physician density, which predicts a local population’s ability to access preventive care as well as care for chronic conditions. States and counties were considered socially disadvantaged if they scored in the lowest 20% of the GERi-State and/or the GERi-County indices.

Using these criteria, the researchers classified 10 of 50 U.S. states and 627 of 3,132 counties as “disadvantaged.” The disadvantaged states were generally concentrated in the American South in both timeframes studied. Disadvantaged counties were more widely spread out, mostly located in the American South, as well as the southwest and western portions of the United States.

From there, the researchers looked at death rates in the 65-and-older population of each state and county being studied, focusing on community-living older adults—those who were able to participate in the life of their community, as opposed to being treated in a nursing home. The researchers examined whether the disadvantaged states and counties showed statistically significant higher rates of death in this older population.

For their second study, published in the Journal of the American Geriatrics Society, the same team of researchers, along with YSM biostatistician Brent Vander Wyk, PhD, examined rates of frailty, probable dementia, and disability, in disadvantaged vs. non-disadvantaged counties.

The researchers found that mortality rates were consistently higher in both disadvantaged counties and disadvantaged states for two time periods, 2010-2015 and 2014-2019. For these time periods (used to test the robustness of the indices over different time periods), disadvantaged states showed an 11% and a 14% increased risk of premature mortality, respectively. Disadvantaged counties showed a 10% increased risk of premature mortality in both time periods.

In the second study, the researchers found that among 7,499 study participants in the 65-and-older age range, the five-year incidence rates for all health conditions measured—frailty, dementia, and disability—were significantly higher in the disadvantaged versus non-disadvantaged counties.

Becher hopes that these studies will help highlight the importance of geography when considering the health and well-being of older Americans.

“Our research shows that these geographic factors appear to be vitally important in assessing health risks in this population,” Becher says. “These two studies are just the start of trying to understand the crossroads of older Americans, disadvantage, and health, including major surgery.”

The research reported in this news article was supported by Yale Claude D. Pepper Older Americans Independence Center (award P30AG021342), the National Institute on Aging (award U01AG032947), the National Institute on Minority Health and Health Disparities (award R01MD017298), and Yale University. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.