June/July 2020 Issue

Social Determinants of Health — Looking Beyond the Individual
By Carrie Dennett, MPH, RDN, CD
Today’s Dietitian
Vol. 22, No. 6, P. 32

Why the Origins of Chronic Disease Are Complex and Often Hidden

A secure job with benefits. A strong and vibrant community. Safe and affordable housing. An easy-to-navigate neighborhood with parks and community spaces. Access to healthful and affordable food. Opportunities to pursue education. These are things we want for ourselves—and for others. But what dietitians may not realize is that having, or not having, these“social determinants” affects our health and that of our clients and patients. As dietitians, our focus is primarily on behavior change. But what if the root causes of disease have less to do with behaviors and personal choice than we think?

What Are Social Determinants of Health?
Social determinants of health (SDOH) are a subset of determinants of health—the personal, social, economic, and environmental factors that influence health status.1 This broader group also includes the following:

• government policies;
• individual behaviors: diet, physical activity, use of drugs such as alcohol and cigarettes, hand washing, seatbelt use, and safe sex practices;
• biological and genetic factors: age, sex, HIV status, inherited conditions, and genetic risks; and
• health services: availability, affordability and/or insurance coverage, and access to interpreters, if needed.

The World Health Organization (WHO) defines SDOH as “the conditions in which people are born, grow, live, work, and age.”2 They include the following:

• Social factors such as educational and job opportunities, living wages, access to nutritious food and safe drinking water, discrimination, crime rates and exposure to violent behavior, social support and community inclusivity, early childhood experiences and development, exposure to media and technology, quality of schools, transportation options, public safety, residential segregation, and concentrated poverty.
• Place-based, or “physical” conditions, including the natural environment (plants, weather, or climate change), the built environment (buildings and transportation), exposure to toxic substances or physical hazards, physical barriers (especially for people with disabilities), aesthetic elements (good lighting, trees, benches), and other aspects of our worksites, schools, housing, recreational settings, and neighborhoods.

SDOH are shaped by distribution of money, power, and resources at local, national, and global levels. According to the WHO, SDOH are responsible for most of the differences in health status within and between countries. A change in one of these social factors can trigger many other changes that affect health. For example, education affects health literacy, but many other factors affect ability to attain an education, most obviously income, but also racism, sexism, and other forms of stigma, bias, and discrimination.3

What Impact Do SDOH Have on Health?
While social factors may shape behaviors—for example, people with higher education and income may have more knowledge about nutrition and buy healthful food because they can easily access and afford it—this is only part of the picture.

A 2011 meta-analysis found that the number of deaths in the United States in 2000 attributable to social factors—including low education, racial segregation, and lack of social support—was comparable to the number of deaths due to disease and behaviors.4 In areas such as adult obesity, asthma, mental health, cancer, myocardial infarction, and type 2 diabetes, a 2016 study found that states that spend more on social services and public health than they do on medical expenditures substantially have improved health outcomes compared with states that spend less.5

A 2010 US study found that health increases as social position—based on both socioeconomic status and race/ethnicity—increases. Notably, while those with the lowest income and education were consistently least healthy—as might be expected—for most indicators, groups with mid-range income and education levels were less healthy than the wealthiest and most educated groups. Indicators included coronary heart disease, diabetes, life expectancy, overall health status, and activity limitation.6 Gradients based on income and education were least apparent among Latino people, for reasons that are unclear.6,7

Of course, association isn’t causation, and showing causation is challenging, in part because the impact of SDOH doesn’t lend itself to randomized controlled trials. However, the presence of a graded relationship, rather than simply differences based on a clear threshold such as the poverty line, suggests a dose-response relationship, supporting the idea of a causal role.8

Mapping SDOH Pathways
SDOH don’t operate in isolation. Together, they form a complex, multidirectional web. For example, access to education means gaining skills that make it easier to find a good job that pays well, which makes it easier to pay the rent or mortgage and bills. Having good and affordable housing frees up money to pay for food. Safe, well-connected streets make it easier to get where you need to go.

When individuals have all of these things, it’s easier to connect with neighbors and their community. If they have kids, it makes it easier to help them do well in school.

On the other hand, poor health or lack of education can limit employment opportunities, which lowers income. Low income reduces access to health care, nutritious food, and safe housing, which increases hardship. Hardship creates stress, which in turn can lead to unhealthful coping mechanisms such as substance abuse and overeating of unhealthful foods.

Some pathways are direct and immediate. For example, exposure to pollution exacerbates asthma, which may result in more sick days and decreased physical activity. Other pathways are indirect but still play out over a relatively short term.

For example, adolescents in families with lower socioeconomic status are less likely to get enough sleep, which may contribute to poor academic performance, depression, behavioral difficulties, and health problems.9 If individuals don’t have paid sick leave, they’re more likely to go to work when sick, which can have public health repercussions if they’re food handlers.8

Dietitians have watched some of these pathways play out starkly during the COVID-19 outbreak, which disproportionately has affected black Americans. This is due to a combination of reduced access to testing and delayed care—partly due to racial bias—and differences in employment status. Black workers are much less likely to have jobs that allow working from home, and people of color are overrepresented in low-wage but “essential” public-facing jobs that may not offer health insurance or paid sick leave. Structural inequalities also contribute to higher rates of the comorbidities that increase risk of respiratory complications.

Other pathways take longer to play out, with health effects taking years or decades to emerge. For example, people who live in neighborhoods with little access to fresh produce or outdoor recreation but easy access to fast food are more likely to have poor nutrition and low levels of physical activity, which can contribute to chronic disease later in life.8,10

Discussions of SDOH often include the idea of “upstream and downstream.”10 Downstream are health outcomes requiring treatment, midstream is behavior modification, and upstream are SDOH—the causes of the causes. By going upstream, we can eliminate the cause of the problem rather than just treat its effects.

While we may think of behaviors as a cause of poor health, sometimes the pathways from SDOH to health outcomes aren’t only long and indirect but also don’t even involve potentially modifiable “midstream” behaviors.8 Chronic stress may be the link.

Allostatic Load and ‘Weathering’
Chronic exposure to social and environmental stressors—known as allostatic load—can lead to physiologic changes.10,11 For example, stress can raise levels of proinflammatory molecules such as C-reactive protein, and lower income and education contribute to high blood pressure and unhealthy cholesterol levels.8,12

All of these factors can increase the risk of CVD. Early childhood—a time of major brain development—is a critical window, and socioeconomic disadvantage during this window is linked to increased disease risk and decreased immunity later in life, even when socioeconomic status and social position improves in adolescence and adulthood.8,13

Epigenetics—the study of heritable changes in gene expression that occur without changes to DNA—may explain other pathways, including changes in telomere length. Telomeres are protective “caps” on the ends of chromosomes, and telomere shortening is considered a marker of cellular aging. Educational attainment, work schedules, perceived stress, and whether someone works in a manual or nonmanual job all have been linked to changes in telomere length.8

The complex and often indirect nature of the pathways between SDOH and health outcomes, along with the length of time they take to develop, makes them nearly impossible to study using randomized controlled trials. In the case of epigenetics, the causal pathways may take more than one generation to manifest.8,10

For example, deaths from heart disease declined dramatically between 1968 and 2014, but those rates of decline have been significantly slower among black Americans in areas of the United States that had the highest concentration of slavery in 1860.14

Epidemiologic studies consistently have documented that blacks living in the United States have higher rates of physical illness such as hypertension and diabetes, and higher rates of mortality, but lower or similar rates of depression, when compared with non-Hispanic whites. This is after controlling for socioeconomic factors.

One hypothesis was that blacks were more likely to use unhealthful coping mechanisms (eg, alcohol and nicotine consumption, and overeating), but a 2011 study found that at all levels of stress, whites were more likely to use alcohol and nicotine.15

While there may be some role for genetics, the fact that hypertension rates in the United States are disproportionately higher in black men, and, to a slightly lesser extent, black women, is largely due to social factors, including interpersonal and institutional racism.16-18

Black men who have greater social and economic resources and the ability to name and challenge discrimination have some protection against hypertension, whereas black men with low socioeconomic status try to persevere in the face of adversity—known as John Henryism—and have especially high hypertension rates.16,19

Related to that, black women have significantly increased risk of the hypertensive disorder preeclampsia during pregnancy, which if left untreated can kill both mother and baby.20

Disparities in maternal health outcomes between black and white women may be due to “weathering,” early health deterioration due to social inequality. For example, white women in their 20s are more likely to give birth to a healthy baby than those in their teens, but the reverse is true for black women.20,21 Black women in their 20s are less likely to give birth to a healthy baby than those in their teens.

Weathering also may explain why black women are two to three times more likely to develop harder-to-treat hormone receptor–negative types of breast cancer, despite no evidence of predisposing genetic factors associated with African heritage.22 In addition, weathering may explain some of the increased impact of COVID-19 on black Americans.

How SDOH Affect Nutrition
Evidence is clear that income level is associated with diet quality, but what’s less clear is the exact causal pathways. Data are inconsistent on how much of a role the price of nutritious foods and the time it takes to prepare them play. A 2017 study in the American Journal of Preventive Medicine suggests social factors that often coexist with low income—job, food, and housing insecurity—along with resulting stress, poor sleep, and cognitive burden, may have the greatest impact on dietary intake.23

Conditions of uncertainty and threat can contribute to a scarcity mentality, which makes it hard to manage challenges, leading to a decline in diet quality when combined with low income. These conditions also activate hormones that regulate stress, appetite, and hunger. When children experience scarcity, they’re more likely to be impulsive and vulnerable to temptation as adults, which can result in making food choices based on palatability and immediate gratification rather than nutrition, even when healthful food is available and affordable.23

Sandra Arevalo, MPH, RDN, CDN, CLC, CDCES, FADA, a spokesperson for the Academy of Nutrition and Dietetics and outreach director for Montefiore Medical Center’s community programs in New York, gives the example of a male patient who would eat only cake, soda, rice, and beans.

“No matter how much I tried to change my patient’s diet, he would not change,” she says. “It turns out he had been incarcerated, and craved cake and Coke, which he didn’t get to have. When his mother came to visit, she brought him rice and beans.”

SDOH in Health Care and Dietetics
People access health care when they’re sick, but the roots of health are deep and complex. Accordingly, SDOH are a part of newer public health and medical models that take a holistic view of individual patients and population health to enhance patient care and promote better outcomes.24

The idea is that, instead of simply intervening on a clinical level, we need to look upstream to the root causes of good or poor health. In other words, determine the causes of the causes. Unfortunately, dietetics education is behind the curve in this regard. SDOH aren’t part of the Accreditation Council for Education in Nutrition and Dietetics accreditation standards or part of dietetics education, says Anne Lund, MPH, RDN, FAND, director of the Graduate Coordinated Program in Dietetics at the University of Washington in Seattle. While a few of the council’s curriculum standards circle around SDOH, none address them directly.

“We’re really not hitting the nail on the head that there’s more going on here in the person’s environment,” Lund says, adding that while dietetics students in nutrition departments within schools of public health might be exposed to these concepts, other dietetics students probably won’t be. In the latter, the curriculum tends to be based on individual choices, behavior change models, and physiology.

“It’s very much at the individual level and not tied to systemic health risks,” Lund says. “It leaves the answers at ‘The problem is with the individual,’ and ‘If the person has a problem, it’s because they made bad choices.’ Dietetics would be alone among the health care professions in not understanding social determinants of health and why it’s not all individual choice.”

Arevalo says that even though she earned her Master of Public Health, she didn’t learn about SDOH until five or six years ago, applying it first to mental health and then to nutrition and diabetes in the underprivileged populations she serves. “It’s working with the populations I work with that I learned to look at social determinants of health to get these other insights,” she says.

Now, Arevalo is passing along her knowledge. “As a preceptor, when students are doing community rotations with me, I make sure they know about social determinants of health,” she says.

Factoring in SDOH When Working With Clients
A 2009 study that explored the possibility of adding questions about socioeconomic status to the Framingham Risk Scoring system to predict coronary heart disease risk found that the system’s standard questions underestimated risk of those with low socioeconomic status.25 However, dietitians can ask similar questions.

“We need to find out what’s going on in the life of the patient—not just ‘What do you eat?’ but ‘What store do you shop at?’ ‘What work do you do?’ ‘Are you happy or sad when you’re eating?’” Arevalo says. “We need to know everything that affects the food they eat. Access to food means much more to me than where you get your food. It goes far beyond the pantry. The diet isn’t going to change anything if we don’t change the environment of the patient. We need to be detectives. We have to find the gaps and fill in the gaps.”

What can dietitians do when the upstream causes are beyond their influence? “In an individual clinic, as a member of the team, I think they could shut down the shaming and stigmatization that happens,” Lund says—for example, blaming personal choices for diabetes complications. “We are the nutrition professionals in the room, and we know there is more to it.”

“Even if you want to work at the individual level, as much as you can in your community, advocate for support of programs that support disadvantaged populations,” Lund says, citing school lunch, senior aggregate meals, and WIC as prime examples. “Dietitians are usually middle income and middle class—those are the populations that need convincing. There are lots of ways you can support these programs by changing minds.”

— Carrie Dennett, MPH, RDN, CD, is the nutrition columnist for The Seattle Times, owner of Nutrition By Carrie, and author of Healthy for Your Life: A Holistic Guide to Optimal Wellness.


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