Measuring and Addressing the Environmental Factors That Impact Social Determinants of Health

Social determinants of health (SDOH) significantly impact health outcomes in individuals and fuel health disparities between different populations, but quantifying SDOH and addressing the factors that allow disparities to persist can be difficult. In a symposium at the 2023 American Thoracic Society (ATS) International Conference, experts discussed environmental factors that impact SDOH and may serve as potential targets for interventions to mitigate SDOH.

SDOH are the conditions in which individuals are born, live, work, and age. Collectively, these conditions—including factors like socioeconomic status, work conditions, education, health care access, and more—have a substantial impact on health outcomes. Environmental factors play a significant role in overall health and respiratory health, as experts discussed in a presentation titled, “Can Environmental Interventions Change the Social Determinants of Health?”

John R. Balmes, MD, ATS fellow and professor of medicine emeritus at the University of California San Francisco and professor of environmental health sciences emeritus at the UC Berkeley School of Public Health, kicked off the session with a look at how SDOH are quantified.

“The bottom line is you can't assess whether an intervention works in terms of social determinants or structural determinants of health if you haven't measured those before and after the intervention,” Balmes said.

The issue is that there is little consensus on how SDOH are measured, with variation around categories that are evaluated in research.

Balmes highlighted a literature review conducted by researchers in Colombia and published in the journal Entramado. The review, which included 27 scientific studies, found that the most evaluated determinants were the health system, education, and economic income and housing. Demographics such as age, gender, and ethnicity were assessed in only 41% of the studies. Overall, the study authors concluded that the measurement of SDOH had been limited and standardized tools are limited.

Another review assessed 9 SDOH measurement tools from 56 publications and found that there was little standardization among them, reiterating a need for specific, accurate indicators used to measure SDOH.

This can be difficult in certain populations, he noted, recalling a study of lung function in smoke-exposed Guatemalan children that he worked on. In this population, an asset index based on possession of items such as a television, motorcycle, or cell phone was the only type of scale they found to vary across more than 500 families in the analysis.

To conclude, he stressed the importance of measuring SDOH in the evaluation of health interventions in the United States and across the globe. While there is agreement on some of the categories that must be measured, standardization is needed.

Isaretta L. Riley, MD, MPH, a pulmonologist and assistant professor of medicine at Duke University in Durham, NC, spoke to environmental context and barriers to asthma inhaler use in high- vs low-income countries, as well as patient-reported barriers to treatment in her practice and approaches to reduce such barriers.

Riley and colleagues conducted a review of international barriers to asthma medication adherence mapped on the theoretical domains framework, which is a behavior change theory that identifies reasons why someone wouldn’t do a certain behavior.

The most common barriers to treatment adherence were beliefs about the consequences of not taking medicine, knowledge deficits (such as not knowing when to take medication), and environmental context and resources such as cost.

A country’s socioeconomic and political context also has a substantial impact, with factors such as universal health care or a lack thereof, or even policies such as those banning indoor smoking at a restaurant, for example, all come into play when it comes to asthma medication adherence and symptom exacerbation, Riley said. A patient’s individual socioeconomic position also factors in, and this can be determined by factors such as social class, gender, sexual orientation, race, and education.

“Barriers may vary with a country's sociopolitical context, and future inherent intervention should account for the sociopolitical context and transit barriers unique to that population,” she said. Factors such as neighborhood violence, for example, may limit a patient’s ability to exercise outdoors or obtain medication.

In her own practice, Riley aims to tailor her interventions with SDOH in mind, and much of her research focuses on the biobehavioral and psychosocial aspects of barriers to care.

“I pair my biobehavioral interventions with interventions that address unmet socioeconomic needs,” she said. “We can assess your social determinants of health in our health system, and then do social prescribing or connect you with community resources to address those needs.”

Obianuju B. Ozoh, MBBS, MSc, a pulmonologist and researcher at the University of Lagos in Nigeria and ATS fellow, highlighted the impact of household energy sources in low- and middle-income countries on health and perpetuation of poverty.

Household cooking fuels such as kerosene, charcoal, and liquefied petroleum gas (LPG) are still widely used in low- and middle-income countries. Many “stack” their fuel while cooking, using multiple types of fuel combinations in the same home, she noted.

In homes where biomass is burned for fuel, research has found that both children and adults experience increased respiratory symptoms. Exposure to household air pollution exposure has been tied to lower lung function, which may lead to higher frequency of pneumonia and repeated pneumonia, Ozoh said. These effects also extend to children in households.

“These children who have severe asthma in childhood and repeated episodes of pneumonia usually also have exposures perinatally, which could be from household energy and tobacco use,” Ozoh said. “And there's also another trajectory where children have low lung function, which is also associated with perinatal exposures.”

A lack of access to adequate clean energy source also perpetuates the “poverty trap,” Ozoh said. Those with poor health due to environmental exposure such as household air pollution tend to have lower wages and cannot build wealth to pay for measures to improve their health, such as cleaner fuel. While buying cleaner fuel in bulk is cheaper, most families cannot afford the upfront cost.

Energy insecurity is an issue that affects households globally, including in the United States, and Diana Hernandez, PhD, a researcher at Columbia University in New York, focused her talk on interventions that may mitigate the health effects of energy insecurity.

“We also know that energy insecurity is patterned by social vulnerability, such that households with children, renters, Latino households, Black, mixed-race, other race households, and low-income groups are more likely to be energy insecure than others,” Hernandez noted. These populations are also more likely to experience household maintenance defects.

These individuals are at a greater risk of lacking heat or air conditioning at home. During extreme heat or cold, a lack of temperature regulation in the home can put these individuals at risk of exacerbations. At least 350 deaths are exacerbated by heat each year in New York City, and 100% of the people who died from heatstroke had no air conditioning at home, Hernandez said.

The ambitious Get Cool NYC program provided air conditioning units to 73,000 homes in New York City, and a collaborative effort between the New York City Department of Health, the New York City Housing Authority, and WE ACT for Environmental Justice assessed the outcomes among a sample of residents who participated and residents who did not.

When asked if they were able to stay at home to stay cool in the summer of 2020, those that received an air conditioning unit reported a 19% increase vs prior to receiving the air conditioning unit. For those who did not receive a unit, there was only a 1% increase. Individuals who did not participate were more likely to report feeling sick due to the heat.

Those facing energy insecurity reporting impacts on the management of pre-existing chronic health conditions such as asthma or hypertension, and many reported hesitance to engage in social activity in their home, which could potentially impact social isolation.

Adali Martinez, MD, MPH, a pulmonary fellow at the University of California San Francisco, highlighted the potential of screening for unmet social needs and community linkage programs to mitigate asthma disparities in the United States.

Martinez emphasized the impact of structural racism and discriminatory policies that forged the differential distribution of wealth and SDOH that still impact marginalized populations.

“This has a direct effect and indirect effect and asthma, not only in exposing you to things like indoor and outdoor pollutants, but also in increasing the risk of financial burdens and unmet social needs that then influence your ability to attend for your health,” Martinez said.

SDOH such as running out of food or receiving food stamps have been associated with increased odds of asthma-associated symptoms such as nighttime coughing and wheezing with exercise.

“The social determinants of health, we know from many studies, are associated with asthma,” she said. “So now what do we do? Well, just like in biological precision medicine, we have molecular markers that help guide our treatments in asthma. Why can't we have the same type of screening or markers to determine which of these upstream determinants of population health affect a family or a neighborhood?”

Her lab created a screening tool, the Pediatric ACEs and Related Life Events Screener, a 17-item tool which is now implemented statewide in pediatric offices in California. It includes the traditional 10 markers of adverse childhood experiences, as well as questions about housing and food.

In a study, Martinez and colleagues found that children with asthma had very high rates of the related life events and adversities, with 86% reporting at least 1 and about half of participants reporting 4 or more. The odds of severe wheezing and wheezing with exercise increased with each additional reported adversity.

While the existence of disparities and the negative impacts of SDOH are known, the question of whether interventions can mitigate these environmental effects was the final topic addressed in the presentation.

To close out the session, Peggy S. Lai, MPH, MD, a researcher at Massachusetts General Hospital in Boston and an ATS fellow, shared findings of a study conducted in rural Uganda where kerosene or biomass are used for fuel in many instances, especially among individuals living in poverty.

In a randomized solar lighting intervention trial, Lai and colleagues provided solar lighting systems to participants and used sensors to see how much the light was used. The intention was to find out if this intervention would reduce indoor air pollution and how often participants would use the solar light system.

By the end of the study, kerosene light use was almost eradicated in the homes that received a solar light setup with fixtures indoors and outside of their homes for security.

Solar light also significantly reduced light rationing, which was an issue for households that could not always afford to buy more fuel when needed. Houses with solar light also became hubs for social activity, including children doing schoolwork. At least one family noted that children’s school performance improved because they could do their homework at night, whereas they often had to forego it in favor of saving money on fuel before the solar light intervention.

“We found that uptake for this whole idea [[of engine[[ was quite high, and we think is likely explained by the wide-ranging impact within the social determinants of health,” Lai said.

While qualitative studies such as the solar light intervention are key for generating hypotheses, standardized ways to measure SDOH and ways are needed, Lai noted. With a survey or consistent way of measuring SDOH, these issues could be addressed preemptively.