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Understanding Environment, Climate as Social Determinants of Health

Some healthcare stakeholders are looking at both natural and built environment, as well as climate change, as emerging social determinants of health.

As the medical industry continues to understand how social determinants of health impact overall wellness, the topics of environment and climate change have come into view.

SDOH specifically refer to the environments in which individuals live, work, and play. Currently, most stakeholders are zooming in on factors like houselessness or food insecurity as leading SDOH impacting health. But a look at natural and built environments—green space, water quality, neighborhood violence—can illuminate patient relationships with other SDOH and provide insights into health outcomes.

Said otherwise, patient wellness depends on more than having a house to live in, food to eat, and transportation to get places. The physical spaces we live in, and the quality of the built and natural elements in those spaces, also play a key role in achieving better health.

Environmental factors, climate change

Environment—meaning the natural geographic and climate elements in which an individual lives—has a considerable impact on health. According to Healthy People 2030, the three biggest environmental drivers of health include water quality, air pollution, and extreme heat.

“Poor water quality places the public’s health at risk,” Healthy People 2030 wrote. “For example, groundwater sources used for drinking water and crop irrigation may become contaminated.”

Infrastructure can also lead to poor water quality; the Flint water crisis serves as one contemporary example.

“Chronic exposure to outdoor air pollutants, such as ozone and fine particulate matter, increases the risk of cardiovascular disease and death, including death from lung cancer,” Healthy People 2030 added. “People spend a substantial amount of time indoors for work, school, and sleep, so indoor air pollutants can also damage health.”

Finally, extreme heat can cause significant health impacts. Extreme heat can lead to heatstroke, and for individuals experiencing homelessness or those living in insecure housing that does not regulate air temperature, those temperatures can become dangerous.

In January 2022, researchers from the University of California San Diego reported that heatwaves result in a spike in emergency department visits among the housing insecure. A two-day heatwave increased the odds a housing insecure person would visit the ED by a factor of 1.29. The longer the heatwave, the higher the odds of an ED visit.

Climate change exacerbates all of this, many experts agree. Climate change has led to more drastic weather and climate events, as well as poorer water and air quality.

“Climate change is the single biggest health threat facing humanity, and health professionals worldwide are already responding to the health harms caused by this unfolding crisis,” the World Health Organization writes on its website.

WHO said the health risks associated with climate change can be wide-ranging and include:

  • Injury and mortality from extreme weather events
  • Heat-related illness
  • Respiratory illness
  • Water-born illness and other water-related health impacts
  • Zoonoses, diseases that can be transmitted from animals to humans
  • Vector-borne diseases
  • Malnutrition or food-borne diseases
  • Noncommunicable diseases
  • Mental and psychosocial health

Taking action on environment, climate change

The American Academy of Pediatrics has argued for addressing climate change as a key social determinant of health, remarking on the way climate change can ultimately harm health and how that trend is slated to get worse as today’s children age into adulthood.

“The child health impacts are numerous and include worsening asthma and allergies; physical trauma from disasters; mental health symptoms, including posttraumatic stress disorder after disasters and anxiety about the future; increased exposure to infectious diseases; and lack of access to adequate food and clean water,” AAP wrote in a 2022 paper.

“Viewing climate change as an SDOH could potentially help coalesce a large group of ideologically different stakeholders around the common goals of decreasing health care costs and improving child health,” the group added.

That said, climate change and environment are unique social determinants of health in that they don’t have tangible near-term solutions and many of the fixes, like lower carbon emissions, might be better addressed at a state or federal policy level.

That said, AAP wrote that clinicians wield key patient education power. While more work needs to be done to assess parent preferences for discussing environment and climate change during the clinical encounter, AAP recommended discussing things like disaster preparedness.

“The pediatric community should also familiarize itself with actions individuals, families, and communities can take to both decrease carbon emissions and reduce the health impacts of climate change and incorporate these recommendations during routine anticipatory guidance,” the group advised. “Pediatric providers may also consider having developmentally appropriate materials available to support parents who are trying to talk with their children about climate change.”

Patient education will be important even in general adult care, according to an Insights report from NEJM Catalyst. Nearly seven in 10 healthcare providers said it’s very or extremely important that their organization take action on climate.

And although providers perceive patient interest as somewhat lower, there is still a duty for patient engagement and education, according to Renee N. Salas, MD, MPH, MS, is Affiliated Faculty at the Harvard Global Health Institute, a Yerby Fellow at the Center for Climate, Health, and the Global Environment at the Harvard T.H. Chan School of Public Health, who wrote the NEJM Catalyst report.

“There’s an enormous opportunity for health professionals to help patients see the connections between climate change and their health,” wrote Salas, who is also a practicing emergency medicine physician at Massachusetts General Hospital and Harvard Medical School. “This is fundamentally driven by our mission to prevent harm and improve health. As patients see these connections, climate change becomes personal and action becomes a prescription for improving health.”

Community health partnerships may also be helpful here. Healthcare organizations, especially hospitals, usually serve as anchor institutions in communities and can leverage their wide reach by turning the conversation to climate change action.

Per the NEJM Catalyst report, most healthcare organizations are working on updated disaster planning, organization vulnerabilities, energy conservation programs, and sustainable waste management. However, more and better data about climate change, as well as funding, will be key to continuing these efforts, the report indicated.

Built environment

Built environment, or human-made structures and surroundings, likewise has a direct impact on patient health. Built environment can be related to transportation access, travel distance and access to care, education quality and attainment, housing security and quality, and neighborhood safety.

“Many people in the United States live in neighborhoods with high rates of violence, unsafe air or water, and other health and safety risks,” according to Healthy People 2030. “Racial/ethnic minorities and people with low incomes are more likely to live in places with these risks. In addition, some people are exposed to things at work that can harm their health, like secondhand smoke or loud noises.”

These factors all have a downstream impact on patient health. Individuals living in neighborhoods with high levels of secondhand smoke, for example, may experience poorer air quality, as might individuals living in urban areas.

Neighborhoods with high occurrence of interpersonal violence, places with limited access to well-funded schools, and places that are located in healthcare deserts also impact patient wellness.

For example, 2019 data published in Health Affairs found that kids exposed to moderate or high neighborhood violence went on to have mental and physical health challenges, with the greater the childhood exposure the worse the health impacts. It is also worth mentioning the link between neighborhood violence, gun violence, and mortality.

Taking action on built environment

Like so many environment SDOH factors, addressing challenges with the built environment will require policymaking on the local, state, or federal level. For example, adding bike lanes and sidewalks may make a city more navigable for individuals, while also improving activity levels in a community.

February 2022 figures published in Endocrine Reviews found that cities deemed “walkable” had higher overall individual activity levels as well as lower occurrence of diabetes and obesity. The study found that the prevalence of obesity among adults in walkable neighborhoods was 43 percent, compared to 53 percent for those in neighborhoods with lower walkability.

Policy initiatives that focus on housing, injury prevention, physical activity, respiratory health, sensory or communication disorders, tobacco use, transportation, and employment quality and opportunity may also be helpful.

Access to greenspace

Greenspace, or the trees, grass, or other vegetation in an otherwise urban environment, could arguably fall into the natural or built environment categories. But it’s worth exploring greenspace individually as more research investigates the link between greenspace and health.

In April 2022, researchers from the Boston University School of Public Health found that more greenspace could improve cognitive function in middle age and ultimately stave off cognitive diseases like Alzheimer’s and dementia.

Particularly, the researchers said access to greenspace around one’s home and neighborhood could improve processing speed, attention, and overall cognitive function. This could be due to a decrease in depression, the researchers posited.

“Some of the primary ways that nature may improve health is by helping people recover from psychological stress and by encouraging people to be outside socializing with friends, both of which boost mental health,” Dr. Marcia Pescador Jimenez, study lead and corresponding author, and assistant professor of epidemiology at BUSPH, said in a statement about the study.

City planners and urban developers may consider the role vegetation and greenspace play in improving overall population and public health, the researchers recommended. Paying attention to where greenspace is built—for example, in typically underserved neighborhoods—could help achieve health equity.

Greenspace has also played a role in cutting down on some of the COVID-19 racial health disparities (although to be clear, those disparities remain stark as of publishing time). In an assessment of 135 of the most urbanized parts of the US, the researchers saw a reduction in COVID racial health disparities when there was more greenspace in a given area.

Although greenspace, like other environmental factors, is primarily a local or federal policymaking issue, healthcare providers can take matters into their own hands during patient communications. Providers may recommend or “prescribe” more time in the park, for example, for patients with certain healthcare problems.

That said, across all environmental issues, partnerships between healthcare experts and policymakers will be critical. At publishing time, the Department of Health & Human Services had established an Office of Health Equity & Climate Change, although by April 2022 the office was just in its nascency.

Still, HHS said it intends the office to help the industry embrace environmental factors as social determinants of health.

Correction 05/03/2022: A previous version of this article misstated findings from the Endocrine Reviews study. This article has been updated to reflect 53 percent obseity rates in low-walkability neighborhoods and 43 percent obesity rates in high-walkability neighborhoods.

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