‘An existential issue’: Wealth, race and health inequities exacerbated by climate change

Elizabeth Tung, MD, MS, Assistant Professor of Medicine, focuses her research primarily on how race and wealth contribute to health inequities. The line to climate change may not be immediately obvious, but the relationship is there. She points to a recent lettuce shortage: “Lettuce got more expensive because of issues related to climate change,” she said. “As the climate changes, who will be able to afford nutritious food, and what does that mean for the health of our communities? There’s a real connection there.”

She studies health disparities caused by social inequity and wonders how they can be exacerbated by the pressures of climate change. “We know that people with lower income, who are experiencing racism or violence, have much higher allostatic load than those who are not facing the same stressors,” she said. “That chronic activation of stress responses can increase stress hormones like cortisol, and over time that can directly impact health. Chronic stress contributes to a host of health problems, including cardiovascular disease, which is the largest contributor to the racial mortality gap.”

Climate change is yet another source of inequity; those with the fewest resources and who are the most vulnerable are disproportionately affected by it, in everything from the rising cost of food to lack of secure shelter from extreme weather events to increased risk of exposure to pollution and infectious disease.

An area of particular focus for Tung is the intersection between violence and health inequity. “Violence is an outcome of inequity,” she said. “More than medical and mental healthcare, patients who are affected by violent injury will often say they need access to economic and legal resources. For example, eviction can be equally or more toxic to a person than not being able to fully rehab an injured leg. The chronicity of stress related to housing instability has major downstream effects on people’s lives and well-being.” Add to that the effects of climate change on housing, which have already exacerbated the affordable housing crisis and increased housing damage due to flooding and other natural disasters. These climate challenges will not only increase existing health inequities, but will

Inequities exacerbated by climate change

Research has indicated that poorer countries closer to the equator have suffered economic loss due to climate change, while wealthier, northern countries have in some increase the strain on an already struggling healthcare system, making it ever more difficult for those most burdened by the effects of climate change to access the resources they need to survive it. The question isn’t so much whether these issues will get worse in the future, but rather how to address them.

“There’s a big movement in the health sciences to place a greater emphasis on the social determinants of health, but this is an existential issue,” said Tung. “Most of the solutions currently available to us rely on addressing the specific needs of an individual person or patient, but they don’t provide opportunities for systemic change. If wealth inequality continues to worsen, it will become even more difficult to sustain the services that we are able to offer. It’s a never-ending cycle.” ways benefited. Poorer populations are less likely to have access to insurance and healthcare resources to bounce back from extreme weather events and infectious diseases, or to have the finances to keep up with the rising cost of food or to relocate from areas that are hit the hardest by changing weather patterns.

How our environment affects us: Environmental exposures are changing our genes

When she arrived in Beijing as a new university student, Yu-Ying He, PhD, was struck by the contrast to the rural area where she grew up and especially the amount of pollution in the air, a major issue during that time.

“It constantly made me think about how different environments can lead to differences in our health, even when we’re working with a very similar genome,” she said. “It made me wonder how the biology works when we’re exposed to certain chemicals or radiation or even biological factors, like a virus. These things can put an imprint on our bodies, but we don’t always know what the long-term effects will be.”

Her current research focus is on understanding how exposure to UVB radiation and arsenic affect the role of RNA methylation in cancer development. She studies epitranscriptomics the modifications made to RNA that affect how and which proteins are produced within our cells.

She sees a connection between her work and climate change because it all comes back to one thing: human decisions. “Climate change and pollution are deeply connected,” said He, Professor of Medicine. “The chemicals we make and release into the atmosphere are a huge contributor to climate change. Humans are very innovative. However, we humans also create these unexpected and unintended consequences, but because it takes years for the toxic response to appear, we don’t realize it right away.”

Perhaps the most obvious connection between her work and climate change is one that has been mostly successfully addressed by policy change. Those who grew up in the 1990s likely remember learning about the “hole in the ozone layer,” caused by human use of chemicals such as chlorofluorocarbons. Ozone layer depletion allows more UVB rays to reach the planet’s surface, affecting everything from agriculture to marine ecosystems to cancer rates in humans. Thanks to international agreements reducing the use of chlorofluorocarbons in the 1980s, the ozone hole is slowly shrinking; but in the meantime, its effects still remain.

One of the challenges He faces is determining which RNA changes are significant. “We’ve seen RNA modifications in response to UV stress a few times, but we don’t really know what the implication of that is,” she said. “There are classical responses, such as DNA damage, but epitranscriptomics is still in its infancy. We are probably one of the few groups looking at the unique connection between epitranscriptomics and the environment, which is helping us understand how dysfunction in the machinery caused by environmental exposures contributes to diseases.”

While the ozone layer is slowly repairing itself, reducing the risk of UVB exposure, other environmental changes are having notable effects on our health. Rising global temperatures mean that communities are experiencing longer and more intense heat waves, which are associated with preterm birth and increased risk of dehydration, blood clots, heart attacks and seizures. These are most likely to affect the vulnerable and immunocompromised, including older adults and young children. Changing weather patterns increase the presence of pollutants in the air, including wildfire smoke and allergens such as molds and pollens. These can directly impact the health of those with such conditions as asthma and, over the long term, contribute to increased rates of health problems across communities.