A new field of medicine, dubbed ‘climate cardiology,’ is necessary to “protect patients and the planet” at the same time, researchers argue in a commentary published in the journal BMJ Global Health.
The nascent field is at the intersection of two major public health challenges: climate change, which contributes to a variety of health risks ranging from heat exposure to malnutrition, and cardiovascular disease, the leading cause of death worldwide.
Climate action is often portrayed as being in conflict with or coming at the expense of human well-being. But the researchers show this is not the case by laying out several different ways in which climate change puts cardiovascular health at risk.
The effects are both direct and indirect: for example, heat waves can trigger heart attacks and strokes, with an estimated 93,000 cardiovascular deaths caused by heat exposure in 2019. And extreme weather events caused or worsened by climate change can also damage health care facilities and interrupt people’s ability to access medical care.
“Increasingly, environmental risk factors are seen as a risk to cardiovascular health,” says Michael Hadley, a cardiologist at Mount Sinai Hospital in New York, New York and one of the commentary’s authors. “The best evidence for this is probably for air pollution, which is now listed by the American Heart Association as a preventable risk factor for cardiovascular outcomes.”
Air pollution can be a consequence of the fossil fuel burning that is the major cause of climate change, and can also arise from climate-change-induced wildfires. This environmental risk factor is responsible for an estimated one-fifth of global deaths from cardiovascular disease.
Climate change also contributes to crop failures and rising poverty, especially in low-income countries. These factors impoverish people’s diets, reducing access to heart-healthy foods such as fish and fresh fruit and vegetables. There’s also evidence that climate change makes certain staple grain crops less nutritious.
Hadley and his colleagues also identified six actions that could both improve cardiovascular health and mitigate climate change. Burning fossil fuels is the largest source of planet-warming carbon dioxide and a type of health-damaging air pollution known as PM2.5. Transitioning to clean energy “therefore provides the greatest opportunity to protect both the planet and cardiovascular health,” the researchers write.
By eating less red meat and more plant-based foods, people can improve their cardiovascular health and shrink their carbon footprint at the same time. Diets high in red meat were linked to 738,000 cardiovascular deaths in 2019, and greenhouse gas emissions associated with diets high in red meat are about twice those of vegetarian diets. Shifting mobility away from cars and toward active transport similarly has simultaneous benefits for cardiovascular and climate health.
Fourth, by expanding green spaces cities can remove carbon dioxide from the air, mitigate urban heat, and provide people with areas to exercise and reduce stress. Indoor cookstoves that burn coal or biomass are common in many low-income countries, and replacing these with clean cooking stoves would also improve cardiovascular health while reducing GHG emissions.
Finally, health care workers and health system administrators can make efforts to reduce the carbon footprint of health care. The health care sector is responsible for 4.4% of GHG emissions and 2.8% of particulate matter air pollution globally.
Climate cardiology is also likely to change the daily practice of medicine. “Clinical cardiologists can begin to incorporate the management of environmental risk factors like air pollution into their clinical practice,” Hadley says, for example by screening patients for exposure to pollution or wildfire smoke, and recommending interventions such as using an indoor air purifier or personal respirator.
More studies are needed to get a better handle on which patients are most at risk from environmental exposures, and which interventions work best to protect them. “We believe that, more and more, it will be the clinician’s role to help create a tailored plan to protect high-risk patients from environmental exposures,” Hadley adds.
Source: Hadley M.B. et al. “Climate cardiology.” BMJ Global Health 2022.
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