If I asked anyone what they thought were the major risk factors for coronary artery disease they might say "high blood pressure, high cholesterol, being overweight, smoking, and diabetes".
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However, they may be surprised to know the environment is a significant risk factor for cardiovascular disease (CVD), which includes coronary artery disease/heart attacks, heart failure, rhythm problems and stroke. In fact, air pollution is the fourth-highest modifiable CVD risk factor (after high blood pressure, dietary risks and high cholesterol) and contributes more to CVD than obesity, smoking, diabetes, and physical inactivity. Temperature extremes are also a significant risk factor for CVD.
Climate Change, through its association with extreme weather (particularly heat) and air pollution worsens CVD and increases deaths. CVD is already the leading cause of death in Australia, and this will increase as the climate crisis continues to unfold.
Heat is the greatest weather-related cause of death, and the number one cause of death during heatwaves is from a cardiovascular event. Extreme heat also increases heart attacks, CVD hospitalisations; and out of hospital cardiac arrest (OHCA). With increasing temperatures, and worsening heatwaves, deaths from CVD will increase.
In 2018, WHO Director-General Dr Tedros Adhanom Ghebreyesus declared: "No one, rich or poor, can escape air pollution. It is a silent public health emergency." Air pollution is considered an invisible killer; WHO estimates about seven million deaths are attributable to outdoor and indoor air pollution, with some recent estimates up to nine million from outdoor pollution alone. More than half of these deaths were due to CVD. More than 20 per cent of global cardiovascular deaths are due to air pollution.
Both short and long term exposure to air pollution increases CVD and deaths; including heart attacks, strokes and heart failure. Like extreme heat, air pollution also increases CVD hospital admissions and OHCA. Acute exposure to air pollution is a trigger for heart attacks, accounting for nearly five per cent of heart attacks worldwide. Worryingly too, is that the risk of CVD with long term exposure to air pollution is increased even at levels considered 'safe.'
In particular, air pollution from burning coal, and traffic exhaust, is more toxic to the heart than air pollution from other sources. Traffic exhaust is one of the most preventable triggers of a heart attack.
In Australia, we may not think we live in a polluted environment, but we do.
Bushfire smoke exposes us to severe air pollution. The smoke from the 2019/2020 bushfires caused air pollution in Canberra to be at levels 22-times more hazardous than those set by WHO. Bushfire smoke is - you guessed it - associated with increased cardiovascular deaths, heart attacks, heart failure and OHCA. The risks of bushfire smoke are further amplified when combined with high temperatures. To add to the burden, climate change has a number of mental health impacts and mental health disorders can increase CVD.
There are an enormous number of things we can do to help both our planet and our heart. Here are just five:
- Have a plant based diet. Burping and farting cows account for the majority of agriculture's greenhouse gas emissions (GHGs), and use more land, water and energy than other foods. A more plant based diet reduces CVD, whilst red and processed meats worsen CVD. This doesn't mean plant foods like french fries, donuts and fried mars bars are good. I would know, I worked in McDonald's for 10 years and did my cardiology fellowships in Canada and Scotland.
- Increase active transport. This is self-transport that involves more activity than using a car eg. walking. If you walk or cycle to work, you have less risk of CVD (including heart attacks) and obesity; whilst also reducing air pollution and GHG emissions. Next time you order food, pick it up on foot and better yet bring your own containers.
- Stop smoking. This is a no brainer - smoking increases heart attacks. Tobacco has significant negative environmental impacts from farming, manufacturing, consumption, waste, pollution and litter.
- Change to renewable energy sources instead of fossil fuel combustion. This will reduce GHGs, improve air quality and reduce CVD. You can change your energy provider to one that only obtains energy from renewable sources, and change from gas to electric appliances.
- Increase Green spaces - This lowers CVD and has multiple other health benefits. Green spaces help mitigate climate change by reducing heat and heat-related illness, and air pollution. Plant more trees to help remove excessive C02.
Our hearts are 'burning' but heart disease is only one of the many health effects of climate change. It is estimated climate change will cost Australia $3.4 trillion by 2070, however the costs to health will be immeasurable. The recent IPCC 2021 report signals climate change as a code red for humanity. We only have one heart, and there is no planet B. Let's be proactive, positive, and extinguish the flames together.
To hear more about how climate change impacts your health, watch Dr Foo's online talk from the Eco Living Festival. The festival has more than 30 free online webinars about living more sustainably. To watch the webinars, visit www.youtube.com/user/RandwickCouncil/playlists
- Dr Fiona Foo, Sydney-based cardiologist.
