Environment, Climate and Cardiovascular Health: What We Know, What We Need to Know and What We Need to Do.

Climate change is now considered the biggest threat to the human population of the 21st century [[1]Watts N. Amann M. Arnell N. Ayeb-Karlsson S. Belesova K. Berry H. et al.The 2018 report of the Lancet Countdown on health and climate change: shaping the health of nations for centuries to come.Lancet (London, England). 2018; 392: 2479-2514Abstract Full Text Full Text PDF PubMed Scopus (479) Google Scholar], and we are faced with a situation where environment, climate and health are interconnected. Human health is reliant on planetary health. In Australia, the Black Summer bushfires (2019–2020) burned more than 24 million hectares of Australian bushland. Recent datasets of satellite imagery of burned areas, observations of climate and weather, and simulated fuel loads have since been confirmed to be part of a clear trend of worsening fire weather and ever-larger forest areas burned by bushfires [[2]Canadell J.G. Meyer C.P. Cook G.D. Dowdy A. Briggs P.R. Knauer J. et al.Multi-decadal increase of forest burned area in Australia is linked to climate change.Nat Commun. 2021; 12: 6291Crossref Scopus (79) Google Scholar]. Intense fires in the Amazon also captured global attention in 2019 for the destruction of natural ecosystems and smoke production in the region. Both bushfires raged through the colloquial ‘lungs of the world’ in 2020, with widespread regional public health consequences, including premature death related to smoke pollution [[3]Marlier M.E. Bonilla E.X. Mickley L.J. How do Brazilian fires affect air pollution and public health?.Geohealth. 2020; 4e2020GH000331Crossref Scopus (11) Google Scholar]. When the Call for Papers for this Special Edition on Environment, Climate and Cardiovascular Health went out in 2021, we could not know what the next disaster in our region would be. Then, in Australia in 2022, we experienced severe and widespread flooding. These and other extreme weather events are anticipated to continue and indeed increase in response to climate change [[4]Magdy J.S. Adikari D.H. Gray R.C. Alexopoulos C. Jepson N.S. Fire and flood: the cardiovascular impact of natural disasters — A regional New South Wales experience.Heart Lung Circ. 2023; 32: 8-10Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. As 2023 begins, the contributions in this Special Edition of Heart Lung and Circulation share a common message—we know a lot, we need to learn a lot more, and there is lot (more) we can all do to prevent, ameliorate, and manage the cardiovascular effects of these environmental and climate disasters. Cardiovascular disease (CVD) is the leading cause of death globally [[5]World Health Organization. 2021Cardiovascular diseases (CVDs) Key Facts.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)Google Scholar]. Importantly, clinicians, policy makers, and stakeholders need to be cognisant that vulnerable populations are at greater risk from sudden or extreme changes in environmental conditions. As an example, Magdy and colleagues highlight the cardiovascular consequences of extreme weather conditions in Port Macquarie, NSW, Australia [[4]Magdy J.S. Adikari D.H. Gray R.C. Alexopoulos C. Jepson N.S. Fire and flood: the cardiovascular impact of natural disasters — A regional New South Wales experience.Heart Lung Circ. 2023; 32: 8-10Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. They point out that natural disasters have a disproportionately greater impact on individuals living in regional and remote areas, not only in terms of property damage but also in effects on public infrastructure and access to services, which exacerbated existing health disadvantages. In a Call to Action from the Cardiac Society of Australia and New Zealand (CSANZ) Nursing Council, Inglis and colleagues also identify groups who may be unable to safeguard against the shock of climate events or to engage in critical actions that reduce impact on their cardiovascular health, including First Nations peoples, people who are elderly and frail and those from low-socioeconomic status households [[6]Inglis S.C. Ferguson C. Eddington R. McDonagh J. Aldridge C.J. Bardsley K. et al.Cardiovascular nursing and climate change: a call to action from the CSANZ Cardiovascular Nursing Council.Heart Lung Circ. 2023; 32: 16-25Abstract Full Text Full Text PDF Scopus (2) Google Scholar]. The Call states that such groups need targeted preventive actions and support so that they can be protected from potentially avoidable harm. This Special Edition highlights the importance of health professionals working in cardiovascular health taking leadership and in understanding how their care of patients can be part of the problem. Specifically, Szirt and colleagues write that the healthcare sector contributes to nearly 5% of global carbon emissions [[7]Szirt R. Monjur M.R. McGovern L. Charlesworth K. O'Connor S. Weaver J.C. Coughlan J.J. Environmental sustainability in the cardiac catheter laboratory.Heart Lung Circ. 2023; 32: 11-15Abstract Full Text Full Text PDF Scopus (2) Google Scholar], and that the exponential growth of medical waste poses a significant challenge to environmental sustainability. Szirt et al. outline how healthcare workers in cardiac catheter labs can make a meaningful change to their practice and contribute towards a more sustainable future by taking advantage of opportunities to reduce waste [[7]Szirt R. Monjur M.R. McGovern L. Charlesworth K. O'Connor S. Weaver J.C. Coughlan J.J. Environmental sustainability in the cardiac catheter laboratory.Heart Lung Circ. 2023; 32: 11-15Abstract Full Text Full Text PDF Scopus (2) Google Scholar]. These include adopting a “lean” mentality, “The Five R-Concept”—to Reduce, Reuse, Recycle, Rethink and Research, and avoiding the use of unnecessary equipment and material [[8]Kagoma Y.K. Stall N. Rubinstein E. Naudie D. People, planet and profits: the case for greening operative rooms.CMAJ. 2012; 184: 1905-1911Crossref PubMed Scopus (82) Google Scholar]. This approach may well conflict with single-use device policy and practice but nevertheless represents a challenge that we need to confront. Ambient air pollution is recognised to be a significant contributor to the burden of CVD and mortality. However, there is much yet to be understood about the connection between air pollution and CVD [[9]Franklin B.A. Brook R. Arden Pope 3rd, C. Air pollution and cardiovascular disease.Curr Probl Cardiol. 2015 May; 40: 207-238Crossref PubMed Scopus (327) Google Scholar], and several reports in this Special Edition help further our understanding. A systematic review of more than three decades of research reported in multiple databases by Fathieh and colleagues found that particulate matter <2.5 μm (PM2.5) was the most studied pollutant, followed by particulate matter between 2.5 μm–10 μm (PM10), nitrogen dioxide (NO2) and ozone (O3) [[10]Fathieh S. Grieve S.M. Negishi K. Figtree G.A. Potential biological mediators of myocardial and vascular complications of air pollution—A state-of-the-art review.Heart Lung Circ. 2022; 32: 26-42Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. The researchers identified key activated pathophysiological pathways that lead to myocardial and vascular injury in response to air pollutants—activation of systemic and local inflammation, oxidative stress, endothelial dysfunction, and autonomic dysfunction. In an original research article, Lankaputhra and colleagues suggest that an imbalance in cardiac autonomic function is a key mechanism of the adverse cardiovascular effects of bushfire smoke [[11]Lankaputhra M. Johnston F.H. Otahal P. Jalil E. Dennekamp M. Negishi K. Cardiac autonomic impacts of bushfire smoke — A prospective panel study.Heart Lung Circ. 2023; 32: 52-58Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. They found that exposure to bushfire smoke (planned burning) in two rural towns in Victoria, Australia, was associated with reduced overall and long-term heart-rate variability (measured with repeat 24-hour Holter electrocardiography). In a Japanese case-crossover study, Zhao and colleagues aimed to determine the associations between the incidence of acute cardiac events and both gaseous (carbon monoxide, nitrogen oxides, photochemical oxidants and sulfur dioxide) and particulate matter [[12]Zhao B. Johnston F.H. Salimi F. Oshima K. Kurabayashi M. Negishi K. Short-term exposure to sulfur dioxide and nitrogen monoxide and risk of out-of-hospital cardiac arrest.Heart Lung Circ. 2023; 32: 59-66Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. They found that short-term exposures to sulfur dioxide and nitrogen oxides are associated with an increased risk of out-of-hospital cardiac arrest. In an Iranian ecological study, Mohammadian-Khoshnoud et al. found that responses to air pollutants differed between men and women in terms of hospitalisation for acute myocardial infarction, indicating that gender-stratified analysis is important [[13]Mohammadian-Khoshnoud M. Habibi H. Manafi B. Safarpour G. Soltanian A.R. Effects of air pollutant exposure on acute myocardial infarction.Heart Lung Circ. 2023; 32: 79-89Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. In India, seeking to detect regional vulnerabilities and provide forewarnings, Sajith Kumar et al. observed that economically developed states may be contributing a greater share of air pollution-attributed CVD [[14]Sajith Kumar S. Sasidharan A. Bagepally B.S. Air pollution and cardiovascular disease burden: changing patterns and implications for public health in India.Heart Lung Circ. 2023; 32: 90-94Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. On a reassuring note, it is hoped this Special Edition will deepen awareness and understanding and subsequently assist in promoting effective actions that combat the causes and effects of adverse cardiovascular health outcomes related to the environment and climate. In a prospective randomised crossover trial protocol, Barbhaya and colleagues hypothesise that the use of personal protective aids (such as home indoor air purifiers and N95 masks) could decrease blood pressure in people with hypertension and fasting blood glucose levels in those with diabetes [[15]Barbhaya D. Tran J. Khetan A. Hejjaji V. Jain S. Chan C. Goel A. Rationale and design of a study to test the effect of personal protective aids on hypertension and diabetes in people living with high levels of air pollution – study protocol.Heart Lung Circ. 2023; 32: 124-130Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. These authors hypothesise their study will ultimately demonstrate whether personal protective aids can be a viable adaptation measure for people living with hypertension and diabetes in areas with a high burden of air pollution. The global COVID-19 pandemic has caused unparalleled disruption and seems ubiquitous in its presence [[16]World Health OrganizationCoronavirus disease (COVID-19) pandemic. 2022.who.int/emergencies/diseases/novel-coronavirus-2019Google Scholar]. In this edition, Cowie and colleagues remind us that the particles dispersed in our environment also include the spread of aerosolised respiratory particles that can lead to the transmission of diseases such as COVID-19 [[17]Cowie B. Wadlow I. Yule A. Janssens K. Ward J. Foulkes S. et al.Aerosol generation during high intensity exercise — Implications for COVID-19 transmission.Heart Lung Circ. 2023; 32: 67-78Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. The results of their prospective, observational cohort study provide a caution for readers: wearing a surgical face mask while exercising indoors at high intensity on a cycle ergometer may only have a limited effect on reducing the spread of such particles. Measures for safer indoor exercise need to emphasise distance and airflow and not rely solely on mask-wearing. Looking forward, Poon and colleagues aim to assist in developing a nationwide climate-health projection model to improve health care resource allocation for the combined effects of temperature and humidity [[18]Poon E.K.W. Kitsios V. Pilcher D. Bellomo R. Raman J. Projecting future climate impact on national Australian respiratory-related Intensive Care Unit demand.Heart Lung Circ. 2023; 32: 95-104Abstract Full Text Full Text PDF Scopus (1) Google Scholar]. Their modelling, based on multiple datasets, demonstrated that different carbon emission climate scenarios would lead to very different projected demands for respiratory disease-related lengths-of-stay in intensive care units. In brief, the highest carbon emission climate scenario led to an almost two-fold higher demand for intensive care. At the population-level, Chaseling and colleagues write of the importance for heat–health advice to be evidence-based [[19]Chaseling G.K. Morris N.B. Ravanelli N. Extreme heat and adverse cardiovascular outcomes in Australia and New Zealand: what do we know?.Heart Lung Circ. 2023; 32: 43-51Abstract Full Text Full Text PDF Scopus (2) Google Scholar]. They call for the development and dissemination of scientifically supported public policy advice to mitigate the adverse health outcomes of extreme heat for vulnerable populations. Feng and colleagues advise that ‘urban reforestation’, including an increase in tree canopy cover, may protect cardiovascular health, particularly for people living in houses [[20]Feng X. Navakatikyan M. Toms R. Astell-Burt T. Leafier communities, healthier hearts: an Australian cohort study of 105,078 adults tracking cardiovascular events and mortality across 10 years of health linked data.Heart Lung Circ. 2023; 32: 105-113Abstract Full Text Full Text PDF Scopus (3) Google Scholar]. Study participants numbered about 87,000 living in houses and 18,000 living in apartments derived from the 45 and Up Study (Sax Institute) baseline survey [[21]Banks E. Redman S. Jorm L. Armstrong B. Bauman A. et al.45 and Up Study CollaboratorsCohort profile: the 45 and up study.Int J Epidmiol. 2008; 37: 941-947Crossref PubMed Scopus (556) Google Scholar], with 10 years of linked hospitalisation and death data. Astell-Burt and colleagues also report that Australians are ready to receive “nature prescriptions”—that is, prescribing time in nature—as an adjunct to standard care [[22]Astell-Burt T. Hipp A. Gatersleben B. Adlakha D. Marselle M. Olcoń K. et al.Need and interest in nature prescriptions to protect cardiovascular and mental health: a nationally representative study with insights for future randomised trials.Heart Lung Circ. 2023; 32: 114-123Abstract Full Text Full Text PDF Scopus (4) Google Scholar]. As a preliminary exercise to assist in developing future trials, they surveyed levels of need and interest in nature prescriptions in adults with cardiovascular diseases, psychological distress, and concomitants, such as obesity, loneliness and burn-out. Most participants were interested in a nature prescription—a pro-environmental, pro-social, low-cost, and highly scalable intervention. We hope our readers will be inspired to join the Special Issue: Environment, Climate and Cardiovascular Health authors in seeking to understand the causes and effects of environmental and climate change on our cardiovascular health and to learn how to better respond to, and, preferably, prevent the adverse impact of environmental factors on health outcomes. As our invited editorialists Ferguson and Davidson affirm, meeting the challenges ahead successfully will need a whole-of-planet effort [[23]Ferguson C. Davidson P. Moving from rhetoric to action: making a difference for the planet [editorial].Heart Lung Circ. 2023; 32: 4-7Abstract Full Text Full Text PDF Scopus (1) Google Scholar].