Latest / Medicine Matters: The Springer Medicine Podcast / Episode 26: Air pollution and CVD

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Episode 26: Air pollution and CVD · Medicine Matters: The Springer Medicine Podcast

• 0:04
  This
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  is Medicine Matters, the Springer Medicine Podcast.
• 0:14
  I'm Jas Healy, the cardiology and infectious disease content manager for Springer medicine.
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  When thinking about cardiovascular risk factors environmental pollutants such as light noise or plastic are probably not the first thing to come to mind.
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  However one in five cardiovascular related deaths worldwide attributed to environmental exposures.
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  Air pollution is perhaps most prominent example with the World Health Organization reporting that a staggering ninety-nine percent of global population breathe air that exceed recommended limits.
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  This episode we will be taking look at the impact on cardiovascular disease and what can be done to reduce risk.
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  Joining me is Dr Anusha Sanivaratna, an immunologist specialising in Cardiovascular Disease from Royal Holloway University London and founder of Giratwa, International Planetary Health Education Project for Youth in Global South Countries.
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  Thank you for joining me today.
• 1:10
  Thank You Jess and it's a pleasure to be here.
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  To start us off, what sort of impact does air pollution have on cardiovascular disease?
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  So I mean Air Pollution has been known as the threat to cardiovascular disease in many decades.
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  A lot of their studies so far are focused upon epidemiological associations between high levels of air pollution and cardiovascular conditions things like coronary artery disease heart failure, cardiac arrhythmias as well.
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  So most of the studies so far have shown a positive association between higher levels of air pollution and cardiovascular disease.
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  it's only really in recent years we're starting to see more studies that are trying to understand the mechanisms behind this because its not so well understood at the moment.
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  A lot of these studies focus on particulate pollutions thats solid and liquid particles that are present floating partly because it's easier to study, but also because a lot of their epidemiology studies have shown a more consistent link between particulates and cardiovascular disease.
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  But there is also some links in terms of how the gases in that atmosphere things like nitrogen dioxide, sulfur dioxide etc.
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  can affect cardiovascular risk as well.
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  so there's a big association cardiovascular disease.
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  but we're still really trying to understand the mechanisms behind
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  it.
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  I imagine due to the number of known air pollutants that the scope for potential mechanisms is quite broad, you mentioned that particulate matter has been a focus on most studies.
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  what do
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  For instance, particles like diesel exhaust particles?
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  they have a certain coating of chemicals on the outside.
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  Of these particles that can cause chemical changes within our body.
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  so The biggest link is with oxidative stress.
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  So it seems like the chemicals and diesel particle seems to increase Oxidative stress when particles can enter our bodies.
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  I should also mention That thinking behind how particulate matter Can affect health in general is that the smaller particles are, the deeper they can penetrate into their body.
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  So smallest particles will leave to be able to penetrate in the bloodstream and they'll be able.
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  In terms of how oxidative stress happens, it's most likely those chemical changes are causing the release of these oxygen-free radicals and then potentially that may be leading to oxidation of lipids that are circulating in our bloodstream.
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  And... Of course we know that the accumulation of these lipids can start the process of atherosclerosis which is formation of these fat rich inflammatory plaques.
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  at least one example of how these particulates can increase disease.
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  What have gaseous pollutants, what do we know about their interactions?
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  At the moment in terms of the gaseose elements there is some links to increased inflammation particularly around the gases like nitrogen dioxide and sulphur dioxide.
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  again there seems to be a link with oxidative stress which could also then lead.
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  But again as I said it's not well studied areas, particulate pollution.
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  so a lot more work needs to be done in that
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  area.
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  So pollutants are seldom encountered individually.
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  they're often experienced in tandem with other sources.
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  for instance particularly matter from traffic could be associated with the noise and light exposure of vehicles or vehicle fumes being composed by different pollutants.
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  does this sort of interplay complicate research into identifying risky pollutants?
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  Yeah, that's a really good question actually because we're all exposed to so many different things.
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  So many lifestyle factors as well.
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  the way We live our lives You know can cause a lot of stress.
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  you know Things like Like he mentioned earlier things like noise light pollution.
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  these can All affect our sleep circadian cycles for instance and that can have an impact on Stress in there for effect are levels of cardiovascular disease.
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  And but also as you say?
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  You know pollution were not exposed too one particular particulate, we're exposed to so many different things and that of course does make it challenging to understand what exactly is causing health issues.
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  So because a lot of studies do tend to focus on one pollutant at the time trying to tease out which ones exactly are proving most dangerous in terms of our disease risk as I said diesel particles or one of those examples has been shown.
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  you may be aware of more recent studies looking at microplastics.
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  There was a study two years ago now that showed microplastic actually logged inside the arterial plaques with patients who had those plaques removed and in the presence there's micro particles, microplastics correlated to an increased risk-of-stroke as well.
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  so we have some ideas which particles are most dangerous but again until studied each one individually and then perhaps looked at combining some of them, most likely using animal models.
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  And so it's only then we can really understand which ones are the most dangerous.
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  Certainly as a topic that is gaining recognition but more work needs to be done.
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  you mentioned earlier the epidemiological evidence of the association between air pollution and cardiovascular disease.
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  could you elaborate a bit more on what we have seen?
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  So far?
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  because a lot of different studies have been done around In the UK, in London just different urban environments but also around Europe and Asia other highly polluted areas.
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  And then of course there have been links as I mentioned earlier to coronary artery disease cardiac arrest heart failures peripheral artery diseases.
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  well so that's normally affects their legs.
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  of course, there's ischemia in the legs and cardiac arrhythmias as well have all been linked to air pollution.
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  And of course we do tend to see more air pollution in urban environments.
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  so you know we're more likely to see these health effects in the cities.
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  um and also seeing as you know more developed countries start to improve their air quality because low-and middle income countries are also developing that means they're starting to use more combustion vehicles then not obviously making to some zero or low emission transport and energy users quickly.
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  So that means the pollution impacts are starting to shift more towards the global south, particularly areas for instance like South Asia or Eastern Europe also depending on the geographical context as well.
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  Some areas, for instance you have accumulations of air pollution where they're surrounded by mountains or hills and then obviously that air pollution gets sort of trapped in the valleys and those sorts of locations also see higher levels of pollution again with things like worse health effects as a result.
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  so that gives an indication
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  what's happening epidemiologically.
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  The types exposure is something if it quite substantially depends on socio-economic factors.
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  high income countries may seem more vehicular traffic in their cities, whereas lower middle income countries or
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  rural areas
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  would not.
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  There are some societies that might be reliant on the burning of physical fuel in our homes for things such as warmth and cooking.
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  do cases differ depending on the type of exposure?
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  Yeah That's a really good question.
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  So there is yes you highlight they're differences in lifestyle.
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  so an urban environment who'd see more use of fossil fuel combustion, combustion vehicles And so I'm causing pollution.
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  but For example, rural areas like you say it's not necessarily those sort of urban sources pollution.
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  It is quite different.
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  as you see cooking fuels things like wood smoke becomes a problem sometimes in these homes they're not well ventilated.
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  so when there are cooking and burning various fuels some countries still use coal for instance for their cooking.
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  Some places that used firewood.
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  So if they aren't well-ventilated again They will be exposed to the particles released from the smoke.
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  Again, I think there needs to be more studies in these areas that things like cardiovascular disease haven't been well studied In relation to these pollutants.
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  but one recent study That could perhaps give an indication of the impact on health is.
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  There was a study on Californian firefighters who are fighting The wildfires out there and obviously being exposed to the wood smoke particles And in general they seem to be an increase in inflammation markers in their blood cells.
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  genes related to allergies were also upregulated.
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  so it'd be interesting once we study this further what impact is having on cardiovascular disease rates as well because again, its quite an understudied
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  area.
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  Touching your point regarding wildfires at the number of extreme weather events
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  around the world are
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  on a rise due to climate change.
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  do events like
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  dust
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  storms have impacts on cardiovascular
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  health?
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  Yeah I mean definitely For sure.
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  as I said, wildfires do have a similar impact.
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  Dust storms again.
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  they're probably not so much research in that area but thats something thats definitely worth looking into.
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  But also it's worth considering the impact of climate change itself.
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  and course we are seeing greater frequency.
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  extreme weather events And things like extreme heat can increase the impact on pollution because normally when you have hot or climates especially urban environments The pollutants that are already in the air, they're more likely to oxidise due to their extreme heat.
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  So you get a generation of more of these oxidative free radicals which we could potentially inhale and then off course the whole cascade of oxidative stress and other downstream events that lead to disease can happen as well.
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  so obviously climate change is a big concern in relation how air pollution will impact our health in future.
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  aswell
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  Moving on into interventions what could be done?
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  in terms of policy, as well on the clinical and individual levels.
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  So I mean one thing obviously is we need to reduce our reliance on forms of combustion.
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  so things like fossil fuels, combustion vehicles... And As i mentioned We've seen a big risk In relation to diesel exhaust particles.
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  The sooner we can phase out diesel vehicles the better.
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  Obviously we've seen things like low emissions zones, ultra-low emission zones in various cities around the UK and they have already had a massive impact on improving air quality.
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  So it's really important to keep up that momentum.
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  I think ultimately the main solution is essentially restructuring our transport infrastructure so public transport can be more accessible for everyone internationally as well, and also encourage more active forms of travel.
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  So things like improve our cities so that people can walk and cycle more easily which obviously will have health benefits in itself.
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  And we really do need to reduce our reliance on cars.
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  even though We are moving More towards electric cars and that is an important solution In terms of reducing the amounts of pollution On roads then it's already been shown to have a positive effect in That way.
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  Obviously there are other pollutants sort of linked electric cars that are increasing concern to things like brake abrasion.
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  dust could be an issue as we see more electric vehicles on the road because they're heavier so it causes friction in the tyres and generating tyre abrasion at dust.
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  So, electric vehicles aren't going to be a solution for everything.
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  We really need to improve our public transport infrastructure.
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  As I said Promoting and encouraging more active forms of travel as well is going to really be beneficial in terms tackling air pollution but also climate change, population health too.
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  And then these things are not gonna happen overnight.
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  this it's gonna take a long time to make those changes.
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  so we do need think about short term mitigation.
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  measures to protect public households could be things like advising people on how they can protect themselves when their going outside perhaps go outside when we know air pollution levels are lower, perhaps avoiding rush hour traffic times for instance using air purifiers at home.
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  Perhaps face masks if they know that they're going into a highly polluted area.
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  sometimes indoor pollution is also a concern as well.
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  so things like indoor dust particles that regenerate from our own cooking can be the concerns of opening windows making sure homes are well ventilated vacuuming carpets often and reduce the generation of that indoor dust as well.
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  And just generally, following a healthy lifestyle has with anything you know...a healthy diet good levels of exercise sleep and so on is always going to be beneficial in terms of helping protect our own health from all these different pollutants.
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  I should also mention we need make sure everyone have access green spaces because thats really beneficial for health.
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  trees plants themselves are very good at Absorbing air pollutants of.
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  that will also be really helpful in terms of cleaning up our air quality as well.
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  Air pollution and climate change are, of course quite heated topics when it comes to policy implementation.
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  how do you think these changes
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  could be approached?
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  Yeah!
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  That's a really good question because obviously we've seen in recent years public opposition quite high-profile case in London with the EULES scheme coming in.
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  There seemed to be a lot of misinformation around implementation, people who thought they would have to buy new vehicles when actually it had been perfectly fine under the EulaEscheme.
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  so obviously that indicates we really need make sure there's clear messaging on these policy measures and minimise or completely cut out misinformation as much as possible which is tough within social media.
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  We need to make sure that everyone has access to the right information, education is really key priority when it comes to implementing these policy measures.
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  That's often one of the most important factors ensuring that everybody is aware about all those details in relation to this.
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  Finally there are quite a lot more research needs done on the area.
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  In terms of future direction do you think we should be focusing on understanding the impact of individual pollutants or should we perhaps start to look more at intervention and misogation strategies?
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  Yeah, I think it's a combination of those things that need to focus.
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  So as you say... We really need to establish which pollutants are most dangerous so that we can prioritise what to target our transport public health policy in terms For instance, focusing on different types of particles coming from vehicles and so in.
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  And understanding how severe the health effects are for those different type of particles.
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  But there also many different air pollutants that are emerging as well as a chemical pollutant's for instance That are emerging.
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  There is much out there we probably still don't really know about.
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  We even no exist.
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  So obviously need to understand what were being exposed too.
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  Obviously there is increasing research looking into microplastics because that's a massive concern now, so much of the environment has contaminated with it.
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  There are also forever chemicals often these plastics.
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  they're treated with and could leach in to their environments Things like furniture.
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  I've been treating them as flame retardants for example.
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  So again we see all sorts different pollutants and chemicals being exposed.
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  We really need to understand risk And as I said with electric vehicles there's a concern around brake abrasion, dust and tyre abrasion.
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  Dust is well so you want to understand once while we're transitioning into this zero emission society what sort of impact that it will have on health?
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  It also really important for us to understand the biological mechanisms because like I've said many studies have focused on epidemiological links.
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  You don't fully understand the biologic mechanism.
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  For instance precise inflammatory pathways are being activated in response to pollution.
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  I think once we can understand that it will help us establish what the most appropriate mitigation measures are, in order to protect public health and particularly for those more vulnerable patients who perhaps these sort of mitigation measures not enough?
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  We also need to think about what clinical interventions would be beneficial.
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  Perhaps they're already taking that could provide some benefits or other potential therapies, markers of disease we can use as an indication to help protect them in the future.
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  That's brilliant!
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  Thank you so much for your time Dr Senefaratna.
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  My pleasure.
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  thank you very much for this invitation as
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  well.
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