[MUSIC PLAYING] We are the Association for Child and Adolescent Mental Health, or ACAMH for short. And this is ACAMH Learn. Hello. And welcome to Mind The Kids Podcast series. I'm Mark Tebbs, and I'm your host for today. I've kind of spent my whole career working in mental health in different aspects, from frontline service delivery through to being director of commissioning. At the moment, I'm currently a chief executive of charity. So we're working with grassroots organisations and really focused on community impact. My commissioning background makes me really interested in understanding need, lived experience, and evidence-based practise. But I'm also a parent who's experienced a system from a parental perspective. So I'm delighted to be hosting this podcast. We get the opportunity to speak to researchers and practitioners, trying to rely on the latest research and to hopefully inspire you with some of those latest developments. Today I'm delighted to be speaking to Dr. Silvia Alemany, who's the lead author of a ACAMH paper called associations between air pollution and surrounding greenness with internalising and externalising behaviours amongst school children. So I'm really delighted to be joined by Silvia. Silvia, welcome to the podcast. Thank you very much, Mark. I'm also very happy, and I'm grateful for your interest in our work. Yeah, it's a super interesting paper. Do you want to just start by introducing yourself and maybe saying a little bit about your research interests and where you work? Yeah. I'm Silvia Alemany. I'm a principal investigator in the research group of psychiatry, mental health and addictions from the Institute of Research of [INAUDIBLE] in Barcelona, Spain. And I'm in this team. This team is led by Marta Revis Antonio Ramos Quiroga. And the word you are interested in is actually lead for the first author who is [INAUDIBLE] one of the PhD researchers in our group. Great stuff. Excellent. So let's dive in. It'd be really helpful just to set the scene for the listeners. So if you could just say a little bit about the overview of the study that we're talking about today. Yeah. So I think that the main findings for our study was that in this population of 4,500 individuals, actually children and adolescents from the general population of Catalonia, we observed that air pollution was related to more behavioural and emotional problems related to internalising symptoms, while greenness was related to lower levels of externalising symptoms that maybe later we can define, which means internalising and externalising symptoms. But I believe this is the main findings. And one of the things that makes this study different from others, because this is an emerging area of research, and actually we are not saying anything really new, but more research has been done on adult mental health. And I think there's relatively scarce research on this type of physical environmental factors in child and adolescent mental health, especially the level of symptoms and the level of general population. So not only in diagnosis. There's more research on ADHD, or autism, or spectrum autism. But relatively, there is less research on more dimensional approach to these symptoms. Regarding our particular setting, it's also-- there's quite some papers studying similar objectives to ours in the city of Barcelona. But this is the first study covering the whole area of Catalonia. So one of the regions of Spain. So I think this is the first one covering this area. And I think this is also important because it's out of only one city centre. So it's also covering other regions, more rural regions from our territory. Yeah. So I was looking at some of the research in London, and we've got an ultra low emission zone across London, which has really impacted and improved the quality of the air. And the research seems to focus on older adults and respiratory problems. What was the inspiration behind you wanting to look at the issue of pollution, child development, and greenness? Well, actually, it's totally true what you are saying. So I did a postdoc in the Barcelona Institute for Global Health. That was my first contact with the topic of air pollution and the harmful effects on health. So I learned the history from air pollution. Its first linking that to respiratory issues. Then more recently, related to cardiovascular issues. And in the last two decades, more related to also neurodevelopmental and neurodegenerative disorders. So the more recent organ, let's say, that has been linked to these harmful effects from air pollution, it's the brain. And most of the research has focused, I think, so far more on dementia and neurodegenerative effects. And there are very interesting results from Dr. Calderon Garcia Duenas. She did a very pioneering research on that, finding some hallmarks from Alzheimer disease on the brain, postmortem brain tissue of dogs, and then of postmortem tissue of children. So it was very shocking for science to see hallmarks of a disease is typically seen in older populations already in children. So that inspired a lot of research on air pollution on brain. But most of the research has focused on adult mental health and adult, as I was saying, dementia. And probably in the last-- I would say in the last decade or even five years, there are more research on child and adolescent mental health going beyond this ADHD and autism. I think we are in a moment that we are finding typically some kind of studies with inconsistent results or negative findings. So I think it's a moment that we really need to increase the research on this topic to see how the evidences converge. And it is also typical from environmental epidemiology. Well, I also work with genetics. But especially environmental epidemiology, we use different types of measures to capture and to estimate these environmental factors and also to assess mental health. So sometimes it's difficult to compare the studies and to see whether evidences are converging. So I think it's extremely relevant to continue doing this research. So this is what's in our agenda since we have this nice sample and we have the schools and we could geocode the schools and see what was an estimate, the exposure to air pollution, and greenness at the level of the schools. Yeah. OK. So tell us a little bit more about that. So how did you go about conducting the study? I'm particularly interested in how you measured air pollution, how you measured greenness. If you could tell us a little bit how you went about that, then that'd be great. Yeah, sure. I'm not an expert on this. So this is what something we did in collaboration with IS Global with the Barcelona Institute for Global health. They are experts. We have Antonio Valentin. We have Mirella Gascón. We have Jordi Sunyer in our paper. And we have Maria Foresti. And we needed these researchers to geocode the schools and then to estimate. So I mean estimate. And I think it's important because we are not measuring the exposure. We don't have filters at the school that we can then analyse, like doing some kind of chemical analysis. What we have is maps that have been modelled. And there are different models. So we collaborate with these experts to try to choose which is the best model that we can use for our goal, for the goal of our study, and for the characteristics of our study. So basically, we have a map of Catalonia where you can put your geocoding sites, where you want to estimate these different air pollutants, or greenness, or other measures. And what they do is when we give them a date, they can give us an average, an annual average for certain times, in our case, before the behavioural assessment. So we were able to study what-- we have an average of the 12 months before the behavioural assessment of the certain levels of different air pollutants and also greenness around different buffers, around [INAUDIBLE] metres around the school, 500 around the school. So these are estimations. So this may limit in some way the study. But we are using validated models. So they are based on mathematics. They are based on satellite images. And they are developed by experts on this. And this is also nice because we are seeing that our results align with results that use another methodology, which is actually based on directly measuring at the schools the air and greenness. So I think we can really rely on these estimations. So I think it's a bit difficult to understand this for the general population. But this is how we estimate the exposures. I think you explained it really well actually. So I was curious. So it's something I've not really thought about before. But is the kind of air quality very localised? So within close kind of neighbourhoods you get quite big variations in air quality. At the level of our study-- and I have been asked about this before. Because of confidentiality issues, because we don't want to alarm people, we were not doing anything related to localise any centre or a particular school where levels were particularly high. I'm also aware that at least in Catalonia, the government is studying this and is in contact also with scientists who study this. So they also monitor this. So in our study, it was not our research question to make a difference between highly exposed, let's say, or schools comparing schools with higher levels to schools with lower levels. So we're just working with the individual levels. And also because we were linking the exposure of the kid to the time where behaviour was assessed. So we were not comparing either rural versus urban or taking into account what I was saying, no more schools with a particularly high exposure. But definitely, this is something that I know authorities know and take into account and also consult experts about this. And there might be differences. Also here, it's important to say that we assess a kind or a set of air pollutants. We try to be very comprehensive. So we use a particulate matter and nitrogen dioxide, like the typical ones. But we focus on five types. So other studies only focus on one. We believe it was important to have a kind of comprehensive different types of pollutants that are decreasing the quality of the air. But when we face the fact that we are studying Catalonia, we don't really know the sources of these different pollutants. So in the case of Barcelona city, previous research has indicated that traffic is the main source for these air pollutants. But in other regions, we are not sure about what is the source. So it is not our main goal now or the main goal of this study to focus on these schools that may be at particularly high risk. But definitely, this is something important. And I know authorities are aware of that. Yeah. There's quite a lot of local campaigns just to try to get drivers to turn off their engines when they're waiting outside schools, for example. So I think that there is definitely more increased awareness and trying to be a little bit proactive around particularly the kind of traffic impacts here in the UK for sure. And then just greenness as well. When I first read the paper, I was expecting greenness almost to be like shorthand for outdoor space. But it is actually the measure of greenness, as in UV light. So could you just talk a little bit about that. Yeah. So I mean, the measure we use for greenness is this normalised vegetation index. So it's a very typical measure. It also can be a bit broad measure. But also this was our first paper on this line that we aim to continue. So we wanted to pick up an index that was widely used in the literature. We also wanted to see how our results, how our setting was working, whether we were finding something that's in line with the rest of the research. So what we are actually measuring is the amount of leaf vegetation. So green vegetation. And this is something done with satellite images. And then we have all the details in the paper. And again, we have these experts who-- because my main research line is genetic and environmental factors, so I really need to rely on people who is expert on this. And what we learn is that this index is related to the amount of green vegetation. The actual factor that we see that is associated with lower levels of externalising problems is the vegetation 100 metres around the school. So that means more or less probably the vegetation that children and adolescents can see from their windows. So somehow, this vegetation, it's either cleaning the air or it's either having some kind of relaxing effect on them. We don't know this. I'm just speculating based on previous theories. But this is what we observed. We observed a similar pattern for the vegetation at 300 metres and then at 500 metres. The significant association was at 100 metres. So this is just what they will probably see from the window. So probably even within the school, it was this green vegetation that seems to have some effect on their behaviour. So this is what we were measuring actually in this paper. But there are other measures. And we plan to explore other measures for greenness. Right. Before we get into the results, I just want to unpack a little bit about the measurements of internalising and externalising behaviours. So just how did you define and assess those in the paper? Yeah, yeah. We use the CBCL, which is from the Aseba. I'm not sure if I'm pronouncing this correctly, but it's a set of different instruments that parents, teachers, and adolescents can feel. So it's a self-reported instrument for adolescents. But in our case, we use the parent-reported instrument. So parent report on their children behaviour during the six months before. And it's a widely used instrument. And this instrument allows us to have different categories of emotional and behavioural problems. And in our case, we choose to use two broad band scales, which it is called. And it's because in a childhood psychopathology in the field, you can work with these two broad categories of internalising and externalising. So internalising symptoms refer to those symptoms that are like a psychological distress that is directed to the person, towards the person, to yourself, like depression or anxiety, so something like you internalise this emotional distress. While externalising symptoms refer to those symptoms or behaviour that reflects some psychological distress that you direct outwards. So to your environment, to other people. So internalising symptoms will include things like anxiety, or depression. In the case of children, also somatic complaints like my stomach hurts, I have headache, or things like that. And in the case of externalising symptoms, this includes more disruptive behaviour like aggressive behaviour. Or in the particular case of this instrument, it's also delinquent behaviour like lies or stealing things, this kind of behaviour. So this is kind of understood as emotional problems like are directed to the environment, to others. So we decided to use these two broad categories. OK. So what did you find? What was the association between greenness, air pollution, and internalising and externalising behaviours? Yeah. So we found that air pollution saw two of the air pollutants that we were assessing. Those with diameter of 10 micrograms and another one which includes 2.5 to 10 micrograms, so actually there are not the very, very small particles, were associated to more internalising problems. While we found that greenness at the level of 100 metres that I was mentioning before, like more or less what they can see from the windows, was related to less externalising symptoms. So that was our associations. OK. So one was like a protective factor and one was like a harmful factor? Yeah. OK. Exactly. So was there an interaction between the two environmental factors? Yeah. Actually, we don't analyse this. It's a very interesting point. And this is something we plan to do in our study. We didn't examine that, but it's one of the theories, is that greenness may act through cleaning the air. So that may be one indirect effect of greenness. But there are other theories indicating that greenness can have a direct effect on behaviour, such as air pollution. It's very likely that we know from many evidences that air pollution has harmful effects on all the organs of the body. And greenness or greenness, we have different theories. For instance, greenness may have some kind of direct effect. They talk about restorative effects like relaxing the body and the men and relaxing, reducing the stress. But also through other factors. So more green spaces may also promote physical exercise or promote social interaction. And we believe that this is particularly interesting for our findings because we only find this association of greenness with aggressive behaviour, with externalising behaviour. So maybe this association might be mediated by these factors, by more physical exercise. Or more interaction with other people may help some kids or some adolescents to regulate their emotions that are more aggressive. But this is something I'm just speculating. This is something that we will try to further investigate in the future. OK. I'd like to turn to a little bit about the limitations of the research. So what do these findings suggest in relation to urban planning? So I'm just thinking about what schools can do to mitigate or enhance the well-being of their children and young people. Yes, totally. I think this is a very important aspect. And all the research in this line have these implications for policymakers and for public strategies to promote and prevent mental health. So we know that-- I think it's very important to reduce the traffic around the schools and also take care of the paths or take care of those roads to the school to try to facilitate or to try to provide citizens and families with certain ways to get to the school, avoiding very busy roads and more greenness or more other roads that can be ideally with more green spaces. Also at the level of the schools, I think there can be changes in the playgrounds because also we have quite a lot of research also related to the sand and some of the materials that there is in the playgrounds. But I believe greenness is very important. And also as we are talking now during the summer and we are experiencing these heat waves and everything, for climate change, I think it's also very important. So our findings in a way are relevant for child and mental health. But I think they are globally important for climate change and for planet. We told more and more about planetary health and one health. So if the planet is not healthy, it is very difficult that humans are healthy. So all these strategies actually will have an improvement also potentially on climate change and all of us and also on the temperatures. I think this will be one of the biggest topics in the next years probably and also for mental health. So yes, I think policymakers and authorities are well aware of this. Probably not doing enough, but there's a lot of strategies to mitigate these effects and to provide citizens-- I think it's very important to provide citizens with economic and with quality public transport networks and to provide spaces to leave the car and have a easy way to get to the centre of the city. But I cannot avoid to say, as a scientist, as a citizen, that it's very important that authorities promote global changes. So they think globally, because I think it will be very, very bad if any of these strategies increases socioeconomic inequalities. So it is very important, I think, to take into account that not everyone can afford paying a parking, or arriving at certain times, or certain things. So I think it's very, very important that they think in a global way about really have cities, especially with economic and really good public transport network and easy way to get there, not only for the people within the city, but also from the people outside the city. Yeah. I think it's really important that we're joining up that green agenda with being and a kind of physical and mental being of the whole population. I guess what I kind of quite liked about the study was because the impacts of the greenness was kind of very local, it felt like there were opportunities to empower our schools and young people to change their physical environment hopefully, whilst the national, kind of global picture is addressed by our politicians and leaders. Exactly. So I'm just wondering about messages to parents who are concerned about this issue. Is there anything that the paper suggests that would be good advice for parents? Well, I believe for parents and family and school staff, it's very important to take into account that the effects that we are seeing are a small effect. So hopefully, the effects, at least on mental health, are a small effect. So the important message is also to understand the mental health problems are multifactorial. All the evidence so far points toward different factors taking into account in order to finally observe a kid or adolescents with a diagnosis or with severe or important mental health issues. And probably behind this or underlying these problems, there are different kind of factors. So I think it's very, very unlikely that these physical environmental factors can totally explain complex disorders like ADHD, like autism spectrum disorders. So this is to try to temper our message and to not concern our families and parents that the effects are small. But the importance of this effect is because the exposure is global. So it's a large proportion of the population exposed. So even if we make a very small or marginal change in these exposures, we may a little bit decrease the risk for future mental problems or even in adulthood, while we are protecting the planet and protecting other aspects of the health. And also for parents and families, of course, there are individual measures that they can do. And if they are particularly concerned about, for instance, the location of the school of their children, there are associations. They can go to the authorities. There is more and more citizen science, a way to engage citizens with scientists so we can together work to find a way for some particular cases or any concerns that citizens have. And also, as I was saying, it's just important to try to avoid very busy roads with a lot of traffic. And we know that just putting a little bit of distance between the sources of these air pollutants like vehicles decreases a lot the exposure. So just to try to be a little bit far from these roads and as much as you can try to expose the children to natural environments and to be in contact with greenness and also with rivers and with blue environments, we believe it's, in general, a good advice for mental health. Yeah. That's really helpful. I think that gives a real balanced perspective on the work and the area. So just thinking about future research, is there any future research you're planning in the area? Yeah. Actually for us, this is like our first paper from our group and in this sample. So we plan to continue investigating these effects. And we have now-- we have more participants. We are lucky that we have more participants. So we will be able to have more power. And we are very interested in seeing any potential moderating effects. As I was saying, if we are capable of trying to investigate any mediated effects by physical exercise or moderating effects from a genetic susceptibility, we are a group-- we are more experts on genetic factors. So to me, it will be really, really nice if we can see if there is any individuals that can be more vulnerable to these factors because that will give us some clues about the mechanisms involved from these associations, which is, I think, something that it is still unclear how these physical environments can get into the body, can finally affect the brain, and we can see these associations. And also, as I was saying, we are also very interested in the role of socioeconomic status. So we will continue trying to see whether these effects are different or act as a function of sex, of age group, and also of socioeconomic status. This is something that we will continue investigating. And also other outcomes, we plan to investigate these effects on school performance. For instance, we believe this is very important. And we may investigate also some diagnosis because we also have screening and we have very nice data for this sample. So we may also try to see other mental health outcomes more clinically relevant, let's say. Yeah. OK. We're coming to the end of the podcast. So I'm just wondering whether there's a final take home message or if there's anything you want to say that we haven't had the opportunity to speak about so far. I think I can summarise the main finding. Like air pollution seems to be or we are contributing to the line of research like suggesting that air pollution can be a risk factor for mental health during childhood and adolescence. While greenness may be a protective factor, which we believe is very important because these are factors that can be modified. So we can actually intervene or authorities can help to intervene on these factors. And as I was saying, I would like to highlight that the effects are small. They matter because the exposure is global. But these are multifactorial outcomes. So there are other factors really important. But because of their impact in global health, we will continue investigating the role of these physical environmental factors on mental health. Great. Thank you, Silvia, for such an interesting conversation and good luck with your future work in this really important area. So thank you very much. Thank you very much for inviting me to this podcast. So if you've enjoyed the podcast, then please give us a rating or review on your favourite platform. Thank you very much. [MUSIC PLAYING]