Thank you very much for this privilege and for being invited to this committee. For the sake of time, since we have 10 minutes, I'll do my presentation in French. It's really a matter of fluency.
I am an interventional cardiologist. I was head of the cardiac catheterization laboratories at the Notre-Dame hospital, at the Centre Hospitalier de l'Université de Montréal, and at the Cité-de-la-Santé. I created 42 research protocols. I am an associate professor of medicine and I've had students. So regarding a university career in interventional cardiology,
I mean, to implant stents to dilate arteries,
that is my life.
Five years ago, I wrote a scientific popularization book called Prévenir l'infarctus ou y survivre. This book led me to read documentation that an interventional cardiologist wouldn't normally read, whether on public health or environmental health.
Obviously, when people have a heart attack, they always ask why it happened to them. That has been the case for a long time. That is what is shown here. Why do we have heart disease or atherosclerotic heart disease? The Framingham study, which began in the United States in 1948 and is still ongoing today, has shown us the following.
The main risk factors are tobacco, heredity, diabetes, high cholesterol, high blood pressure, sedentariness, obesity, and stress. With the recent literature, we may ask, did Framingham say everything about this situation?
There are a few facts that I want to mention. This was the beginning of my research five years ago, and actually I'm planning to establish a chair of environmental cardiology at Montreal University, and it is going forward.
Heart disease is rare in animals. Heart disease was rare in humanity before the industrial era. Just ask the anthropologists: there are many studies about that. Heart disease is rare in humanity living outside the industrialized world.
However, you may induce heart disease in animals and they are, in fact, a very good bench test for all of our devices: pacemakers, medications, heart valves, etc.. You always see a dramatic increase of cardiac morbidity following a traditional industrial revolution.
For the book Planète Coeur, which I brought, I obtained the numbers from Statistics Canada. I know we have to submit documents in both languages, but for those who are interested, I would like to specify that the 500 studies that I will summarize here in 10 minutes are condensed in Planète Coeur. The book was published by Éditions du CHU Sainte-Justine. I brought copies. It is in French, but an agreement was signed to have it published in English and it is currently being translated. I know I'm departing from the rules by not submitting the documents right now in French and in English, but for those who are interested, the French version is available immediately and the English version will be within a year.
From a historical point of view, at the turn of the century in Canada, cardiovascular mortality was low. It was the same in the United States. It peaked in 1950, exactly at the same time as in the United States. Then, what was called an American epidemic happened. During that period, one in three Americans had an acute heart attack at age 50.
That was the main reason Americans carried out the Framingham study: because one American out of three was having a heart attack by the age of 50. Looking at the people here, you see the number it represents. What we see also is a huge difference between many countries.
On this slide from the World Health Organization, we can see the cardiovascular mortality rates in Europe. They vary between 60 and 700 per 100,000 people. Let's take the case of the main countries: Switzerland, Austria, Poland and Russia. In Switzerland and France, the cardiovascular mortality rate is 60 per 100,000 people. In Ukraine or Russia, that rate is multiplied by 10. We are therefore talking about a 1,000% difference in cardiovascular mortality, which is huge in medicine. It is one more indication that allows us to see that it is not just classic risk factors that determine these differences.
On the planet, some groups live outside the industrial world. For example, there are the Tsimanes, who live near the Amazon in Bolivia. Well into old age, they have practically no atherosclerotic heart disease. It appears that cardiology is an environmental specialty. That is what we deduced four or five years ago. Based on the time and place where you live, your risk of having an acute heart attack varies.
It's the same for stroke. It's the same disease. It's a vascular disease. Your risk of having a stroke or a heart attack is totally different according to the place you live.
Let's go straight to the conclusion. If we're talking about a cardio-protective city, what would be the environmental prescriptions of an expert in environmental cardiology?
First, we would need to eradicate food nano-aggressors.
Second, we would need to eradicate airborne nano-aggressors.
Third, we would need to eradicate fossil fuels, reconnect with nature through renewable energies, and achieve a 25% urban canopy, that is to say tree coverage in urban areas.
We therefore need to redefine atherosclerosis, the main cause of heart disease, by three triads: what we are, that is cholesterol, hypertension and diabetes; what we do, that is sedentarity, obesity and tobacco; and where we are, that is environment, food and urbanism. That last triad is important. Yet, it was completely underestimated until 10 or 20 years ago, and I will talk mainly about that.
To properly understand the importance of interaction with the environment, we need to know the following. In one day, I eat 1 kg of food, I drink the equivalent of 2 kg and I breathe in 20,000 litres of air. That means 20 kg of air go through our lungs every day. There is a constant exchange. You know the brain cannot go without oxygen for more than five seconds, otherwise you lose consciousness immediately. It is these exchanges with the environment that have been underestimated until now.
Let's see what we would need for a city to be cardio-protective. I will give you a cardiologist's point of view.
In a city, what is good and what isn't? Food nano-aggressors need to be eradicated, because I think they are part of the environment. In fact, the bread you eat is not the same as the bread eaten in Japan or France. Without getting into food too much, I would say three things are important: trans fats must be avoided at all costs, excess salt must be diminished and regulated, and finally, industrial sugars must be eliminated, i.e. glucose-fructose syrup. If Canadians eliminate excess salt, trans fats and glucose-fructose syrup, their risks decrease a lot. The numbers are significant: we are talking about a 50% lower diabetes risk and cardiometabolic risk. I believe industrial food, as it is served, is part of the environment.
Next, airborne nano-aggressors and fossil fuels need to be eradicated. The history of humanity teaches us many lessons. Think of the Great London Smog in December 1952. It shows us that every time pollution peaks, the mortality rate skyrockets. In three days, the Great London Smog alone caused 12,000 deaths. It was in 1952.
More recently, pollutant rates have continued to be measured and links have been made between them and cardiovascular mortality rates. In fact, when we look at this slide—which was presented in Circulation, one of our bibles—we see that it was enough to have the day's pollution rate to predict the mortality rate. In fact, we are increasingly realizing that they are directly related.
It is due to fossil fuels and fine particles. Every time we burn fuel oil, oil, coal or any fossil fuel, particles are emitted into the air. We breathe those fumes, which have two properties. That is why we call them ultrafine or fine dust: the particulates are so fine that they make their way directly from people's lungs into their arteries. Moreover, they are so toxic that they trigger an enzymatic cascade of inflammation and lead to thrombosis and arrhythmia, and then heart attacks, strokes and sudden deaths.
I will give you a very simple example from one of the studies reviewed. Groups of rats were fed a normal diet and others were fed a high-fat diet. The rats' aortas were sacrificed. The aorta is in blue. The red part in the middle is the atherosclerosis. That is what blocks arteries, which we unblock everyday with our teams using bypass grafts, especially. We see that a rat with a high-fat diet has a larger atherosclerosis section than a rat with a normal diet. No one is surprised. However, there is one interesting thing in these experiments by Valentin Fuster, done at Mount Sinai Hospital in New York. Valentin Fuster is one of the biggest stars in fundamental cardiology. With polluted air, this effect is amplified. Consequently, eating junk food in a polluted downtown area causes major sections of atherosclerosis, which leads to strokes and heart attacks.
Many studies have identified the links. We see that every time there is an increase of 10 micrograms per m3 of particles emitted by fossil fuels, there is a 10% to 25% increase in heart attacks and sudden deaths.
This is a brief summary of the studies on this topic. It has been studied a lot from a mechanistic and physiological perspective. It is now a branch of physiology that could be called ecophysiology, the cardiovascular influence of air pollution on our environment.
We wondered if it was that important compared with other factors. Yes, it is an important cardiovascular factor. In 2008, information was published in Canada revealing that pollution caused 20,000 excess deaths, 5,000 to 11,000 cardiovascular deaths, 33,000 to 67,000 cardiac hospitalizations, 1.5 million hospital days, at a cost of $9.1 billion. These are excess deaths, following pollution peaks. It goes beyond chronic pollution, which is an environment that is always polluted.
Reconnecting with nature, using renewable energy as an alternative and achieving a 25% urban canopy, would that have advantages? In the United States, a very large-scale study that was published in the New England Journal of Medicine demonstrated that for 500,000 Americans followed over 14 years, decreasing the fine particle rate improved life expectancy. There are even neighbourhoods where life expectancy increased by four or five years because pollutants had been reduced. This is a rock-solid study: 500,000 patients were followed.
I will now say a few words about urban heat islands and revegetation.
In Quebec, studies were conducted with the help of the Canadian Space Agency and images from the RADARSAT and Landsat 5 satellites. They documented very high ground temperatures, in this case urban heat islands. I think the most important thing to understand is that not only do urban heat islands appear where there are no trees, but also that the rise in temperature increases the toxicity of pollutants. A study on this subject was conducted in Atlanta and New York.
A great study was published in The Lancet. This British study, which had 40 million subjects, showed the link between living in a green area and cardiovascular health. It can be summarized as follows: if you live in a green area rather than in a mineralized, polluted area, you cut in half the difference in mortality that exists between the rich and the poor.
If a city eliminates food nano-aggressors, i.e. trans fats, excess salt, glucose-fructose and phosphoric acid, as well as airborne nano-aggressors like carbon monoxide, sulfur dioxide, nitrogen dioxide, fine particles, ultrafine particles and volatile organic compounds, and it becomes a green and active environment, with a 20% to 25% canopy, it can expect a 25% to 75% reduction in cardiovascular diseases. Obviously, it won't be the same in Lyon as in Beijing.
Salim Yusuf, one of my eminent colleagues from McMaster University, said that heart disease was rare in 1830, but he wondered if it could become rare once again in 2050. It is a challenge we all face.
Those were, in 10 minutes, my thoughts on the links between the environment and heart health. They are much more significant than I thought at the beginning of my practice. It was a pleasure to talk about them to this committee.