What is public health?

Today we're going to explore the question, what is public health? I get asked this question about once a week, what is public health? What do you mean by public health? Now if you look up a definition of public health, if you look it up online or look it up in a dictionary, you're going to get something that's verbose, it's going to be wordy, it's going to be flowery. What I'm going to do is a little different. I'm going to say look, let's have a very simple definition of public health and then as a separate question, let's ask what do public health professionals do? So really what we're going to have is a simple definition and then some complementary jibber So here's my definition of public health. Public health is a discipline that addresses health at a population level. No more, no less. That's the definition. Now we can add on some complementary jibber jabber to try and understand that a little better. So for example, we might want to talk about the fact that public health is different from clinical medicine and other paramedical disciplines like physiotherapy and occupational therapy, which deal with patients at an individual level. Public health really looks at groups of people and those groups include sick and well people and those groups are delineated at any level that you want. It could be a community, it could be a country and of course it could be global health. Now let's take a closer look at the second question. What do public health professionals do? Well public health professionals try to do two things really. The first is to understand and the second is to act. Now let's look at each of these components separately and then we'll look at how they work together. When I say that public health works to understand, I really mean that we gather information and evidence that will inform how it is that we intervene and act. To understand population health, we do two things really. We do surveillance and we do research. We're trying to learn more about what we call exposure. So exposure could be risk factors, what could be interventions and we're trying to understand outcomes, disability and disease. And with respect to all of these factors, we want to understand their distribution and their magnitude. So magnitude is kind of self-explanatory. It's how big, how much and with respect to distribution, we mean distribution geographically, so physically where are these exposures and outcomes and of course we mean distribution sociologically across for example different socioeconomic groups or cultures etc. So we're doing the surveillance and this research to understand the distribution and the magnitude of exposures and outcomes so that we can do two things. Firstly we want to understand the causal relationship between exposures and outcomes and secondly we want to plan interventions to improve public health. And of course these two things are connected. So the better we understand the causal relationship between exposures and outcomes, the better we can plan interventions that we know will work and will have an impact on public health. So we've talked about the first area where public health professionals work and we've shown how this all leads to a point where we've got a better understanding of how it is that we can intervene and plan programs that have an impact on public health. And so this of course leads us to the second area that public health professionals work which is to act. In other words we want to act on that understanding. Right so we intervene really in two ways. We want to keep healthy people as healthy as possible and we want to ensure that people that are unwell have access to care and treatment. So let's look at the first one first. What do we do to prevent disease and disability? Well we do two things. Firstly we promote behavior change and secondly we reduce exposure to risk. And of course as you can imagine there's a lot of overlap between those two. So with respect to promoting behavior change there's really two things that we try to do. We want to promote behavior firstly that we know will have a positive impact on health like improved diet, exercise etc. And of course we want to deter behavior that we know will have a deleterious effect on public health like smoking. Then with respect to actions that we take to reduce exposure to risk we do this by addressing two kinds of risk. Firstly there's the physical and environmental risk factors that people are exposed to. Things like radiation, water contaminants, unsafe medicines. And secondly there's what we call the social determinants of health. Things like human rights violation, gender discrimination etc. So now we've talked about what we do to prevent disease and disability in otherwise healthy people. Now let's talk about what we need to do to ensure that care and treatment is available for people who are unwell. So as you can imagine I'm going to tell you that there's two things that we do. The first thing that we're going to do is we're going to use best evidence. So we're going to lean on that understanding that I referred to in the first half of this talk. And we're going to use that to advocate for policy change that ensures equitable access to safe and effective treatment. In other words we want to make sure that all people have access to health services. And the second thing we need to do, and of course it's related to the first, is that we need to ensure that the health systems are in place to provide care and treatment for people that need it. Now health systems can be thought of as two things. The first is capability and the second is capacity. Capability is what you're able to do, what you're capable of doing. And this is really a function of things like health service planning, governance, leadership, information management, etc. And then there's the other side of health systems. It's what we call capacity. How much you're able to do. And this tends to be a function of finance, products, and human resources. In other words, the more money, the more products, and the more people you throw into the health system, the more capacity the health system has. In other words, more people will get treated. So that's really public health in a nutshell. Like I said at the beginning, the definition of public health is that it's a discipline that addresses health at a population level. What it is that public health professionals do, well that's a slightly longer conversation. What I've talked about here is certainly not comprehensive. I mean there's more to public health than what I've mentioned. But this is perhaps a good schematic that you can use to place the studying or the work that you're doing in the context of a broader set of activities. Thank you for listening. I hope you found this useful.