Introduction to Public Health

[MUSIC PLAYING] [MUSIC PLAYING] Welcome to an introduction to public health. My name is Susie McCarthy. As a health education specialist at the CDC, I've worked in a variety of areas of public health, including children's health, infectious diseases, chronic diseases, and most recently public health workforce development.

Public health is a dynamic and multi-disciplinary field as you'll see from this introductory course. This slide shows the outline for the course. We will begin by discussing the purpose of public health and a few key terms.

We will then look at some events in history of public health. Next, we'll go through the public health approach and apply it to a public health problem. We will then cover the main functions and essential services of public health to show the broader context and identify different groups who have a stake in public health.

Lastly, we'll discuss factors that determine health, and I'll present the health impact pyramid as a framework for influencing public health at different levels. This introductory course should enable you to achieve the learning objectives on the slide which align with the course outline that I just covered. So what is public health?

CEA Winslow was a leading figure in the development of the modern study of public health. Read this definition of public health that he developed almost a century ago and consider key words or phrases in the definition that speak to you or tell you what public health is. You might notice that as a combination of science and art, public health offers many opportunities to be creative.

Public health is not only about preventing and treating disease, but it's also about promoting good health. Winslow says this is done through organized efforts. So what are some examples of organized efforts?

You might think about how national surveillance systems are set up, how our waste management infrastructure is built, or how the latest vaccination recommendations are developed and communicated. From Winslow's definition, you might note that public health gives people and organizations information to help them make choices that inform them and help them improve their health or the health of others. Public health also occurs at different levels.

Individual, organizational, and community levels, and even more broadly at the city-state, national, and international levels. So here are two statements about the mission of public health. The Institute of Medicine says that there is a societal interest in ensuring conditions in which people can be healthy, and we'll come back to the concept of assurance later in the course.

The World Health Organization, or WHO, says public health is about serving the greater good. The maximum benefit for the largest number of people. From these two statements, you can see that public health focuses on groups of people rather than only on individuals.

And at the core of public health, there is this principle of social justice. That people have the right to be healthy and to live in conditions which support their health. So now that we know what public health is, let's review some common key terms.

Clinical care is the prevention, treatment, and management of illness, and the preservation of mental and physical well being through health services. This is all also more commonly referred to as medical care or health care. A determinant, also known as a health determinant, is a factor that contributes to the generation of a trait, such as one's ethnicity or genetic makeup.

But more broadly, the context of people's lives determines their health, and we'll go into more detail about health determinants also later in the course. Epidemic or outbreak, as you can see on the slide, is the occurrence in a community or region of cases of an illness or a specific health related behavior in excess of what you would normally expect to see in that area. An epidemic and outbreak are used interchangeably.

However, epidemic usually refers to a larger geographic distribution of illnesses or health related events. It's basically an epidemic occurs when a disease spreads rapidly to many people. You might also hear the term pandemic, which is kind of an epidemic on steroids.

It often has a global impact, which means people on multiple continents are affected by it, often crossing borders and going into different countries. A health outcome is the result of a medical condition that directly affects a person's life in terms of its quality or length. And think about the health outcomes for somebody who's living with HIV, for example, or who has diabetes.

All right. So now we've come to a knowledge check, and I ask you to fill in the blank with the correct answer. Does public health aim to provide groups of people or individuals with the right to be healthy and live in conditions that support their health?

The answer is groups of people. Public health focuses on populations rather than individuals. The next knowledge check is asking, what is a disease occurrence among a population that is in excess of what's expected for a given time and place?

Is it pandemic, intervention, epidemic or outbreak, or prevention? And the correct answer is epidemic or outbreak. Now we'll take a look at a few historical highlights of public health through the four lenses of sanitation and environmental health, pandemics, disaster response and preparedness, and prevention through policy.

So the first lens will look through encompasses the control of disease and promotion of health through sanitation to ensure a healthy environment. Here are three examples from around the globe of how public health has been implemented to contain infectious disease through environmental measures. So around 500 BCE, it's recorded that the ancient Greeks and Romans actively practiced sanitation measures.

Fast forward approximately two millennia and we see the work begun long ago in Greece continuing in the United Kingdom through the passage of the Public Health Act of 1848, which established a central board of health and placed responsibilities for sanitation in the hands of burroughs. In 1970 in the United States, the administration of President Nixon established the Environmental Protection Agency, which still today protects our health by safeguarding air, water, and land. So next we'll explore pandemics, and you'll recall that these are similar to epidemics except that they affect even larger populations, often across countries and continents.

So influenza, or the flu, has caused pandemics many times during both the distant past and in recent history. Almost a century ago, the Spanish flu infected 500 million people across the world, including in remote Pacific Islands and the Arctic. And it's estimated that it killed between 20 and 50 million people.

More recently, the influenza pandemic in 2009 infected people in 214 countries, causing almost 19,000 confirmed deaths. And while 19,000 confirmed deaths is still many deaths too many, it's nowhere near the type of fatality rate that we saw 100 years or so ago when the Spanish flu ran rampant. So we have made tremendous strides in public health in terms of controlling influenza, but preparing for and controlling the effects of influenza will likely remain top priorities for public health.

Historically, polio was a common and highly feared disease that caused severe illness, including paralysis and even death. Thousands of people lined up to receive the polio vaccine after it was introduced in 1955. An initiative to eradicate polio was launched in 1988 because of outbreaks in more than 125 countries.

And because of those efforts, at this time, polio exists in only a few countries. Lastly, with our last example, during the 1980s, human immunodeficiency virus, or HIV, emerged and spread rapidly across the globe. Public health has responded to this pandemic by developing new ways to diagnose and treat those who are infected.

New infections of HIV are down 20% over the past 10 years, and that's a sign that the public health interventions are successful. So the third area we'll explore is public health's role in preparedness and disaster response, both for natural disasters and human made threats. The use the biological warfare to infect people and animals goes back centuries.

One of the earliest accounts is the use of plague as a weapon of war during the Siege of Caffa in the 14th century AD. And Caffa is now an area where modern day Ukraine is. So back then, attacking Tartar forces likely catapulted dead bodies filled with the infection of plague into the city of their enemy.

This contributed to the spread of the Black Death in that area. During disease outbreaks that could be related to bioterrorism today, the public health community is prepared to distribute lifesaving pharmaceuticals in antidotes, medical supplies, and equipment to locations across the country and even the world. In the wake of the terrorist attacks in the United States on September 11, 2001, which I'm sure all of you remember, public health workers were on the ground at the World Trade Center and at the Pentagon to conduct surveillance to identify outbreaks of disease and health conditions that might have resulted from the attacks.

Public health workers monitored occupational health of first responders and city residents as well as environmental conditions to detect health threats in the aftermath of the attacks. Public health also response to natural disasters. After Hurricane Katrina hit in 2005, public health workers joined disaster relief agencies to provide emergency services and dispatched teams to conduct surveillance for illness and injury among residents in their homes and those who had been relocated to shelters.

So the last lens we'll look through as we view public health history is health policy as a means of prevention. We implement a range of policies across areas of public health to support efforts on a societal level. So as far back as 1500 BCE, Leviticus, the third book of the Hebrew Bible, is believed to be the first written health code in the world.

The book addresses personal and community responsibilities and includes guidance about bodily cleanliness, sexual health behaviors, and protection against contagious diseases, including the isolation of people with leprosy. You might recall hearing about leper colonies back then in history. So in recent decades, we've had tremendous movement in tobacco legislation.

Laws banning smoking in the workplace, restaurants, and other public places have been passed to encourage smokers to quit while also protecting nonsmokers from the effects of secondhand smoke. Also, increases in cigarette taxes have been shown to be a deterrent for buying cigarettes. And you've probably heard the term obesity in the news.

Approximately 60 million Americans-- nearly one third of all adults-- and about one in five children are obese. And doctors usually define obesity as a condition in which a person's weight is 20% or more above normal weight or as a body mass index measurement of 30 or more. Policies and laws related to food labeling, minutes of physical education and resource for children in schools, and even access to healthy foods and safe places to be physically active in communities.

These are all examples of prevention through policy that can impact obesity in a positive way. So to summarize this section of the course, we work in public health to prevent epidemics and the spread of disease and injuries, protect against environmental hazards, promote and encourage healthy behaviors, and respond to disasters and outbreaks. All right.

It's time for another knowledge check. Which of the following events in public health history have been pandemics? And just a hint.

There's more than one answer. Also remember, pandemics are not the same as epidemics. So the correct answers are B and C.

Both influenza and polio are examples of pandemic in the history of public health. So now let's talk about public health in the broader context. As we've seen, public health problems are diverse.

They include infectious diseases, chronic diseases, emergencies, injuries, environmental health problems, as well as a multitude of other health threats. Regardless of the topic though, we take the same approach to a public health problem by following four general steps. First we ask, what is the problem?

In public health, we identify the problem by using surveillance systems to survey and monitor health events and behaviors among a population. And then after we've identified the problem, the next question is, what is the cause of the problem? For example, are there risk factors that certain populations may have that make them more susceptible to disease?

Maybe it's something in the environment or it's certain behaviors that people are practicing. Once we've identified the risk factors related to the problem we ask, well, what intervention works to address the problem? We look at what's worked in the past.

Maybe in addressing the same problem with different populations we look to see if something might work with our population, and we look to see if a proposed intervention would make sense with our affected population. In the last step we ask, how can we implement the intervention? Given the resources we have and what we know about the affected population, will this intervention work?

And this is a very simplified approach. Each of these steps can be spliced into more specific activities, but these are really just the general questions that must be answered to identify a response to a public health problem. Surveillance, risk factor identification, intervention evaluation, and implementation.

Now to implement the public health approach, practitioners use and apply scientific methods that come from a series of core courses. These sciences include public health surveillance, which we use to monitor a public health situation, and epidemiology enables us to determine where diseases originate, how or why they move through populations, how they spread, and how we can prevent them. Public health laboratories have a very important role in supporting public health by performing tests to confirm disease diagnoses.

And laboratories also support public health by conducting research and training that's valuable to the field. As far as informatics goes, as we continue to move from the use of paper documents more to electronic health records, public health informatics continues to increase in importance. Informatics deals with the methods for collecting, compiling, and presenting health information, and it enables us to use electronic data effectively when addressing a public health problem.

And lastly, prevention effectiveness. This is closely linked to public health policy. Prevention effectiveness studies provide important economic information to decision makers to help them compare interventions and then choose one to implement.

So together, these five core sciences can help us protect and promote the public's health by giving public health practitioners the answers that they need. Public health is better able to respond to a given situation or problem by using contributions from each of these sciences. So let's take a look at the public health approach and how can it can be applied to a historical example of an infectious disease.

During the 1800s in London, cholera, an often fatal intestinal disease, was rampant, causing deaths of thousands of people within hours sometimes of first symptoms. So at that time, and this was before bacteria and viruses were recognized as the cause for many illnesses and diseases, popular opinion held that cholera was caused by bad air coming from rotting organic matter. This was known as the miasma or miasma theory.

John Snow, a British physician during that time, he had a different opinion of cholera. He believed that the illness was spreading by way of a contaminated water supply because sewage was being routinely dumped into the Thames River and in cesspools near town wells. Because of his work tracing the route of the cholera outbreak, Dr Snow's often considered the father of modern epidemiology, and his research changed the way we look at disease today.

So let's apply the public health approach to Dr Snow's research of cholera outbreak. So this is a slide of a neighborhood in London, and you'll recall that first we need to identify the public health problem. Snow conducted public health surveillance looking at where those people with cholera lived in London, and he saw that large clusters of cases were occurring in specific areas.

So you'll note the red circle, and you'll see more black dots are in that circle and those represent cholera cases. So the concentration of cholera cases, you'll note, are surrounding the area of Broad. Street and the black dots represent the deaths from cholera.

Notice the higher density of deaths around Broad Street. Snow was assisted back then by a local clergyman by the name of Reverend Henry Whitehead. He was very, very familiar with the neighborhood and people who lived there.

So together-- kind of working separately but then their efforts combined together later on-- they were able to track down and interview surviving cholera victims and their families and geographically map the outbreak. And their efforts highlight the benefit of linking scientific inquiry with engagement of community stakeholders to build the shared ownership of health. So next, Dr Snow examined the data and tried to identify risk factors.

So that is he tried to determine the cause of deaths by using the pattern of where cases were occurring. So this slide illustrates the location of the water pumps in the neighborhood. These are the black boxes.

So on the basis of his previous work, Snow believed that water was a potential source of cholera. So the map reveals that the larger number of cases occurred in areas near water pumps, and this observation prompted Dr Snow to further research the distribution of water pumps in London. And he identified where people who had cholera were drawing their water.

His findings showed that clusters of cholera cases were more commonly located around certain pumps, particularly the pump on Broad Street, smack dab in the center of that graph. So through this research, Dr Snow concluded that drawing water from the Broad Street pump was a primary risk factor for becoming ill with cholera. So after identifying the likely risk factors, the next step in the public health approach is to evaluate potential interventions.

With the water supply from the Broad Street pump identified as the risk factor, Snow then worked to identify interventions to address the problem. He did a lot of continuous research, and from that research he understood that the interventions required to control the cholera outbreak were basically two different interventions. One was to stop exposure to the contaminated water supply in the neighborhood, and then on a larger scale, to stop exposure to the entire supply of contaminated water in the area.

So using the final step of the public health approach, Snow implemented the intervention by getting the handle removed from the Broad Street pump. And that prevented people from drawing their water from that pump because, again, he believed that the supply of water was the source of the contamination. That was a pretty simple but brilliant way of effectively stopping their exposure to the contaminated water supply.

And then, after a very long battle with the politicians and the water companies in the area, Dr Snow finally convinced the British government that water contaminated with sewage, and not smell or bad air coming from the waste itself, that it was the water that was the source of cholera and as well as other diseases. So this resulted in the implementation of policies and laws for water sanitation, and that was an intervention on a much larger scale than just eliminating the threat from any one single water pump. But both interventions had their importance.

All right. It's time for another knowledge check. So this knowledge check just asks you to fill in the blanks with the correct answers.

Each public health core science helps us to blank and blank the public's health by providing public health practitioners with the answers they need. So I'll give you a hint. The answers both start with P's.

Public health core sciences help us protect and promote the public's health. But if you had anything remotely close to protect and promote we'll count that as correct. So with this knowledge check-- this is a matching one.

And just match each component of the public health approach with the questions that they answer. So again, when we ask what is the problem, we're basically talking about surveillance. When we ask what is the cause, we're looking at risk factor determination.

And then we want to know, well, what's going to work? What's going to help to solve this public health problem? That's when we're looking at intervention evaluations.

Possible interventions that we might be able to implement with our particular population. And then lastly, by process of elimination, how do you do it? And that's where you basically decide what are you going to implement.

So this section of the course introduces the core functions and essential services of public health. In 1988, the Institute of Medicine defined three core functions of public health agencies that must be carried out at all levels of government for the overall public health system to work effectively. The three core functions are assessment, policy development, and assurance.

So assessment is knowing what needs to be done, and it's based on the collection and analysis of data. You have to have data before you can do anything else. Policy development is much broader than legislation for one.

It can be guidelines, standard operating procedures, laws, rules, regulations-- all of that is encompassed by policy development. And policy development is based on the information that comes from the assessment function, and it provides the use of such information in policy and decision making. Assurance is making sure that policies and programs get implemented by providing public health services to those who need them.

So if you'll briefly reflect on the mission statement that we discussed earlier of the Institute of Medicine, that public health is assuring conditions in which people can be healthy, this is what this core function is talking about. In this graphic, the three core functions are on the outside of the circle. You'll see assessment on the top right leads to policy development underneath and then assurance on the other side.

The 10 essential public health services are grieved underneath these three core functions. These services are not a prescription for what public health agencies should do, but rather they're really intended to capture the field of public health and communicate what it provides. The strength of a public health system rests on its capacity to effectively deliver the 10 essential services of public health.

So using the issue of tobacco use prevention, let's explore how the essential services can be implemented. Under the function of assessment, what are examples of number one, monitoring health for tobacco use prevention? So one example is to monitor health among segments of the population.

For example, youth. Another example could be monitoring global tobacco use prevention by country. For number two, public health investigates risk factors associated with tobacco use, such as the risk of developing a certain kind of cancer.

Assessing the problem provides more data to inform policy development, and that's the second core function, you'll recall, of public health. And that's, again, on the outside of the circle at the bottom right side. The third essential service, which is under policy development, is to inform, educate, and empower people about health concerns.

So think of different ways that you hear about the danger of using tobacco. Do you hear it from your physician? So you see public service announcements maybe in magazines?

So all of those are examples. People must be informed and educated before they become empowered to make changes, such as quitting tobacco use or never starting at all. On a larger scale, empowerment leads to community mobilization, which is number four.

This might include the work of advocacy groups to rally support around banning smoking in restaurants. And that leads to number five, where policymakers then develop policies to do that work, to accomplish that work. So what other policies regarding tobacco use prevention can you think of?

Often, people might say, well, raising tobacco taxes or not selling tobacco products to people under a certain age. Having a minimum age requirement and enforcing that in retail establishments. And those are all great examples of policies.

After policies are enacted, they must be enforced to have an impact. If they're not enforced, they don't do any good. So enforcement is number six of the essential services of public health.

And using our example, this might be fining someone for smoking on an airplane because smoking is not permitted on airplanes per federal legislation. Number seven is to link people to needed public health services. So an example is to refer smokers to tobacco quit lines or for counseling so that they can stop smoking.

For number eight, we need to ensure that a competent public health workforce is in place to help people quit smoking. And for all of the interventions we develop, it is critical to evaluate them for their effectiveness, both during and at their end. And this is number nine.

So we ask, did the anti-smoking campaign do what it was supposed to do? Did the tobacco cessation program achieve its intended objectives? How successful was the policy that we implemented to raise taxes on tobacco?

Did it deter people from buying cigarettes and thus, help people stop smoking? So evaluation is critical throughout the entire process. The essential services of enforcing laws, linking to care, assuring a competent workforce, and evaluation, they fall under that core function of assurance on the left side of the circle.

And you'll recall that assurance is ensuring provision of services to those who need them. Now you'll note in the middle of this graph there's research. So research is in the middle of all of these core functions and essential services because it's continually informing everything.

So think about as new tobacco products are developed and there are new things coming out all of the time, CDC's laboratories are continuously conducting research on these new products to help us discover their potential negative health effects and help us to look at new products that are being marketed or sold and how we might combat those and battle the tobacco industry. One important point about these essential services is that while they're shown in a very nice graph and that they occur in a sequential order, they actually don't always occur that way in reality. You might have it where you are you doing a couple of the essential services and then you might skip around or you might skip a couple of essential services and move to a different one.

Sometimes things just aren't neatly packaged. Sometimes you might do a few services and then actually loop back and do them over again. And again, with new research continually informing everything, that again prevents a nice chronological, sequential flow.

But if you were to look at this in a sequential order, it does make sense that you'd start with monitoring health and then moving all the way through to insuring competent workforce to actually carry out whatever the interventions are that you've decided to implement to achieve better health of the population. So the core functions of assessment, policy development, and assurance, they must be carried out at all levels of the government for the public health system to function effectively. And this slide shows the core functions at the top and the three different levels of government at the left.

So I'll just go through each level of government and give you the example of assessment, policy development, and assurance. So at the federal level, an example of assessment would be conducting national public health surveillance about tobacco. And then a policy, as we've already discussed, is that they've banned smoking on commercial airline flights.

And then assurance is that the federal government, such as CDC, provides federal grants for anti-smoking research and tobacco use prevention cessation and control. At the state level, states also monitor tobacco use. States have autonomy for increasing tobacco taxes.

If you look across all states, there are a whole bunch of different types of tobacco taxes. They're not all the same amount. That's completely up to the states to regulate that.

And then lastly, assurance. An example of that may be a estate that has a proposition, such as Proposition 99-- I believe that was in California-- funding for campaigns to prevent smoking. At a local level, local communities also report on tobacco use.

So that is a way that they conduct assessment to gather data and diagnose. Then that moves, again, to policy development. So you have county laws that prohibit smoking in bars and restaurants.

Maybe in your county those are good things. And then assurance, at the last level, an example of that at the local level are resources that county or a local health department might develop to help people quit smoking. And they might put those resources in different languages that are representative of the populations of people who live in those communities.

So again, very different levels, but each level has to have a role for all of these functions and services to work together and be successful. All right. So this brings us to a knowledge check.

Which of the following is not a core function of public health? And hopefully you all got this right. The correct answer is authority.

So assurance assessment and policy development are all functions of public health. So here's a second knowledge check. The essential health services of monitoring health and diagnosing and investigating disease relate to which core public health function?

Is it assurance, assessment, or policy development? And remember, it's learning more about the health problem, and so you do that through assessment. And you have to do that before you can do anything else in a meaningful way.

So the next section of this course is about the roles of different groups who have a stake in public health. The field of public health requires stakeholders with skills and intervention programs, policies, research, education, et cetera. Partners include governments, community groups, clinical care providers, employers and businesses, the media, academia.

I could go on and on but those are the main groups, at least that this slide shows, in addition to the infrastructure provided by the government at all levels as we just covered. So what other sectors and fields can you think of that have a stake in public health? When I talk this over with other groups, some of the answers that they provide are transportation, housing, schools, city planning, law enforcement, faith based institutions.

I mean, all of those are great examples of just other partners who have a stake in public health. And some of those are considered nontraditional partners, but our hope is that they will become more traditional and people won't think about only providing with health care providers, for example. Or that basically, we realize that there's a health and all policies approach, which I'll get to in a moment.

Nongovernmental organizations, often referred to as NGOs, play a key role in public health, especially at the community level. NGOs serve many different purposes, from advocacy or education to emergency relief and economic development. [INAUDIBLE] types of NGOs include professional membership organizations, groups that focus on a specific health problem, citizen groups, advocacy groups, and foundations that support health projects and work at the policy level.

So the column at the right just shows an example of each one of these types of organizations. Along with public health, health care plays a vital role in protecting and promoting the health of people. So while the roles of public health and health care are complementary, there are differences that are shown on this slide.

Public health, as we've talked about before, focuses on populations while health care focuses on the individual patient, which is reflected in different guiding ethics for both those areas. Public health focuses on prevention. And while health care is concerned with prevention to some extent, its main focus is more on diagnosing and treating the problem.

Each type of laboratory works jointly, yet public health interacts with the field on behalf of groups of people. And clinical laboratories work with health care providers on behalf of individual patients. And the last row of the table shows that while clinical sciences are of peripheral importance to public health, they are essential to the training of health care providers on the clinical side.

So here are some of the other primary partners in public health. We're seeing the role these days of social media as a vehicle for public discourse on all matter of issues, including public health concerns. Whereas historically, it was more public health agencies and other partners that have educated the public and promoted healthy behaviors through news and entertainment media.

But now, there is more of a self promotion as well as social media continues to take off. Employers and businesses, obviously. They contribute to the public's health by providing health insurance.

Workplaces also have wellness initiatives, such as gym subsidies or workout facilities on site, and these can promote the health of their employees. Government agencies, such as the CDC-- they work in partnership with state, local, and tribal health departments. However, important contributions are made by other governmental agencies at all levels.

City planning departments can include sidewalks and bike paths to promote and support safe places for people to be physically active. Education departments can ensure healthy food options in schools and in vending machines. Similarly, many other government agencies work as partners in public health by including health considerations in their policy development, and this is known as a health and all policies approach.

There's just this concept that regardless of what you do as you're planning, think about how can impact public health. And so that's what I referred to earlier. It says health and all policies.

And really, that opens up the opportunity for public health to partner with a variety-- there's really an endless number of different types of organizations. And lastly, but not leastly, academia educates and trains the public health workforce and conducts research that informs public health and provides a great service to the field. So we have another matching exercise for this knowledge check.

You need to match each stakeholder to its role in public health. So for a vehicle for public health discourse, the correct answer is media. Newspapers, opinion editorials, social media, all media.

Health in all policies, as I said, is something that the government definitely can have an active role in doing, as well as other organizations. But for the purposes of this knowledge check, the correct answer is C, government. Education and training are things that academia contribute to public health.

And the stakeholder that provides wellness initiatives and employee benefits is employers and businesses. So the last section of this course covers determinants of health and explains how they affect public health. As we discussed earlier, certain factors determine a person's state of health.

Scientists typically recognize the same general categories of health determinants for any population, and these are genes and biology, health behaviors, social or societal characteristics, and health services or medical care. So I would like you to think of some examples of each of these broad categories. What are some examples of genes and biology?

You might think of a person's sex or age or immunity levels. For health behaviors it could be whether or not a person is a smoker. What are that person's eating habits?

Whether or not a person takes medications that are prescribed for a chronic condition that person has. Social or societal characteristics. They can include one's ability to work, the quality of schools, where a person lives.

What's the quality of air, water, and sanitation in that person's immediate neighborhood? And then, examples of medical care are insurance coverage and even one's proximity to getting quality health care. This chart is an estimate of how these four major categories of health determinants influence health at the population level.

The chart shows that health care is not the major factor determining our health, yet it represents a substantial portion of the United States budget. Most of what determines our health you'll see at the population level are the social and societal characteristics, whereas genes in and biology, they have the least amount of influence. And then health behaviors, again, a pretty substantial amount.

But it's really the social and societal characteristics and the ecology, including the person's environment, that has the greatest impact. To address the health determinants on this slide that we just discussed, we have to have a plan of attack. A means to effect change.

The health impact pyramid describes such a plan. It shows the impact of different types of public health interventions. So as we move down the pyramid, the public health impact grows greater, and as we move up the pyramid, the amount of individual effort to achieve impact increases.

So let's start at the top. When we start at the top and go down, we can provide counseling and education. We can provide ongoing direct clinical care.

Next, we can provide clinical interventions that require a more limited contact but confer long term protection. That's kind of what preventive medicine does. We can change the context to make individuals default decisions be easy decisions but ones that are the healthiest.

And at the bottom of the pyramid, that addresses the socioeconomic determinants of health. Interventions focusing on the lower level of the pyramid tend to be more effective because they reach broader segments of society and they require less individual effort. This isn't to say that what's at the top of the pyramid is not important because it is, but implementing interventions at all levels of the pyramid, that's what's going to achieve the maximum possible sustained public health benefit.

And a point to emphasize here too is that there are trade offs. We have to sometimes give up resources in one area in order to have a larger impact in another. But let's take a look at some examples of each level of intervention.

So the pyramid illustrates the impact of different types of public health interventions. And again, working our way from the top to the bottom. Counseling and education in clinical settings, public health settings-- they are regarded by some as the essence of public health action.

I went to school and I actually majored in health education and promotion when I got my master's degree in public health. But being at CDC, I've learned a lot about how all of those other areas, including the area at the bottom, really make a substantial impact in interventions. But that's, again, not-- counseling and education-- they're not as effective as we would like.

But that being said, there are times when counseling and education are the only forms of intervention that are available or appropriate. And when they're applied consistently and repeatedly, they can have a positive impact. So moving to clinical interventions, ongoing medical care for a health condition is an example.

For example, in the case of cardiovascular disease, these interventions can have a considerable effect. But we're also limited by a lack of access to certain patients who need that type of care and a lack of adherence to medical instructions and taking prescriptions as prescribed in the real world. So again, that medical care has its limitations.

So in the very middle of the pyramid looking at the intervention level of preventive medicine, let's talk about vaccinations as an example. Vaccinations prevent 2. 5 million deaths among children around the world every year.

So in this case, a single dose or instance of an intervention can have a lifelong effect. So this is an example of a long lasting preventive medicine intervention. The next level down on the pyramid is where we make decisions the default by changing the context in which behaviors occur.

And it makes it more difficult to avoid the intervention. So for example, changing laws to require seat belt use. Making it easier for people to wear their seat belts because if you don't put your seat belt on, you get this really annoying beeping noise until you put it on, so you want to put it on and just make the noise go way.

But it's much easier than it used to be to wear your seat belt. Banning smoking in certain public places is another example. Both of these examples and accomplishments in public health have had a tremendous impact and saved many, many, many lives.

In another basic example, some of the buildings at CDC-- the newer buildings for example-- when you first walk in, the stairs are what you see before you see the elevator. And the stairs have windows and maybe have some plants or some music. So that makes it much more enjoyable and very easy for people to decide to take the stairs instead of going all the way around the corner to find the elevator.

So that's a real basic example of making the healthy decisions the default. At the base of the pyramid are the public health interventions that affect socioeconomic factors. If we can improve the quality of life by helping people out of poverty, providing basic sanitation, improving access to education, helping them get jobs, providing healthy food, medical care, we can greatly improve a population's health.

So it's time for another knowledge check, and I'd like you to just list four determinants of health. Now remember, it can be genes and biology, health behaviors, social societal characteristics, and health services or medical care. In our last knowledge check of the course, just fill in the blanks using the two choices.

For number one, as we move down the health impact pyramid, the public health impact grows greater. Remember, the base of the pyramid is the socioeconomic factors. As we move up the pyramid, the health impact becomes greater in terms of the amount of individual effort that's required.

Again, all levels of the pyramid are important, but it's just a nice framework for thinking about how interventions can be implemented at different levels. Within each of the topics we've covered in this course, underlying all of our actions and decisions is the application of the public health core sciences. I encourage you to build on this introduction to public health by learning more about these core sciences and how they contribute to the field of public health.

Let's review the learning objectives for this session. The course provided content to help you describe the purpose of public health, define some key terms used in public health. You'll recall we talked about epidemics, health determinants.

The course helped you identify prominent events in the history of public health. That's where we looked at a few historical highlights of public health through sanitation and environmental health, pandemics, disaster preparedness and response, and prevention through policy. The course helped you recognize the core public health functions-- those three functions-- and 10 essential services.

You should be able to describe the role of different stakeholders in the field of public health, as well as to list some of the determinants of health. And lastly, you should recognize how individual determinants of health affect population health. Thank you for your attention today for the introduction to public health.

To receive continuing education units, CEU credits, for today's webinar, please complete the webinar evaluation on CDC TRAIN by logging in and looking under My Learning. If you or one of your colleagues were not able to attend today's webinar, an archived version of this webinar will be available on CDC TRAIN in approximately two to three weeks. For further information on CDC webinars, please visit www.

cdc. gov/labtraining. Again, thank you for participating in today's webinar.

Have a positive and healthy afternoon.