Where do illnesses come from? Why do some people become sick while others remain well? Which diseases are most prevalent in a given city, state or community, or among a particular population group? These and other relevant questions have been important to answer for centuries, and they have become even more prominent since the rise of the COVID-19 pandemic.
Each of these questions is critical to the field of public health, in which professionals seek to promote the physical health and well-being of entire populations. To help answer these questions, and ultimately to advance better health outcomes, public health experts rely on the scientific disciplines of epidemiology and biostatistics.
These disciplines, while overlapping in several ways, are distinct from each other. This article will consider the similarities and differences in epidemiology vs. biostatistics, as well as the roles that both disciplines play in promoting public health.
What Is Epidemiology?
Epidemiology is a health care discipline with an important distinction: The “patient” isn’t defined as being an individual, but rather as an entire community or population. Specifically, epidemiology uses science, systems-thinking and data to determine the underlying causes of different diseases and health outcomes in a population.
Epidemiologists tend to focus on two areas: distribution and determination.
- Distribution refers to the frequency of a particular disease or health outcome and to any patterns or trends that may be identified
- Determination is more concerned with cause and effect: What are the risk factors associated with a disease? What are its underlying causes?
Epidemiologists focus narrowly on a particular population — whether it be a nation, a state, a city or even a small neighborhood. Additionally, epidemiologists study any and all events that pertain to population health. In other words, epidemiologists study not just diseases, but also any external factors that cause people to become sick, injured or impaired.
With a full understanding of distribution and determination, epidemiologists can implement strategies that can treat, control and ultimately prevent the spread of disease.
The Scope of Epidemiology
The work of epidemiologists encompasses a wide range of issues. The Centers for Disease Control and Prevention (CDC) lists six categories in epidemiology.
Environmental Issues
Epidemiologists may study any environmental exposures that contribute to population sickness or wellness. For example, what’s the local air quality? Are there potent allergens or asthma triggers? Does the local water supply contain any harmful substances?
Infectious Diseases
Epidemiology concerns itself with infectious diseases as well, which may include anything from foodborne illness to seasonal flu. Historically, epidemiology has played a vital role in developing a clear understanding of pandemics such as typhoid and cholera.
Noninfectious Diseases
Noninfectious diseases can include a local risk for a particular type of cancer, birth defects or a high rate of diabetes in a particular community. Epidemiologists may study the potential factors that contribute to these and other conditions.
Injuries
Epidemiology also includes the study of injuries, such as local rates of gun violence or homicide. Researchers consider factors that make these injuries more likely and also explore their impact on the community’s physical and emotional well-being.
Natural Disasters
A natural disaster’s short- and long-term effects may warrant epidemiological study. Natural disasters can include anything from hurricanes to wildfires to earthquakes.
Acts of Terror
A final category for epidemiological study is terrorism. According to the CDC, professionals in the epidemiology field may study the effects of incidents like the World Trade Center attacks or biochemical weapons deployment.
What Do Epidemiologists Study?
The process that epidemiologists employ involves several core metrics. Each is used to evaluate different health outcomes and develop strategies to promote public health.
Epidemiology Metrics
Epidemiologists monitor four essential metrics to understand population health outcomes: disease dispersal, disease factors, disease populations and health-related impact.
Disease Dispersal
Epidemiologists are concerned with how common or rare a disease may be as well as any potential patterns to its development. For example, does the disease occur more frequently in men or women? Does it occur in certain age groups? Does it occur during certain seasons?
Disease Factors
Epidemiologists also look at some of the underlying factors that make an individual or a population more prone to adverse health outcomes. These factors could be physical, such as climate- or geography-related; biological, such as disease transmission via insects; or socioeconomic, including variables such as health service availability or sanitation.
Disease Populations
Epidemiologists may ask which populations does a disease seem to most acutely affect? Has the disease spread beyond a particular neighborhood, city or state, or is it more contained?
Health-Related Impact
Epidemiologists study the overall impact of a disease or health event on a population’s physical and mental well-being. Epidemiologists may also consider any related social or economic disruptions.
Resources on the Study of Epidemiology
For further exploration of what epidemiologists study, consider the following resources.
- Live Science, “What Is Epidemiology?” Find out more about the role of “disease detectives” who work in this public health field.
- Science Focus, “Epidemiology: A Timeline of Discoveries.” Explore the history of key medical breakthroughs that mitigated the effects of various public health risks.
- Nature, “How Epidemiology Has Shaped the COVID Pandemic.” A progress report highlighting epidemiology’s role in the global pandemic response.
What Is the Role of Epidemiology in Public Health?
History provides many examples of how epidemiologists have played a role in promoting health, curbing the spread of disease and developing strategies to address widespread illnesses.
Foodborne and Waterborne Diseases
Epidemiologists have performed highly consequential work connecting rampant diseases with environmental causes, such as pollutants in local food supplies and water sources.
Thanks to epidemiologists, we know that typhoid is widely associated with poor sanitation and dirty water. This information is useful not only in identifying high-risk areas but also in preventing a typhoid outbreak.
Epidemiologists also discovered that cholera comes from contaminants found in feces, which can sometimes be spread to food and water sources due to overall lack of sanitation and hygiene.
The work of epidemiologists in determining the sources of food- and waterborne disease can lead to technological advances that produce safer water and better sanitation.
Viral Infections
Epidemiologists have done important work tracing infectious diseases. Consider three examples.
- As the CDC points out, researchers played a major role in exploring the genetic makeup of the 1918 influenza epidemic. Epidemiologists used that information to better prepare for future disease outbreaks.
- Epidemiology has also provided an overview of the global HIV crisis, helping researchers identify trends, patterns, “hot spots” and means for disease control. The World Health Organization (WHO) provides a detailed summary of this work.
- More recently, epidemiologists around the globe concentrated their efforts to trace the cause of COVID-19, determining modes of transmission and providing recommendations on controlling its spread, which has included vaccination advocacy and fighting the dissemination of misinformation. The WHO provides weekly updates of epidemiological efforts to combat COVID-19 around the world.
Famous Epidemiologists
Many famous epidemiologists have contributed to the field of public health. A few noteworthy examples include the following:
- John Snow was a British physician whose cholera studies proved foundational for modern-day epidemiology.
- The American virologist Nathan Wolfe performed innovative studies on the nature of infectious disease spread.
- Thomas Francis Jr., an American microbiologist, helped isolate different influenza strains, enabling more targeted treatment.
- Another American researcher, Paul Farmer, is noted not only for his work in epidemiology but also for his advocacy for robust health care in underserved populations.
Resources on the Role of Epidemiology in Public Health
To find out more about epidemiology’s role in public health, check out these resources:
- Nature Research, “A Metabolic Handbook for the COVID-19 Pandemic.” Check out this example of epidemiologists in action.
- Centers for Disease Control and Prevention, Enteric Diseases Epidemiology Branch. Learn more about what the CDC does to trace foodborne and waterborne illnesses.
- Molecules, “COVID-19: A Global Challenge with Old History, Epidemiology and Progress So Far.” Discover how epidemiologists apply historical research to contemporary outbreaks.
What Is Biostatistics?
Biostatistics is often considered in conjunction with epidemiology. While they are related, these disciplines aren’t the same, and it’s important to understand the differences.
Biostatistics, which is also called biometry, studies biological phenomena through the use of mathematical principles, statistical modeling, methodologies and processes. A biostatistician may design a biological experiment, and then collect and interpret the data that the experiment yields.
Biostatistics provides the foundation of much epidemiological research. In other words, epidemiologists often use biostatistical principles and methods to draw data-backed mathematical conclusions about population health issues.
What Do Biostatisticians Study?
Biostatisticians may study diseases, disorders and health risks associated with certain behaviors or the local environment. They are typically employed by health departments on the federal, state or regional level.
Biostatistics Methods and Procedures
Biostatistics is considered one of the foundational disciplines in public health. Specifically, biostatisticians conduct quantitative and qualitative research to help identify population health trends and risk factors. This work may involve several methodologies, including the following:
- Clinical trials
- Focus groups
- Surveys
- Case studies
- Field observation
- Laboratory experiments
Through these and other methodologies, biostatisticians gather and analyze data, which may lead them to statistically significant conclusions about how different diseases originate or spread. These findings often provide clues as to how these diseases may be controlled, prevented or eradicated.
Biostatistics in Action
For examples of what biostatistics may look like in practice, consider the following:
- Some statistical researchers may focus on a particular population, such as infants or older adults, and study conditions that seem especially prevalent among the demographic in question.
- Others in the biostatistics field may look at a specific health concern, like obesity or diabetes, using statistical trends to identify possible causes or risk factors.
- Biostatistics can also encompass the study of environmental factors or the effects of a particular therapy or clinical intervention on patient outcomes.
- Some biostatisticians may apply their methodologies to various treatment strategies to determine their overall effectiveness or measure short- and long-term side effects.
How Findings Are Presented
The results of biostatistical studies may be shared with other researchers in the epidemiology field or even be made available to the general public. Typically, this information is presented in one of the following ways:
- Research papers
- Journal articles
- Conference presentations
- Published books
What Is the Role of Biostatistics in Public Health?
Biostatistics has been used throughout history to improve public health outcomes. Here we consider several case studies on the public health role of biostatistics.
Cancer Research
Biostatisticians have played a longstanding role in oncology, designing experiments to better understand how and why cancers form and how they may be effectively treated. Biostatistical research in oncology includes a wide range of clinical trials, focusing on patient populations of different sizes and at different stages of treatment. Through these trials, researchers have developed a greater understanding of genetic markers that make a person more or less at risk for different kinds of cancer.
Chronic Diseases
Biostatisticians also build statistical models to understand various factors that may contribute to chronic diseases apart from cancer, such as heart disease, diabetes or stroke. Their findings can be applied to strategies to mitigate or prevent these conditions.
Environmental Factors in Public Health
Additionally, public health professionals who work in biostatistics have conducted important investigations on how air pollution, water contamination and other environmental factors may impact a local population’s well-being. Through surveys, clinical trials and field observation, biostatisticians have made important discoveries about toxic substances and hazardous waste and their possible impact on different populations, links between local infrastructure and population health, and even the effects of climate change on different communities.
Statistical Genetics
A significant subdiscipline of biostatistics is statistical genetics. Researchers in statistical genetics use different statistical methods to draw conclusions based on genetic data. Statistical genetics provides insight into how different genes:
- Affect particular diseases or health conditions
- Impact a “normal” phenotype
- Have evolved and adapted, specifically within particular demographics
The inferences can help clinicians identify patients who may be at a higher risk for certain conditions, making preventive treatment a possibility.
Human Growth and Development
Biostatistical research has also provided benchmarks and reference points for normal human growth and development. By surveying growth trends across broad sample sizes, researchers have developed a better understanding of how children and adolescents grow, which factors support healthy growth and which factors may stunt it.
Resources on Biostatistics in Public Health
To find out more about biostatistics, especially regarding population health, take a look at these resources:
- Nature Research, Biostatistics. View some of the latest biostatistics news and findings.
- Division of Cancer Epidemiology and Genetics, Biostatistics Branch. Gain further insight into the role genetic research plays in the study and treatment of cancer.
- Centers for Disease Control and Prevention, COVID-19 Data from the National Center for Health Statistics. A source for CDC data regarding COVID-19’s effect on metrics such as deaths, care access and mental health.
What Is the Difference Between Epidemiology and Biostatistics?
Biostatistics and epidemiology are often seen as closely related. There is a reason for this. Both fields consider population health concerns, and both fields have the ultimate goal of promoting overall health and disease prevention in a specific community.
Biostatistics may be understood as one of the tools that epidemiology employs; that is, an epidemiologist may use biostatistics principles to help process data and make helpful inferences.
Despite their overlaps, there are many differences to explore when comparing epidemiology vs. biostatistics:
- Epidemiologists typically focus on pathogens and epidemics; they are concerned with specific health-related events. Biostatisticians, however, focus on broader biological issues, such as those related to genetics.
- Epidemiologists will usually specialize in the cause of diseases and the different factors that contribute to population health problems. Meanwhile, biostatisticians typically specialize in the effects of health issues, for example, the implications of genetics, the environment or biological factors.
- Epidemiologists can be involved in community outreach programs, which require strong teaching skills. This type of public education effort isn’t usually part of the biostatistician’s job description.
- Biostatistician roles, even more so than those of epidemiologist roles, typically require strong computer skills and project management competencies.
Promoting Public Health Through Scientific Study
To keep communities safe and healthy, public officials need to have a clear understanding of different factors that impact the health of individuals and the population as a whole. Through scientific inquiry, both epidemiology and biostatistics provide this understanding and lay a foundation for greater health and well-being throughout our communities.
Recommended Reading:
What Are the Top Public Health Concerns Today and How Are They Determined?
What Is the Difference Between Public Health and Community Health?
Why is Public Health Important?
Infographic Sources:
Centers for Disease Control and Prevention, Epidemiology
PayScale, Average Biostatistician Salary
U.S. Bureau of Labor Statistics, Epidemiologists
U.S. Bureau of Labor Statistics, Mathematicians and Statisticians