1.5: Defining Public Health
According to one of the early innovators of public health, Charles Edward. A. Winslow, the definition of public health is:
The science and the art of preventing disease, prolonging life, and promoting physical health and efficiency through organized community efforts for the sanitation of the environment, the control of community infections, and education of the individual in principles of personal hygiene, the organization of medical and nursing services for the early diagnosis and preventive treatment of disease, and the development of the social machinery which will ensure to every individual in the community a standard of living adequate for the maintenance of health. (Schneider, 2020, p. 4)
A unique characteristic of this definition of public health identifies a minimum “assurance” of the opportunity to maintain personal health - an adequate standard of living. In other words, we owe it to each other to make sure that each person has the opportunity to live a healthy life. The World Health Organization takes this collective obligation further in defining health as a human right:
“The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition.”
( Constitution of the World Health Organization , n.d.)
One particular part of public health attempts to identify causes and risk factors of diseases and illness, or negative health outcomes. A health outcome is any change in health status, positive or negative. Negative or “poor” health outcomes are those that result in disease, injury, or death. Positive health outcomes could include being alive and living longer, not contracting an infectious disease or improving HQOL. Epidemiology is the study of how widespread a health outcome is, and its etiology or causes (Centers for Disease Control and Prevention, 2018). Epidemiologists research the distribution of diseases as well as what factors might affect a particular population’s health outcomes (we’ll discuss epidemiology more in future chapters). Factors that affect health outcomes are also called determinants of health . These determinants may increase (risk factor) or decrease (protective factor) a person’s risk for developing a specific disease, either independently or in combination with other factors. Determinants of health typically fit into the following 5 categories (Seabert et al., 2021, p. 5):
- Biological factors: genetics, personal or family history of illness or infection, sex assigned at birth, hormone levels, age, etc.
- Behavioral factors: nutrition, physical activity, smoking, alcohol and drug use, seatbelt wearing, sexual activity, etc.
- Social-Economic factors: income, socioeconomic status (SES), education, social support, systemic racism, discrimination, access to preventative care, etc.
- Environmental factors: geography, neighborhood structure, safety, environmental hazards, clean air/water/sanitation, etc.
- Medical care: the type and quality of medical treatment available.
A single risk factor is rarely a stand-alone cause of a specific health outcome. Rather, determinants of health are often identified in combination as risk factors. Take the example of the behavior of cigarette smoking. It has been well established that cigarette smoking is a factor in 80-90% of all lung cancer deaths, and smoking also increases the risk of bladder, pancreatic, and other cancers, as well as the risk of coronary heart disease and stroke ( What Are the Risk Factors for Lung Cancer? , 2023, Diseases and Death , 2022). Since smoking is a behavior, it logically fits into the behavioral category above. However, this behavior is also connected to other determinants of health. The nicotine present in cigarette smoke is highly addictive, so the smoking behavior is influenced by the biological dependency created after just a few cigarettes. Still other social factors influence the likelihood of someone picking up the habit of cigarette smoking - such as cultural attitudes toward smoking, or personal knowledge about the harms of smoking. Many smokers indicate that smoking reduces stress, and stress may be higher in communities with less job security or public safety. There are likely environmental factors such as access to cigarettes that could also be involved. If we only look at the disease of lung cancer, there are also other environmental exposures (such as asbestos) which increase the risk of developing the disease. So the process of identifying risk factors and determinants of health outcomes can become complicated.
Another example, this time of a protective effect, would be physical activity. Individuals who regularly engage in physical activity tend to have lower risks of chronic diseases and lower their risk of developing severe responses to some infectious disease as well, like COVID-19 (Steenkamp et al., 2022). Similar factors may influence an individual's physical activity levels - such as family and cultural attitudes toward physical activity, socioeconomic status and leisure time, neighborhood safety and greenspace, education level, and whether the person is living with musculoskeletal conditions or disabilities. However, physical activity alone does not prevent all cases of chronic disease. And other determinants like genetics, healthy nutrition, clean air and regular medical screenings may work in conjunction with physical activity to protect against chronic disease.
Public health research often examines the community or population at risk for developing a certain disease, and then works to identify and address commonly-shared determinants associated with that disease. Because public health is focused on prevention, this includes developing public policies that attempt to reduce the incidence or prevalence of a certain disease, ensuring resources are available to respond to health issues and emergencies, and implementing programs and interventions to reduce risk factors and increase protective factors in those determinants of health. All of these actions depend on appropriate research in order to justify their funding and ensure they are working effectively, so gathering and analyzing data on health outcomes and determinants is at the heart of public health. We’ll discuss the different roles and responsibilities of public health later on in this text.