Epidemiology focuses on quantifying infections and diseases that range from locally to globally. The former is an epidemic, for example, the seasonal flu epidemic. When an infection spreads worldwide, as COVID-19, it is a pandemic. However, not all work in this field examines the multitude of diseases, like Zika, malaria, ebola, HIV/AIDS, tuberculosis, measles, smallpox, and more. Many of these diseases are rare in the United States. Zika, for example, contracted from mosquitoes has never been reported in the U.S.
The following provides a synopsis of several concentrations in epidemiology. Some of which are available at the master’s and doctorate levels.
This specialty studies an assortment of malignancies, including colorectal, lung, hematologic, ovarian, prostate, and breast cancers. As an epidemiologist, you investigate where there is a high incidence of particular cancer and what are the possible causes. This science dates back centuries; for example, in the 18th century, doctors noticed more patients with breast or scrotum cancer. Regarding the latter, in 1775, Dr. Percival Scott discovered cancer of the scrotum in chimney sweeps. He determined that soot accumulated in the scrotum’s folds; from this conclusion, chimney sweeping became an occupational hazard.
This field studies cardiovascular disease (CVD) from various viewpoints. Scientists analyze the age, lifestyle, eating habits, race, genetics, and more as they establish the causes and effects of CVD in populations. What are the morbidity and mortality rates? What are the risk factors, like high blood pressure, high cholesterol, smoking, obesity, and diabetes, for example? The specialists plot graphs, create charts and scrutinize statistics to see who is most at risk by analyzing data. Research from this epidemiology category reveals that blacks are 2-3 times more likely to die from CVD than whites. Family history, diabetes, sex, ethnicity, socioeconomic status, physical activity, and others are considered in CVD investigation. The results help public health departments educate society on the potential risks to reduce the likelihood of a cardiovascular event.
As one expects, this specialty is concerned about the environmental and ecological exposures that affect people’s health. Analysis of different risks, like air pollution and water quality, seeks to determine what effects air quality has on humans. In 460 BCE, Hippocrates published an essay titled – Airs, Waters, and Places. His purpose was to urge physicians to consider how drinking water, for example, can impact the health of patients. Having safe drinking water remains an issue today.
In this area, scientists analyze the environment’s role in causing illness, growth disorders, disabilities, congenital disabilities, and individuals’ death. In this endeavor, they need to understand the physical, chemical, biological contributors and the damaging effects of these elements on human health.
Epidemiology of Aging
The Johns Hopkins Bloomberg School of Public Health offers a master’s, doctoral, and postdoctoral concentration in the Epidemiology of Aging. Coursework includes epidemiology, biostatistics, and gerontology as students learn how physical and cognitive functioning change with age. These subjects are apropos as the world’s population has more adults over 65 than children five and younger.
Epidemiologists and other scientists have performed numerous studies around the world. The increasing percentage of the elderly affords unlimited topics to research. For example, in Japan, a paper published in 2015 projected that 30% of the population would be 65 or older by 2025. This figure presents challenges for acute medical care, long-term care, employment, and housing. Another concern was the education of physicians trained in gerontology to meet the aging population.
Aging and neuroepidemiology can be one subfield. The latter addresses diseases of the nervous system.
Infectious Disease Epidemiology
This subfield probes the influence of pathogens on public health. A pathogen is any disease-causing organism, of which there are four standard types:
- Viruses – consist of genetic code, like DNA or RNA.
- Bacteria – Single-cell microorganisms: not all of them cause infections
- Fungi – millions exist on the planet, with 300 cause illness
- Parasites – infections from these organisms are more prevalent in tropical and subtropical regions
Duties in this specialty involve investigating the origin, rate of spread, and the means of transmission. What are the duration, susceptibility, and patterns of the infection? These questions concern the epidemiologist in the event of an epidemic or pandemic. Working in concert with public health officials, the medical personnel share information with the epidemiologists to contain the illness and safeguard society.
Infectious disease epidemiology studies various infections, for example, sexually transmitted diseases, diarrheal pathogens, and tuberculosis. In July 2019, people in several states developed stomach cramps, diarrhea, and vomiting. The FDA (Food and Drug Administration) and the CDC (Centers for Disease Control and Prevention) linked the outbreak to a specific flour brand. Epidemiology played a role in the investigation by documenting the prevalence and concentration of common symptoms to determine the cause.
The University of Washington School of Public Health has research areas in this specialty.
Epidemiological methods study the relationship of diet to health and disease in humans. How does what a person or population eats affect various health outcomes, such as infectious diseases, chronic diseases, cancer, longevity, and congenital malformations.
An example from the sixteenth to the eighteenth century is the bleeding gums, swollen inflamed joints, and sometimes death in sailors. Eventually, the discovery was made that vegetables and fruits could cure these symptoms, known as scurvy. Consequently, lemons and oranges became the most effective remedy because of the molecular structure of vitamin C.
The discovery of the association of scurvy and lack of vitamin C originated in 1747 when Captain James Lind noticed the mysterious disease among the HMS Salisbury sailors. Lind decided to give the sailors six different diets. Those who ate the most fruit had the quickest relief from their bleeding gums and irritated joints!
Nutritional epidemiology plays a crucial part in the public health system by disseminating information for healthy eating habits.
The information above is not an all-inclusive list. Other epidemiology subfields are clinical, genetic, occupational, reproductive, pediatric, global health, violence/injury, and psychiatric.