Epidemiology For Dummies
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This Cheat Sheet simplifies a few topics that you may encounter in your epidemiology coursework. For example, epidemiologic study design is important for conducting research.

Furthermore, when working in public health, you want to help people prevent disease, and educating the populations you serve about making healthy food choices is a great way to do so.

Epidemiologic study types

Here are some tips to help you choose an epidemiologic study design based on your research topic and available resources. The following lists epidemiological study types and the situations for which they’re best suited.

Ecological study

  • You want to compare multiple country data
  • It’s difficult or impossible to gather individual-level data

Cross-sectional study

  • You want to conduct a prevalence study.
  • You want to conduct a population survey.

Case-control study

  • The disease is rare.
  • You want to study the cause of death.
  • You want to identify risk factors.
  • You want to conduct a study in a short time with a limited budget.
  • You have access to patients’ past records.

Cohort study

  • You have a large group of people who can be followed over time.
  • Attrition rate is minimum because the study population in the cohort wouldn’t move often.
  • You have good amount of resources in terms of funds and time.
  • You want to control confounding variable and biases more efficiently so that the results are more reliable.

Experimental study

  • You want to evaluate the effect of a treatment or other intervention.
  • You have comparison groups.
  • You want to proof a hypothesis that isn’t otherwise possible to study.
  • You expect accurate results from a controlled study.

Clinical trials

  • Drug trial: To study the efficacy and safety of a new drug
  • Hospital-based interventions
  • Community-based interventions
  • Blinded, controlled studies
  • Control for confounders
  • Control biases

Promoting fruits as a public health preventative measure

Fruits are natural sources of healthy food — they’re low calorie and low sodium with a negligible amount of fat. With more than 2,000 varieties of fruits, you may wonder which fruits are better than others. When working in public health, one of your roles may be in educating the public about eating foods that are good for them. The following fruits are delicious and healthy:
  • Apples: They come with many nutrients, including soluble and insoluble fibers, such as pectin, hemicellulose, and cellulose; vitamin C; and plant polyphenols, which fight against diseases. Most polyphenols are just beneath the skin. Apples protect people from diseases like heart disease, diabetes, cancer, stroke, obesity, and neurological disorders.
  • Avocados: They’re high in healthy fats and low in natural sugars. The vitamin and mineral contents of avocados include vitamin C, vitamin B6, folate, vitamin E, vitamin K, and potassium. They’re also good source of fibers. Two carotenoids known as lutein and zeaxanthin help eye health. Avocados contain monounsaturated fat that improves a person’s good cholesterol (HDL) and decreases triglycerides, without raising the bad cholesterol (LDL).
  • Bananas: They’re an excellent source of potassium — 7 percent of the daily value (DV)); vitamin C — 12 percent of the DV; vitamin B6 — 27 percent of the DV; and magnesium — 8 percent of the DV. Bananas contain about 60 to 80 percent of their carbohydrates as indigestible carbohydrates, which contain prebiotic properties. Prebiotics help in the formation of probiotic bacteria found in yogurt. Green, unripe bananas are a good source of the dietary fiber pectin.
  • Blueberries: They’re high in flavonoids that give blueberries their characteristic blue-purple color. This compound helps fight cell-damaging free radicals that can lead to disease.
  • Cherries: Cherries are rich in fiber, potassium, and antioxidant plant compounds, such as anthocyanins and hydroxycinnamates, which help protect the body from oxidative stress. They’re a good source of serotonin, tryptophan, and melatonin, which support good mood and sleep.
  • Dragon fruit: Dragon fruit is a good source of fiber, iron, magnesium, and vitamins C and E. It’s also an excellent source of carotenoids, such as lycopene and beta-carotene.
  • Mangoes: They’re an excellent source of potassium, folate, fiber, and vitamins A, C, B6, E, and K. Mangoes are high in mangiferin, a potent antioxidant. They’re rich in numerous plant polyphenols that have antioxidant and anti-inflammatory properties.
  • Oranges: They can provide 91 percent of the DV for vitamin C. They’re also high in potassium, folate, thiamine (vitamin B1), fiber, and plant polyphenols.
  • Pineapples: One cup (165 grams) of pineapple provides 88 percent of the DV for vitamin C and 73 percent of the DV for manganese. Magnesium helps in controlling blood sugar, and it also acts as an antioxidant. Pineapples contain a number of polyphenolic compounds that have antioxidant and anti-inflammatory properties.
  • Strawberries: They’re delicious and highly nutritious, a good source of vitamin C, folate and magnesium. They’re full of plant polyphenols that act as antioxidants, such as flavonoids, phenolic acids, lignans, and tannins. They’re high in anthocyanins, ellagitannins, and proanthocyanidins, which reduce the risk of chronic diseases.

Types of bioterrorist agents

Traditionally, the purpose of surveillance was to prevent epidemics and the spread of selected diseases, to respond to disasters and assisting communities in recovery, to protect against environmental hazards, and to evaluate an intervention. Many public health emergencies are readily apparent, but other threats may not be visible until they affect a large number of people’s lives. The threat to human lives changed dramatically after the terrorist attacks on the World Trade Center and the Pentagon on September 11, 2001, and bioterrorism events spreading through the U.S. postal system thereafter.

Being prepared and planning against impending bioterrorist threats is important. Therefore, the scope of surveillance has expanded to a type called event-based surveillance. It involves the use of reports, stories, rumors, and other information needed to identify events that pose a potential threat to public health.

Preparedness and planning can’t eliminate any biological (viruses, bacteria, or their toxins) agents, chemical compounds, and radiation materials that can cause casualty threats. However, preparedness and planning will help you identify risk factors or events, track disease trends, determine action items, and target interventions. The agents mentioned here can be released by way of the air (aerosols), food, water, insects, or direct contacts. Biological agents with bioterrorism potential are divided in to the three following categories.

Category A agents

These organisms pose a risk to national security. They transmit quickly, easily affecting a large group of people and killing many people. The diseases caused by these agents are as follows:
  • Anthrax caused by Bacillus anthracis
  • Botulism caused by Clostridium botulinum
  • Plague caused by Yersinia pestis
  • Smallpox caused by variola major
  • Tularemia caused by Francisella tularensis
  • Viral hemorrhagic fever caused by filoviruses (for example Ebola) and arenaviruses (for example Lassa fever)

Category B agents

These are the second highest priority organisms. They’re also transmitted from one person to another but not as readily as Category A agents. Due to the moderate rate of morbidity and mortality, the surveillance program for these agents requires the specific enhancement of CDC’s diagnostic capacity. Here are the selected diseases/agents in this category:
  • Brucellosis caused by Brucella species
  • Epsilon toxin of Clostridium perfringens
  • Food safety threats due to Salmonella species, E. coli 0157:H7, Shigella species
  • Psittacosis caused by Chlamydia psittaci
  • Q fever caused by Coxiella burnetii
  • Ricin toxin from castor beans
  • Staphylococcal enterotoxin B
  • Typhus fever caused by Rickettsia prowazakii
  • Viral encephalitis caused by alphaviruses
  • Water safety threats caused by Vibrio cholerae, Cryptosporidium

Category C agents

These agents can be engineered for mass dissemination. They include emerging infectious diseases caused by Nipah virus or hantavirus. Chemical agents with bioterrorism potential include the following:

  • Biotoxins: Abrin, brevetoxin, colchicine, digitalis, nicotine, ricin, tetrodotoxin, and others
  • Blister agents: Applied through eyes, respiratory tract, and skin; include distilled mustard, mustard gas, nitrogen mustard, phosgene oxime, and others
  • Blood agents: Arsenic, carbon monoxide, cyanogen chloride, hydrogen cyanide, potassium cyanide, sodium cyanide, and sodium monofluoroacetate.
  • Choking agents: Ammonia, bromide, chlorine, hydrogen chloride, methyl bromide, methyl isocyanate, phosgene, sulfuryl fluoride, and others
  • Long-acting anticoagulants: Super warfarin
  • Metals: Arsenic, mercury, and thallium
  • Nerve agents: Sarin, soman, tabun, and others
  • Tear gas
  • Toxic alcohols: Can damage a person’s heart, kidneys, and nervous system
Bioterrorism threats represent a special challenge for public health. The prevention against bioterrorism require a coordinated effort that include people from many areas, such as criminal justice, military, and intelligence agencies.

About This Article

This article is from the book:

About the book author:

Amal K. Mitra, MD, DrPH, is an internationally recognized scientist and public health leader with more than 25 years of experience in higher education and health research. He is a professor of epidemiology and biostatistics at Jackson State University in Mississippi.

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