103 Questions
What is the meaning of the Greek root 'epi' in the term 'epidemiology'?
upon
What is epidemiology usually defined as?
The study of disease in a population
What is the focus of classical epidemiology?
Community origins of health problems
What is the difference between classical epidemiology and clinical epidemiology?
Classical epidemiology focuses on populations, while clinical epidemiology focuses on individuals
At which level does epidemiology primarily operate?
Level of populations
What is the primary goal of classical epidemiologists?
To discover risk factors that might be altered to prevent disease
What is the relationship between the four levels of studying disease?
They are related and can be coordinated to maximize understanding
What do investigators involved in clinical epidemiology often use?
Research designs and statistical tools similar to classical epidemiologists
What is the primary focus of clinical epidemiologists?
Studying patients in healthcare settings
What is the main difference between infectious disease epidemiology and chronic disease epidemiology?
The laboratory support required
What is the goal of intervention in the natural history of a disease?
To alter the natural history of the disease in a favorable way
What is the term for the cause or origin of a disease or abnormal condition?
Etiology
During which stage of disease development can early intervention prevent the disease process from starting?
Predisease stage
What type of epidemiology looks for patterns of signs and symptoms that might indicate an origin in bioterrorism?
Syndromic epidemiology
What is the term for the way a disease progresses in the absence of medical or public health intervention?
Natural history
What is the primary goal of epidemiologists in healthcare settings?
To improve patient care
What is the term for the body of knowledge acquired by using epidemiologic methods?
The epidemiology of disease
What is the main distinction between primary, secondary, and tertiary prevention?
The timing of intervention
What is the primary cause of osteomalacia?
Vitamin D deficiency
What is the role of ergosterol in the skin?
It is an important source of D vitamins
What is the consequence of osteomalacia on future pregnancies?
It causes the pelvis to become distorted
What is the primary goal of epidemiologists?
To discover the social and behavioral causes of disease
What is the role of the vector in the case of measles?
It is relatively unimportant
What is the primary factor in the spread of malaria?
The vector
What is the relationship between nutrition and immune status?
They can work synergistically
What is the effect of marasmus on the outcome of measles?
It increases the risk of complications
What is the category of biologic agents that includes allergens and infectious organisms?
Biologic agents
What is the consequence of a woman's diet being deficient in vitamin D during puberty?
She may develop osteomalacia
What is an example of physical agents that can cause harm to humans?
Kinetic energy, radiation, and heat
How does the environment influence the probability and circumstances of contact between the host and the agent?
It increases the probability of contact between the host and the agent
What is an example of a vector of disease?
A mosquito associated with the spread of malaria
What is required for a vector to be an effective transmitter of disease?
A specific relationship between the vector, the agent, and the environment
What are examples of extrinsic factors that contribute to cancer cases?
Man-made chemicals, viral infections, nutritional deficiencies, and reproductive activities
What is the primary method used by epidemiologists to estimate the percentage of deaths caused by preventable risk factors in a country?
Epidemiologic methods
What is an example of a social factor that influences the nutritional and vaccine status of a society's members?
Political structure
What is the role of the environment in the transmission of disease?
It provides a conducive environment for the agent to breed and come into contact with the host
What is a common misconception about the phrase 'extrinsic factors' in the context of cancer prevention?
It only refers to man-made chemicals
What is a consequence of the long-term use of corticosteroids and cancer chemotherapy?
Severe immunodeficiency
According to Denis Burkitt, what is a characteristic of populations with a high fiber intake?
Large stools and small hospitals
What is the name of the disease that Burkitt suggested might be prevented or reduced by a high intake of dietary fiber?
Coronary heart disease
What is the role of genetic epidemiology?
To examine the interaction of genes with environmental factors
What is heritability?
The contribution of genes to disease
What is the term for the cause or origin of a disease or abnormal condition?
Etiology
What is the benefit of genetic screening in newborns?
Therapy can be instituted early enough to be beneficial
What is the primary factor contributing to the increasing proportion of genetic disease?
Decrease in the incidence of non-inherited disease
What is the primary goal of the two methods described in determining the percentage of cancers with identifiable causes?
To estimate the total percentage of cancers having identifiable causes
What does the BEINGS acronym stand for?
Biologic, Environmental, Immunologic, Nutritional, Genetic, and Spiritual factors
Which of the following biologic factors is a risk factor for disease?
All of the above
What is the percentage of myocardial infarction (MI) cases among smokers attributed to cigarette smoking?
50%
What is the health effect of obesity and overweight?
Increasing the prevalence of type 2 diabetes
What is the focus of the second method described in estimating the total percentage of cancers having identifiable causes?
Examining annual age-specific and gender-specific cancer incidence rates in countries with low rates
What is one potential health benefit of identifying individuals with specific genetic risks?
Responding particularly well to specific drugs
What is a common cause of adverse events in hospitals?
Medication errors
What is the potential consequence of unnecessary or inappropriate diagnostic or surgical procedures?
Illness or disease
What is the term for the phenomenon where a vaccine diminishes an immunized person’s ability to spread a disease, leading to reduced disease transmission?
Herd immunity
What is a factor that can influence an individual's ability to resist noxious stressors?
Social support
What is the name of the bacterium that causes legionnaires’ disease?
Legionella pneumophila
What is a potential benefit of strong religious faith on health?
Better health and quality of life
What is the primary goal of modifying human behavior in health promotion?
To prevent premature death
What is the name of the disease that is the first infectious disease known to have been eradicated from the globe?
Smallpox
What is a characteristic of Mormons and Seventh-Day Adventists that may contribute to their lower-than-average death rates?
Prohibited behaviors such as smoking and drinking
What is the term for disease that occurs as a result of medical treatment or diagnostic procedures?
Iatrogenic disease
What is the term for the temporary weakening of the immune system after some infections or vaccinations?
Transient immune deficiency
What is the potential benefit of identifying susceptibility genes?
Receiving targeted medical treatment
What is the result of a deficiency in the immune system, which can be caused by genetic abnormalities and other factors?
Immunodeficiency
What is often the outcome of the initial hypotheses about disease causation provided by epidemiologists?
Suggestion of ways to prevent diseases
What is a consequence of the rapid growth in world population and increased travel and contact with new ecosystems?
Development of new diseases or resurgence of previous disorders
What is a characteristic of the first identified cases of a new disease?
They are often fatal or severe
What is often discovered as more becomes known about a disease?
Less severe (and even asymptomatic) cases
What is a consequence of global climate change on diseases?
It extends the range of some diseases or helps create others
What is a current concern in the field of epidemiology?
The threat of bioterrorism and newly emerging disease problems
What is the role of epidemiologists in providing hypotheses about disease causation?
To provide initial hypotheses about disease causation for other scientists to test
What is a challenge in the field of epidemiology?
The many newly emerging disease problems and the threat of bioterrorism
What is considered when setting disease control priorities?
The potential of a disease to spread, its likelihood of causing death and disability, and its cost
What was a major factor in allocating a larger proportion of national resources to the study and control of AIDS in the early 1980s?
The rapid increase in incidence over a brief period
What is the focus of clinical epidemiology?
Improving disease diagnosis, treatment, and prognosis
What has been achieved regarding AIDS in the 21st century?
A degree of control has been achieved through antiretroviral drugs
What was the cause of severe acute respiratory syndrome (SARS) that appeared in China in 2003?
An animal coronavirus traced to unusual food animals
What is considered when determining the best diagnostic tests?
The selection of the best diagnostic tests, the determination of the best cutoff points, and the development of strategies to use in screening for disease
What is the focus of epidemiologists in healthcare settings?
Improving clinical medicine
What is a primary goal of epidemiologists in health planning?
To determine present and future community health needs
What is the primary goal of epidemiologists in setting disease control priorities?
To allocate resources effectively
What is a use of epidemiologic methods in patient care?
To estimate the probable course and outcome of a disease
Why did support for syphilis control efforts decline in the United States in the 1950s?
Due to a sharp drop in reported syphilis rates
What is an area where epidemiologists are being called to testify?
All of the above
What is the term for the study and control of AIDS?
AIDS research
What is a way that epidemiologic methods can be used in health services research?
To evaluate medical care in health program evaluation
What is a component of epidemiology?
All of the above
What is a type of analysis used in epidemiology?
Risk estimation
What is a goal of epidemiologists?
To understand the occurrence, distribution, and determinants of diseases
What is an application of epidemiologic methods?
All of the above
What is a factor considered in epidemiology?
All of the above
What is a use of demographic projection techniques?
To estimate future service needs
What is the term used to describe the variation in the severity of a disease process?
Biologic spectrum of disease
In the diphtheria outbreak investigated by James F. Jekel, what was the ratio of symptomatic to asymptomatic cases?
1:4
Why is ongoing surveillance of vaccine side effects essential after a vaccine is introduced?
To detect rare adverse reactions
What was the problem with the Salk inactivated polio vaccine that led to an outbreak of vaccine-associated poliomyelitis in 1955?
The vaccine was contaminated with live virus
Why were measles outbreaks detected in 1971, 1977, and 1990 despite initial progress in vaccination?
The vaccine was given too early, before maternal antibodies had disappeared
What is the term for the study of the distribution and determinants of health-related events in a population?
Epidemiology
What is the purpose of surveillance in the context of immunization programs?
To monitor the disease pattern and severity
What was the outcome of the vaccine surveillance program in the case of the Salk inactivated polio vaccine?
The vaccine was found to contain live virus
What was the reason for the development of a smallpox response plan in the United States after 2001?
The risk of bioterrorism
What was the outcome of the surveillance of the small number of persons vaccinated against smallpox after 2000?
The vaccine was found to be associated with cardiomyopathy
Study Notes
Epidemiology Definition and Scope
- Epidemiology is the study of the distribution and determinants of health-related events, diseases, or health-related characteristics among populations.
- It is a scientific approach to understanding health and disease in populations.
Origins of Epidemiology
- Derived from Greek roots: epi (upon), demos (people), and logos (study or discussion)
- Originated in the 19th century as a response to the need to study and control infectious diseases
Levels of Disease Study
- Submolecular or molecular level (e.g., cell biology, genetics, biochemistry, immunology)
- Tissue or organ level (e.g., anatomic pathology)
- Level of individual patients (e.g., clinical medicine)
- Level of populations (e.g., epidemiology)
Types of Epidemiology
- Classical epidemiology: focuses on population-oriented studies of health problems, particularly infectious diseases
- Clinical epidemiology: focuses on patients in healthcare settings, aiming to improve prevention, detection, diagnosis, treatment, and care of illnesses
Etiology and Natural History of Disease
- Etiology: the study of the cause or origin of a disease
- Natural history of a disease: the progression of a disease in the absence of medical or public health intervention
- Stages of disease:
- Predisease stage: before disease process begins
- Latent stage: disease process has begun, but no symptoms yet
- Symptomatic stage: disease manifestations are evident
Host, Agent, Environment, and Vector (HAEV)
- Host: human who is susceptible to disease
- Agent: disease-causing factor (e.g., virus, bacteria)
- Environment: external factors that influence disease transmission (e.g., poor sanitation, crowding)
- Vector: intermediate host or transmitter of disease (e.g., mosquito, tick)
Risk Factors and Preventable Causes
- Risk factors: characteristics or exposures that increase the likelihood of developing a disease
- Preventable causes: factors that can be changed or eliminated to reduce disease occurrence
- BEINGS model: categories of preventable causes of disease
- Biologic and behavioral factors
- Environmental factors
- Immunologic factors
- Nutritional factors
- Genetic factors
- Services, social, and spiritual factors### Infectious Diseases
- Respiratory therapy equipment rinsed with water can become a reservoir for Legionella, causing hospital-acquired legionnaires' disease.
- Lyme disease, first reported in 1975, was found to be caused by the bacterium Borrelia burgdorferi, transmitted by Ixodes ticks.
Immunologic Factors
- Smallpox is the first infectious disease to be eradicated globally, due to vaccination conferring individual immunity and herd immunity.
- Herd immunity occurs when vaccination reduces the ability of immunized individuals to spread diseases, leading to reduced transmission.
- Immunodeficiency can be caused by genetic abnormalities, infections, vaccines, cancer chemotherapy, and long-term corticosteroid use.
Nutritional Factors
- Dietary variations were found to be the main factor in the differing rates of myocardial infarction (MI) between Japanese Americans in Hawaii and Japan.
- The Japanese diet, rich in fish, vegetables, and fruit, with smaller portions, was associated with lower rates of MI.
- Denis Burkitt's research showed that a high intake of dietary fiber may prevent diseases such as diabetes and hypertension.
- Cross-cultural studies revealed that many diseases common in the US are rare in tropical Africa, suggesting that diet and environmental factors contribute to these diseases.
Genetic Factors
- Genetic inheritance interacts with diet and environment to promote or protect against illnesses, including heart disease and cancer.
- Genetic epidemiology studies the distribution of normal and abnormal genes in a population and their interaction with environmental factors.
- Ongoing research examines the interaction of genes with environmental, nutritional, and behavioral factors, as well as pharmaceutical treatments.
Services, Social Factors, and Spiritual Factors
- Medical care services can be beneficial but also dangerous, with iatrogenic disease occurring when a disease is induced by treatment or diagnostic procedures.
- Adverse events occur in 2.9-3.7% of hospitalized patients, with 19% caused by medication errors and 14% by wound infections.
- Social and spiritual factors, such as personal beliefs, social support, and religious faith, have been found to influence health and disease.
- Studies have shown that social support from family, friendship networks, and membership in groups can improve health outcomes.
- Meditation, massage, and other spiritual practices have also been found to have positive effects on health and quality of life.
Epidemic Investigation and Disease Control
- Epidemiologists use surveillance and investigative methods to provide initial hypotheses about disease causation, which are then tested in the laboratory.
- These methods have suggested the probable type of agent and modes of transmission for diseases, often within months of their recognition as new or emergent diseases.
Biologic Spectrum of Disease
- The biologic spectrum of disease refers to the variation in the severity of a disease process, including asymptomatic and mild cases.
- The iceberg phenomenon illustrates this concept, where most cases remain unseen, below the surface, analogous to asymptomatic and mild cases of disease.
- Studying only symptomatic individuals may produce a misleading picture of the disease pattern and severity.
Surveillance of Community Health Interventions
- Surveillance is essential to ensure the continued safety and effectiveness of vaccines and other preventive measures.
- The importance of continued surveillance is illustrated in the case of immunization against poliomyelitis, where a vaccine-associated outbreak was detected and addressed through surveillance.
Setting Disease Control Priorities
- Disease control priorities should be based on the potential of a disease to spread, its likelihood of causing death and disability, and its cost to individuals, families, and the community.
- Funding for disease control efforts should be allocated based on these factors, rather than solely on the number of reported cases.
Improving Diagnosis, Treatment, and Prognosis of Clinical Disease
- Epidemiologic methods are used to improve clinical medicine, particularly in the diagnosis, therapy, and prognosis of disease.
- These methods are used to select the best diagnostic tests, determine the best cutoff points for tests, and develop strategies for screening for disease.
Improving Health Services Research
- Epidemiologic methods are used in planning and evaluating medical care, including determining present and future community health needs.
- These methods are also used to estimate the effects of medical care in health program evaluation and cost-benefit analysis.
Providing Expert Testimony in Courts of Law
- Epidemiologists are increasingly called on to testify regarding the state of knowledge about topics such as product hazards and environmental exposures.
- Epidemiologic data is used in lawsuits involving claims of damage from environmental exposures, occupational illness, medical liability, and product liability.
Learn about the definition, origin, and scope of epidemiology, a scientific study of disease distribution and occurrence in populations. Understand what epidemiology entails beyond the study of epidemics.
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