CHLH 274 Midterm – Flashcards
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Where does the word epidemiology derive from?
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Epidemiology originates from the Greek words, epi (upon) + demos (people) + logy (study of).
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Definition of Epidemiology
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Epidemiology is concerned with the distribution and determinants of health and diseases, morbidity,injuries, disability, and mortality in populations.
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key aspects of the epidemiology definition
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Determinants Distribution Population Health phenomena Morbidity and mortality
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meaning of determinants
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Factors or events that are capable of bringing about a change in health.
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examples of determinants
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Biologic agents Bacteria Chemical agents carcinogens Less specific factors Stress Drinking sedentary lifestyle high-fat diet
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meaning of distribution
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Frequency of disease occurrence may vary from one population group to another.
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Examples of disease distribution
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Hypertension more common among young black men than among young white men. Coronary heart disease occurrence differs between Hispanics and non-Hispanics.
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meaning of population
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Epidemiology examines disease occurrence among population groups, not individuals. Epidemiology is often referred to as population medicine. The epidemiologic description indicates variation by age groups, time, geographic location, and other variables.
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meaning of health phenomena
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Epidemiology investigates many different kinds of health outcomes: Infectious diseases Chronic diseases Disability, injury Mortality Mental illness, suicide, drug addiction
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What does morbidity designate?
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designates illness
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What does mortality refer to?
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refers to deaths that occur in a population or other group
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What is the definition of an epidemic?
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"The occurrence in a community or region of cases of an illness (or an outbreak) clearly in excess of expectancy..." Relative to usual frequency of the disease.
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Number of cases indicating an epidemic vary according to
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Infectious agent Size and type of population Previous exposure or lack of exposure to the disease. Time and place of occurrence
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Three reasons to designate an infectious epidemic
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-A single case of a long absent communicable disease. -First invasion of a communicable disease. -Two cases of such a disease associated in time and place are sufficient evidence of transmission to be considered an epidemic.
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Are epidemics confined to infectious diseases
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no
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Define endemic
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Refers to disease that is habitually present in a particularly geographical region. An example is Malaria
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define pandemic
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" . . . an epidemic on a worldwide scale; during a pandemic, large numbers of persons may be affected and a disease may cross international borders." An example is a flu pandemic.
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Four aims of epidemiology
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To describe the health status of populations. To explain the etiology of disease. To predict the occurrence of disease. To control the occurrence of disease.
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Two goals of epidemiology
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First goal: Understand the natural history of disease and the factors that influence its distribution. Second goal: Intervention
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Foundations of Epidemiology
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Interdisciplinary Methods and procedures—quantification Use of special vocabulary Epidemic frequency of disease
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What is meant by epidemiology is interdisciplinary?
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-Biostatistics and the social and behavioral sciences -medically related fields of toxicology, pathology, virology, genetics, microbiology, and clinical medicine. -Causality of a particular disease in a population may involve the interaction of multiple factors -Disciplines helps unravel the factors associated with a particular disease.
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What is meant by epidemiology is quantification?
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-Quantification is a central activity of epidemiology. -Epidemiologic measures often require counting the number of cases of disease -Examines disease distributions are according to demographic variables such as age, sex, and race. -Quantification helps to investigate the sources of variation of disease by time, place and person.
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What are the two ascertainments of epidemics?
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Surveillance Epidemic threshold
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Define surveillance
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-The systematic collection of data pertaining to the; occurrence of specific diseases. -Analysis and interpretation of these data. -Dissemination of disease-related information. -To determine whether an epidemic is taking place.
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Define active surveillance vs passive surveillance
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x
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Define epidemic threshold
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The minimum number of cases (or deaths) that would support the conclusion than an epidemic was underway.
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With whom did epidemiology begin and what was disease attributed to?
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Epidemiology begun with the Greeks. Attributed disease causality to environmental factors.
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What were some early casual explanations for epidemics?
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Wrath of God Breakdown of religious beliefs and morality Influence of the weather "bad air"
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Who started a shift in causality of disease and what did he suggest?
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Hippocrates Disease might be associated with the physical environment. Shift from supernatural explanations of disease causation.
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What are some facts on the Black Death
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-Occurred between 1346-1352 -Pandemic (Europe, Northern Africa, Middle East) -Claimed one-quarter to one-third of population of Europe. -Plague was transmitted when fleas that feed on rodents bite a human host. -Caused painful swellings, high fever -Black splotches on the skin.
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Who was John Graunt?
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He was the first to use quantitative methods to describe population vital statistics. Showed excess male over female differences in mortality.
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Who was Edward Jenner?
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development of the smallpox vaccination.
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What is a natural experiment?
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The epidemiologist does not manipulate a risk factor but rather observes the changes in an outcome as the result of a naturally occurring situation.
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Who historically used a natural experiment?
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John Snow investigated a cholera outbreak that occurred during the mid-19th century in Broad Street, Golden Square, London.
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What did Snow find?
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-Linked the cholera epidemic to contaminated water supplies. -Two different water companies supplied water from the Thames River to houses in the same area. -The Lambeth Company moved its source of water to a less polluted portion of the river. -Snow noted that during the next cholera outbreak those served by the Lambeth Company had fewer cases of cholera
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What would contemporary natural experiments consist of?
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Currently, natural experiments may be the result of legislation, policy changes or environmental interventions.
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Name some examples of contemporary natural experiments.
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Seat Belt Law--Did seat belt use reduce fatalities from motor vehicle accidents? Tobacco Tax--Did the increase in cigarette price decrease the sale of cigarettes? Helmet Law--Did requiring the use of helmets by motorcyclists reduce the number of head injuries sustained?
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Who was Robert Koch?
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-In late 1800s, Robert Koch verified that a human disease was caused by a specific living organism. -Led to the classification of disease by specific causal organisms.
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What were Koch's four postulates?
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-Microorganism must be observed in every case of the disease. -Microorganism must be isolated and grown in pure culture. -Pure culture must, when inoculated into a susceptible animal, reproduce the disease. -Microorganism must be observed in, and recovered from, the experimental diseased animal.
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Name some recent applications of epidemiology
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Framingham Heart Study (since 1948) investigates coronary heart disease risk factors. Smoking and lung cancer AIDS, breast cancer screening, secondhand smoke.
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What are five applications of epidemiology?
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Infectious diseases Environmental health Chronic diseases, Lifestyle and health promotion Psychiatric and social epidemiology Molecular and genetic epidemiology
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What are the seven uses of epidemiology?
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-To study the history of the health of populations (e.g. rise and fall of diseases, changes in their characteristics, useful projections into the future) -To diagnose the health of the community (e.g. distribution of illness, to identify groups needing special attention) -To study the working of health services (e.g. for improvement) -To estimate from the group, the individual risks of disease and chances of avoiding them. -To identify syndromes -To complete the clinical picture of chronic diseases and describe their natural history (e.g. for prevention and control) -To search for causes of health and disease (e.g. mode of transmission, risk factors)
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What are secular trends?
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changes in disease frequency over time
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What are the 3 leading causes of death in the US?
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heart disease, cancer, and stroke
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What are factors affecting reliability of observed changes in diseases over time? (seven)
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-Altered diagnostic criteria (e.g. new knowledge about disease, older criteria omitted) -Aging of the general population -Reduced impact of infectious diseases -Improved medical care -Decline in death rate -Uncertainty about the precise cause of death -Changes in the fatal course of the condition/reduction in death from the disease.
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What are the four disorder trends?
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Disappearing Residual Persisting New epidemic
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What is meant by a disappearing disorder and give some examples.
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Formerly common sources of morbidity and mortality in developed countries. But are no longer present in epidemic form. Eg. Small pox, Poliomyelitis
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Why are disappearing disorders disappearing? (three reasons)
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Diseases have been brought under control due to: Immunizations Improvement in sanitary conditions Use of antibiotics and other medications
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What is a residual disorder and give some examples.
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Key contributing factors to the disease are largely known. BUT specific methods of control have not been effectively implemented. Eg. STD, infant mortality, alcohol abuse, tobacco use.
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What is a persisting disorder and give some examples.
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Diseases that remain common Unknown method of prevention and cure Eg. Some forms of cancer and mental disorder
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What is meant by a new epidemic disorder and give some examples.
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Diseases that are increasing markedly in frequency in comparison with previous time periods. Eg. Lung cancer, AIDS
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Why are there new epidemic disorders? (four reasons)
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The emergence of new epidemics of disease may be due to: -Increased life expectancy of the population -New environmental exposure -Changes in lifestyle diet -Other practices associated with contemporary life. Eg. Obesity and type 2 Diabetes.
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Define population dynamics
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A population dynamics represents the age and sex composition of the population of an area or Country at a point in time.
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Why is it useful to examine the distribution of a population by age and sex (i.e. population dynamics)?
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Impact of acute conditions Quality of medical care available to the population.
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What percent of the population in the US will be over 65 in 2030?
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About 20% of the U.S. population in 2030 will be age 65 and older.
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What are 3 factors that affect the size of populations?
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Three factors that affect the size of populations are births, deaths, and migration.
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How do you describe a population with no net increases or decreases?
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the population is in equilibrium
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define fixed population
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adds no new members and, as a result, decreases in size due to deaths only
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define dynamic population
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adds new members through migration and births or loses members through emigration and deaths
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define steady population
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A population is in steady state when the number of members exiting equals the number entering
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What do you see in birth/death rates across time in developed countries and what is this trend termed?
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Historical shift from high birth and death rates to lower birth and death rates found in developed countries. It is called demographic transition.
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What are reasons for the decline in death rates (2) and the decline of birth rates (1)
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Decline in death rates attributed to: Improvement in general hygiene Social conditions Decline of birth rates attributed to: Industrialization and urbanization
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What is meant by epidemiologic transition?
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Describes the shift in the pattern of morbidity and mortality from infectious and communicable diseases to chronic, degenerative diseases.
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How can epidemiology be used as a descriptive tool in terms of older vs. younger communities?
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Age and sex and typical health conditions Older community - health problems related to aging Younger community immunizations STD's prevention injuries and accidents
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Epidemiology as a Descriptive tool does what?
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Provides a key to the types of problems requiring attention.
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Epidemiology in policy evaluation accomplishes what?
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Determines the need for specific health services -Epidemiologic evidence receives considerations at national and global levels -Influences individuals decision concerning lifestyle, work and family.
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What are four examples of epidemiology in policy evaluation?
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Fluoridation of water Helmet protection for motorcycle riders Mandatory seat belt use in motor vehicles Air bags in vehicles
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What is meant by policy cycle
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Examination of population health Assessment of potential intervention Alternative policy choices Policy implementation Policy evaluation
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What is operations research (OR)?
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The study of the placement and optimum utilization of health services in a community.
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Give some examples of using epidemiology for operations research?
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Health services that are not being supplied. Underserved population Characteristics that affect service delivery - Community -Providers -Patients
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What is meant by program evaluation?
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Uses epidemiologic tools to determine how well a health program meets certain stated goals.
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What are some examples of using epidemiology for program evaluation?
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Methods for selecting target populations Data analysis techniques Research designs Assessment of health care needs Extent to which program reaches: Minority individuals Social and economically disadvantaged persons The aged Target population
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What is meant by the statement "Henle-Koch postulates not relevant to many contemporary diseases"
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Agent present in every case of the disease. CVD? One agent-one disease CVD? Cigarette smoking? Diseases of noninfectious origin?
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What is the widely accepted cause for chronic diseases?
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It is now widely accepted that there is no single causal agent but rather multiple factors that produce chronic diseases.
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What is a risk factor?
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exposure that is associated with a disease
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What are the 3 criteria for risk factors?
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-The frequency of the disease varies by category or value of the factor. e.g., light smokers vs. heavy smokers, non smokers vs. light smokers -The risk factor precedes onset of the disease. -The observed association must not be due to error. (e.g. in selection of study group, in measurement of exposure and disease, or in the analysis)
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Five criteria for causality
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Strength of association Time sequence Consistency upon repetition Specificity Coherence of explanation
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What did Hill expand the list of criteria for causality to include?
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Biologic gradient Plausibility Experiment Analogy
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What is meant by strength of association?
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Strong association less likely to be due to error
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What is meant by consistency upon repetition?
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Association observed by different persons in different places, circumstances, and time
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What does the criteria specificity mean in the context of causality?
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Study factor is associated with only one disease Used as evidence in favor of causality, not as refutation against it. Since many factors have multiple effects and most diseases have multiple causes.
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What is meant by time sequence in the context of causality?
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The shorter the duration between exposure to an agent and development of the disease (latency period) the more certain the causation.
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What is meant by biologic gradient in the context of causality?
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Dose-response -an increase in disease risk with an increase in disease exposure.
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What is meant by biological plausibility in the context of causality?
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Hypothesized effect makes sense in the context of current biological knowledge
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What is meant by coherence of explanation in the context of causality?
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The association must not conflict with what is already known about the natural history and biology of the disease
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Define case/control study
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A type of design that compares persons who have a disease (cases) with those who are free from the disease (controls).
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What is a cohort and what do you do with one?
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A group of people free from a disease is assembled according to a variety of exposures. The group (cohort) is followed over a period of time for development of disease.
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What determines a study's influence? (three)
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Criteria of causality Relevance to each patient (Size of the risk) Public health implications (Individual vs. population)
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What does the natural history of disease refer to?
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The natural history of disease refers to the course of disease from its beginning to its final clinical end points.
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What is pre-pathogenisis?
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before agent reacts with host
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What is pathogenesis and what is it marked by?
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Pathogenesis--after agent reacts with host. Marked by the initial appearance of the disease (presymptomatic stage)
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What are later stages in the context of the natural history of disease?
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Later stages include development of active signs and symptoms.
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What are the possible clinical end points?
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recovery, disability, or death.
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When does primary prevention occur and what does it include?
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Occurs during prepathogenesis phase. Includes health promotion and specific protection against diseases.
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What is Primordial Prevention?
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Actions or measures that inhibit conditions known to increase the risk of disease.
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Compare primordial prevention and primary prevention.
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Primordial prevention is concerned with minimizing health hazards in general and inhibiting the emergence of risk factors (i.e. targeting children for obesity, smoking, etc.). Primary prevention seeks to lower the occurrence of disease.
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Compare active vs. passive primary prevention.
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Active Necessitates behavior change on the part of the subject. Examples: Vaccinations and wearing protective devices. Passive Does not require any behavior change. Examples: Fluoridation of public water and vitamin fortifications of milk and bread products.
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When does secondary prevention occur and what does it include?
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Occurs during pathogenesis phase. Designed to reduce the progress of disease. Early diagnosis, prompt treatment and disability limitations. Examples are screening programs for cancer
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What is tertiary prevention and when does it occur?
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Takes place during late pathogenesis Disease has already occurred, treated clinically but rehabilitation needed. Examples include: physical therapy for stroke patients
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Define count
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The simplest and most frequently performed quantitative measure in epidemiology. Refers to the number of cases of a disease or other health phenomenon being studied.
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What is a ratio?
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Defined as the value obtained by dividing one quantity by another.
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Are proportions, rates, and percentages ratios?
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Proportions, rates, and percentages are also ratios.
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What is a proportion and what is it important to know when finding one?
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A type of ratio in which the numerator is part of the denominator. Proportion is a measure that states a count relative to the size of the group. It is important to know the size of the denominator.
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What is a rate?
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a ratio that consists of a numerator and a denominator and in which time forms part of the denominator;the numerator consists of the frequency of a disease over a specified period of time and the denominator is a unit size of the population.
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How are rates different than proportions?
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The denominator for rates involves a measure of time
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What are the 3 elements of rates?
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disease frequency unit size of population time period during which an event occurs
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What is a reference population?
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The reference population is the population from which cases of a disease have been taken from.
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Crude death rate
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Number of deaths in a given year/ Reference population (during the midpoint of the year)
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Define prevalence
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The number of existing cases of a disease or health condition in a population at some designated time
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Three reasons for using prevalence?
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Describing the burden of a health problem in a population. Estimating the frequency of an exposure. Determining allocation of health resources such as facilities and personnel.
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period prevalence
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The total number of cases of a disease that exist during a specified period of time. It could be a week, month, or longer time interval.
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How do you calculate a period prevalence?
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To determine the period prevalence Combine the number of existing cases at the beginning of the time interval with the new cases that occur during the interval
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In the waterfall analogy what represents the prevalence?
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water collecting in the pool at the base symbolizes prevalence
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Define incidence
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The number of new cases of a disease that occur in a group during a certain time period
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In the waterfall analogy what represents incidence?
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The water flowing down the waterfall symbolizes incidence
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Three elements of incidence rate (Cumulative Incidence)
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Numerator = the number of new cases. Denominator = the population at risk. Time = the period during which the cases occur.
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What is excluded from an incidence rate?
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Individuals who have a history of the disease are not included.
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Who is excluded from a population at risk?
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Individuals who already have the disease are excluded Individuals who are also not capable of developing the disease are also excluded
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Who do you include in a population at risk?
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Those exposed to disease agent Unimmunized May consist of the entire population
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What is an attack rate and what is it used for?
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Alternative form of incidence rate. Used for diseases observed in a population for a short time period. Often as a result of specific exposure.
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Attack rate formula
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Ill/ Ill + Well X 100 (during a time period)
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What is cumulative incidence?
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Is the proportion of a fixed population that become diseased during a stated period
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What is incidence density?
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An incidence measure used when members of a population or study group are under observation for different lengths of time. Different length of time due to; - death, drop out, migration etc.
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How do you get person-years for incidence density?
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Person-years are derived by: - Summing up the product of each category of length of observation and the number of subjects in the category.
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Incidence density formula
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Number of new cases during the time period/Total person-time of observation
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What is the interrelationship between prevalence and incidence?
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The prevalence (P) of a disease is proportional to the incidence rate (I) times the duration (D) of a disease. Interrelationship : P = ID
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If duration of disease is short and incidence is high...
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prevalence becomes similar to incidence Short duration--cases recover rapidly or are fatal Eliminating the build up of prevalent cases Example: common cold
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If duration of disease is long and incidence is low...
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prevalence increases greatly relative to incidence. Example: many chronic diseases
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Prevalence vs incidence in the context of gay men and AIDS
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The number of annual incident cases of AIDS in gay men decreased in the US from the midd-1980s to the late 1990s. Due to Recent anti-retroviral treatment Prevention strategies for reducing high risk sexual behavior In contrast, the annual prevalent cases of AIDS in gay men has greatly increased in the US during the same period Due to Recent treatment approaches for AIDS has been successful in prolonging life of persons.
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general fertility rate
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# of live births within a year/# of women aged 15-44 years during the midpoint of the year
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Infant mortality rate
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number of infant deaths among infants aged 0-365 days during the year/number of live births during the year
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What is the time frame for fetal death rate?
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number of fetal deaths after 20 weeks or more gestation over number of live births plus number of fetal deaths after 20 weeks or more gestation
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What is the time frame for late fetal death rate?
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number of fetal deaths after 28 weeks or more gestation over number of live births plus number of fetal deaths after 28 weeks or more gestation
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fetal death ratio
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number of fetal deaths after 20 weeks or more gestation over number of live births
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neonatal mortality rate
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# of infant deaths under 28 days of age over # of live births
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What three things does neonatal mortality rate reflect?
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congenital malformations prematurity (birth before gestation week 28) low birth weight (birth weight less than 2,500 g)
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postneonatal mortality rate
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# of infant deaths from 28-365 days after birth over # of live births - neonatal deaths
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What does post-neonatal mortality rate reflect?
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Reflects environmental events, control of infectious diseases, and improvement in nutrition.
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What is perinatal mortality rate and what does it reflect?
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It combines mortality during the prenatal and postnatal periods. Reflects environmental events that occur during pregnancy and after birth. Number of late fetal deaths after 28 weeks or more gestation plus infant deaths within 7 days of birth over # of live births plus # of late fetal deaths
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perinatal morality ratio
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Number of late fetal deaths after 28 weeks or more gestation plus infant deaths within 7 days of birth over Number of live births
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What do maternal mortality rates reflect?
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Reflects health care access and socioeconomic factors It includes maternal deaths resulting from causes associated with pregnancy and puerperium (during and after childbirth).
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What do specific rates refer to?
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Specific rates refer to a particular subgroup of the population defined in terms of race, age, sex, or single cause of death or illness.
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What is Proportional Mortality Ratio (PMR)?
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Mortality due to a specific cause during a time period over Mortality due to all causes during the same time period and multiplied by 100 to get a percentage
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Define adjusted rates
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Summary measures of the rate of morbidity and mortality in a population in which statistical procedures have been applied to remove the effect of differences in composition of various populations.
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What are the two methods of adjusted rates?
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Direct method Indirect method
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What is the direct method for adjusting rates?
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Direct method may be used if age-specific death rates in a population to be standardized are known and a suitable standard population is available. By standardizing the observed rates of disease in the population, one is assured that: Any observed difference that remain are not due to factors such as -age -race -sex
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What is the indirect method for adjusting rates?
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Indirect method may be used if age-specific death rates of the population for standardization are unknown or unstable. The standardized mortality ratio (SMR) can be used to evaluate the results of the indirect method. Indirect method of standardization does not require: Knowledge of the actual age specific incidence OR Mortality rate among each group.
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What is standardized mortality ratio (SMR)?
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observed deaths over expected deaths and multiplied by 100
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What does a SMR of 1 mean, of 2?
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If the observed and expected numbers are the same, the SMR would be 1.0, indicating that observed mortality is not unusual. An SMR of 2.0 means that the death rate in the study population is two times greater than expected.
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Examples of the characteristic person
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Who is being affected Young versus Old Males versus females Rich versus poor More educated versus less educated
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Examples of the characteristic place
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Where is the problem occurring? Urban versus rural Some states more than other states Only in a particular state National versus International Plentiful rainfall or little rainfall Polluted versus Unpolluted areas
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Examples of the characteristic time
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When is the problem occurring? Winter versus Summer Sudden increase over a short period Problem increasing over long periods of time.
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What three characteristics are central to epidemiology?
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person, place, and time
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descriptive epidemiology
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Descriptive Epidemiology is concerned with characterizing the amount and distribution of disease within a population.
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Analytic epidemiology
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Analytic Epidemiology is concerned with the determinant of disease. The reason for; Relatively high or low frequency of disease in specific population subgroups
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Three objectives for descriptive epidemiology
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To evaluate and compare trends in health and disease among countries or subgroups within countries. To provide a basis for planning, provision, and evaluation of health services. To identify problems for analytic studies
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Person characteristic age
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One of the most important factors to consider when describing the occurrence of any disease or illness. Public health professionals often use age-specific rates when comparing the disease burden among populations
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Trends in age group
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During 2003, Accident was the leading cause of the death (1-44) years Chronic diseases (heart disease and cancer) were in the leading killers (45 and older)
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Trends in childhood disease
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The major cause of death developmental problems, e.g., congenital birth defects Infectious and communicable diseases such as measles, mumps, chicken pox and meningococcal disease
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Trends in teenage years disease
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Accidents, violence, and suicide Unplanned pregnancy, substance abuse Excessive screen time may lead to Obesity (risk factor for chronic diseases).
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Trends in adult disease
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20 to 34 years, accidental injury is the leading cause of death. The remaining six major cause of death are homicide, suicide, cancer heart diseases and HIV
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Trends in older adult disease
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Chronic diseases such as heart disease and cancer become the dominant source of morbidity and mortality after age 45.
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What is meant by validity of diagnosis?
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Age-specific incidence rates among elderly often inaccurate. Inaccuracies may result from the difficulty in fixing the exact cause of death among older individuals.
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What is meant by multimodality?
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Age-specific distributions can be linear (e.g., cancer), or multimodal (e.g., tuberculosis).
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What is meant by latency effects?
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Age effects on mortality may reflect the long latency period between environmental exposures and subsequent development of disease. Exposure to a potential carcinogen and development of cancer at a much later life.
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What is the biologic clock phenomenon?
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Refers to an endogenous process associated with increased vulnerability to disease. Conditions that occur in the aged that are believed to have genetic basis. Example: Alzheimer's disease.
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What is the difference in disease for genders?
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Males generally have higher all-cause age-specific morality rates than females from birth to age 85 and older. Men often develop severe forms of chronic disease. Generally, death rates for both sexes are declining. Reports from the 1970s indicated female age-standardized morbidity rates for many acute and chronic conditions were higher than rates for males, even though mortality was higher among males.
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What is the leading cause of mortality among women?
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Coronary heart disease (CHD) is the leading cause of mortality among women. Women may not be alert for symptoms of CHD and seek needed treatment.
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What is the impact of disease on minority women?
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Minority women face a higher burden of morbidity from chronic diseases than men.
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What is the relationship between marital status and disease?
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-In general, married people tend to have lower rates of morbidity and mortality than those who are single. -Among older women, divorce and separation are associated with adverse health outcome. -Never married adults (especially men) less likely to be overweight
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What is meant by marriage being protective and selective?
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Protective: may provide an environment conducive to health. Selective: People who marry may be healthier to begin with.
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Name two reasons why African Americans might have higher blood pressure levels?
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Higher blood pressure levels Possible influence of stress or diet. Higher rates of hypertensive heart disease.
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In 2003 how much greater was the death rate in African Americans compared to whites?
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In 2003, age-adjusted death rate for African Americans was 1.3 times rate for whites.
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In comparison with 4 other racial/ethnic groups, African American women have the highest age-adjusted rate of what?
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In comparison with 4 other racial/ethnic groups, African Americans have the highest age-adjusted female breast cancer death rate.
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Why might breast cancer rates be so high in African American women?
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Differences in access to and quality of mammography services Access to treatment of breast cancer
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What do American Indian adults have high rates of?
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American Indian adults have high rates of; chronic diseases Adverse birth outcome Infectious diseases (TB and Hepatitis A) in comparison with the general US population
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For Pima Indians how much greater is the death rate for males aged 25-34?
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For Pima Indians: For males ages 25 to 34, the death rate is 6.6 times that for all races in U.S.
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Overall what do Japanese demonstrate lower rates of? Why might that be?
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Japanese demonstrated lower mortality rates. Lower rates of CHD and cancer. Low CHD rates attributed to low-fat diet and institutionalized stress-reducing strategies.
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Define acculturation
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Defined as modifications that individuals or groups undergo when they come in contact with another country.
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What does acculturation provide evidence of?
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Provide evidence of the influence of environmental and behavioral factors on chronic disease.
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In what group are TB rates highest?
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TB rates highest among Asian/Pacific Islander group.
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What do some Asian groups show high rates of?
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Some Asian groups have high rates of smoking when compared to the general U.S population. e.g., Cambodian Americans.
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What does the Hispanic Health and Nutrition Examination Survey (HHANES) look at?
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Examined health and nutrition status of major Hispanic/Latino populations in the U.S.
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Mexican Americans have low rates of _____ but high rates of_____.
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Low rate of CHD among Mexican Americans. Diet & Social support San Antonio Heart Study Found high rates of obesity and diabetes among Mexican Americans.
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What is nativity and what are the categories for it?
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Place of origin of the individual or his or her relatives. Categories are foreign born or native born
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How are nativity and migration related?
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Nativity and migration are related. Foreign-born persons had immigrated to their host countries
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What are programmatic needs resulting from migration?
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Specialized screening programs (tuberculosis and nutrition). Familiarization with formerly uncommon (in U.S.) tropical diseases.
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What is the Healthy Migrant Effect and what influence does it have on epidemiological studies?
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Observation that healthier, younger persons usually form the majority of migrants. Often difficult to separate environmental influences in the host country from selective factors operative among those who choose to migrate.
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What activities do Seventh Day Adventists and Mormons participate in that affect their rates of morbidity and mortality?
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Follow vegetarian diet and abstain from alcohol and tobacco use. Have lower rates of CHD, reduced cancer risk, and lower blood pressure.
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What is low social class related to?
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Low social class is related to excess mortality, morbidity, and disability rates.
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What are some reasons low social classes have worse health?
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Factors include: Poor housing Crowded conditions Racial disadvantage Low income Poor education Unemployment Exposure to environmental and work related hazards Both material and social deprivation Lack of access to health care Negative lifestyle
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How is social class measured?
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Prestige of occupation or social position Educational attainment Income Combined indices of two or more of the above variables
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Where is the highest incidence of severe mental illness in the US?
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In the U.S., the highest incidence of severe mental illness occurs among the lowest social classes.
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Mental Health and Social Class-What are the two hypotheses
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Social causation explanation (breeder hypothesis)—conditions associated with lower social class produce mental illness. Downward drift hypothesis—Persons with severe mental disorders move to impoverished areas.
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What are some correlates between health and low social class?
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Higher rate of infectious disease. Higher infant mortality rate and overall mortality rates. Lower life expectancy. Larger proportion of cancers with poor prognosis. May be due to delay in seeking health care.
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What are the types of place comparisons?
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International Geographic (within-country) variations Urban/rural differences Localized occurrence of disease
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What is one role of WHO and what does their findings show?
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World Health Organization (WHO) tracks international variations in rates of disease. Infectious and chronic diseases show great variation across countries.
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Why is disease frequency different among countries?
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Variations are attributable to climate, cultural factors, dietary habits, and health care access.
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Of 37 countries how does male and female life expectancy compare?
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Of 37 countries, the U.S. was 26th in male life expectancy and 25th in female life expectancy.
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What is the trend in CHD, Hypertension, stroke, and diabetes between developed and developing countries?
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CHD, Hypertension, stroke, and diabetes were formerly confined to developed countries, but now its occurring more frequently in developing Countries as living standards improve
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What % does infectious disease account for in developed vs less developed countries?
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Infectious diseases account for fewer than 5% of all death in developed countries but 50% of death in less developed countries.
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Why do you see variations in disease within a country?
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Due to variations in climate, geology, latitude, pollution, and ethnic and racial concentrations.
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What are urban diseases and mortality associated with?
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Urban diseases and mortality are associated with crowding, pollution, and poverty.
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Why are there differences in disease patterns within localized places?
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Disease patterns are due to unique environmental or social conditions found in particular area of interest. Examples include: Goiter: iodine deficiency formerly found in land-locked areas of U.S.
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What are the reasons for place variation in disease?
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Gene/environment interaction Influence of climate Environmental factors Example: chemical agents linked to cancer
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First: What are the characteristics of time? Explain the meaning of cyclic fluctuations?
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Characteristics of time: Cyclic fluctuations, Point epidemics, Secular time trends, Clustering (Temporal and Spatial) Periodic changes in the frequency of diseases and health conditions over time. Related to changes in lifestyle of the host, seasonal climatic changes, and virulence of the infectious agent. Examples: higher heart disease mortality in winter; more accidents in summer.
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Explain point epidemic
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The response of a group of people circumscribed in place and time to a common source of infection, contamination, or other etiologic factor to which they were exposed almost simultaneously. Examples: foodborne illness; responses to toxic substances; infectious diseases.
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Explain secular time trends
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Refer to gradual changes in the frequency of a disease over long time periods. Example is the decline of heart disease mortality in the U.S. May reflect impact of public health programs, dietary improvements, better treatment, or unknown factors.
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case clustering
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refers to an unusual aggregation of health events grouped together in space and time
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temporal vs. spatial clustering
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Temporal clustering: e.g., post-vaccination reactions Spatial clustering: concentration of disease in a specific geographic area.
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temporality
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refers to the timing of information about cause and effect Did the information about cause and effect refer to the same point in time? Or, was the information about the cause garnered before or after the information about the effect? Demonstrating temporality is a difficulty of most observational studies.
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What are the pros and cons of Cross-sectional and case-control study designs?
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Advantage: Efficient for generating and testing hypotheses. Disadvantage: Leads to challenges regarding interpretation of results.
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What is a specific limitation of a cross-sectional study?
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Cross-sectional studies: Present difficulties in distinguishing the exposures from the outcomes of the disease, especially if the outcome marker is a biological or physiological parameter.
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What is a specific limitation of a case-control study?
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Case-control studies: Raise concerns that recall of past exposures differs between cases and controls.
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What is a cohort?
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defined as a population group, or subset thereof, that is followed over a period of time The term cohort is said to originate from the Latin cohors, which referred to one of ten divisions of an ancient Roman legion. Cohort group members experience a common exposure associated with a specific setting (e.g., an occupational cohort or a school cohort) OR Cohort group members share a non-specific exposure associated with a general classification (e.g., a birth cohort—being born in the same year or era)
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What is meant by cohort analysis?
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The tabulation and analysis of morbidity or mortality rates in relationship to the ages of a specific group of people (cohort) identified at a particular period of time and followed as they pass through different ages during part or all of their life span.
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What did Wade Hampton Frost do?
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Popularized cohort analysis method. Arranged tuberculosis mortality rates in a table with age on one axis and year of death on the other. One can quickly see the age-specific mortality for each of the available years on one axis and the time trend for each age group on the other.
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What is a life table?
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Give estimates for survival during time intervals and present the cumulative survival probability at the end of the interval. Enables us to project the future life expectancy of persons born during the year as well as the remaining life expectancy of persons who have attained a certain age. Example: Life tables can be constructed to portray the survival times of patients in clinical trials
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What are the two life table methods?
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There are two life table methods: Cohort Life Table Period (Current) Life Table
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What is a cohort life table?
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Cohort life table: Shows the mortality experience of all persons born during a particular year. Example 1900
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What is a period life table?
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Period life table: Gives an overview of the present mortality experience of a population and shows projections of future mortality experience.
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life expectancy
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refers to the number of years that a person is expected to live, at any particular year
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Years of potential life lost (YPLL)
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Computed for each individual in a population by subtracting that person's life span from the average life expectancy of the population. Assume the average person lives until age 65. If an individual dies at age 60 then that person has lost 5 years of life
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Disability-adjusted life years (DALYs)
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Adds the time a person has a disability to the time lost to early death.
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Explain a cohort study method.
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Start with a group of subjects who lack a positive history of the outcome of interest and are at risk for the outcome. Include at least two observation points: one to determine exposure status and eligibility and a second (or more) to determine the number of incident cases. Permit the calculation of incidence rates. Can be thought of as going from cause to effect. Involve the collection of primary data. Individual forms the unit of observation
