week 2
What is the primary task of descriptive epidemiology?
Description epidemiology serves two primary purposes: assessing variations in disease occurrence in populations, as well as aiding in etiological hypotheses development.
Explain why cohort studies are an improvement over case-control studies with respect to measurement of exposure data.
17. Cohort studies are better than case-control studies because they classify subjects according to their exposure to a factor of interest and then observe them over time to document the occurrence of new cases (incidence) of disease or other health events. Cohort studies are a type of longitudinal design. Cohort studies allow epidemiologists to evaluate different outcomes but only a few expsoures.
Define the following term: Natural experiments
4. Natural experiments are defined as using naturally occurring situations/circumstances to test hypotheses. The circumstances are when groups within a population are exposed to different levels of the "hypothesized causal factor" (Friis, R.H., 2019) in an environment which closely mimics an experiment.
Define the following term: Prevalence
5. Prevalence refers to the number of existing cases of or deaths from a disease or health condition in a population at some designated time.
Define the following term: Incidence
6. Incidence is the number of new cases that develop in a population over a certain period of time.
Define the following term: Case fatality rate
7. Case fatality rate describes the number of deaths due to a disease within a specific amount of time divided by the total number of cases of the disease in the same amount of time. This value is then multiplied by 100. It is used to describe how lethal a disease is.
Define the following terms: Relative risk
9. Relative risk is defined as the ratio of the incidence rate of a disease or health outcome in an exposed group to the incidence rate of the disease or condition in a nonexposed group.
Explain the work of John Snow using the methodology of the natural experiment.
A natural experiment is a type of observational experimentation. According to the American Psychological Association in a natural experiment "... the researcher does not exert any influence over the situation but rather simply observes individuals and circumstances (APA, n.d.). When there was an outbreak of cholera in London, John Snow established that cases were most prevalent near the Broad Street Pump. He investigated by questioning residents and formulating a map of all the cases of cholera.
Define the following term: Descriptive epidemiology
Definition: Descriptive epidemiology is defined as epidemiological studies and activities with descriptive components that are much stronger than their analytic components or that fall within the descriptive area of the descriptive-analytic spectrum (Fris 2019).
Explain the difference between descriptive and analytic epidemiology. Give examples of how both types of study design are utilized in the field of environmental health.
Descriptive epidemiology regards the occurrence of disease among populations, by person, place, time, and other variables. An example of descriptive epidemiology in environmental health could be disease clustering, especially when looking at an abnormal aggregation of uncommon diseases like cancers in an area. Analytic epidemiology regards hypotheses about the association between possible exposures and conditions affecting health. These hypotheses are casual and exposure variables could include air pollution, carcinogens, and more. An example of analytic epidemiology in the field of environmental health is when researchers carry out natural experiments, using a naturally occurring event to test a hypothesis. This could be seen with John Snow discovering the cause of the cholera outbreak in London due to the singular pump on Broad Street.
Explain the reason why studies of the health effects of smoking among individuals who smoke would not be a concern of environmental epidemiology. Explain the reason why exposure to secondhand cigarette smoke is a concern of this discipline.
Environmental epidemiology mainly focuses on external health risks that affect all of those who live in a certain environment. Because the negative effects of smoking on the smoker themself is not due to a risk factor in the external environment this would not be a concern of environmental epidemiology. Smoking is a behavior one takes part in that directly causes negative health outcomes whereas exposure to secondhand smoke is not a behavior one takes part in. Secondhand smoke is the exposure to cigarette smoke within the external environment, therefor it directly connects to environmental epidemiology.
Define the following term: Epidemiology
Epidemiology is defined as the study of the distribution and determinants of health and diseases, morbidity, injuries, disability, and mortality in populations
Explain why epidemiology sometimes is called "population medicine." State how epidemiology contrasts with clinical medicine.
Epidemiology is sometimes called population medicine as it observes trends that naturally unfold in the population via assessment, and then seeks to treat them through preventative measures. Epidemiology commonly seeks to treat the population as a whole, and observes the occurrence of disease and negative health outcomes throughout the population whereas clinical medicine seeks to observe case-by-case occurrence and treat symptoms through tertiary prevention. Clinical medicine seeks curative means for negative health outcomes that have already unfolded on the individual scale, whereas "population medicine" seeks out prevention on a larger scale and to codify disease occurrence in order to predict trends and therefore preventatively treat them.
Explain why most studies conducted in the field of environmental epidemiology are nonexperimental.
Most studies conducted in the field of environmental epidemiology are non-experimental because they are based on observations and descriptions. The people involved in study have to be in their natural environment without any external interference because environmental epidemiology deals with myriad of factors that cannot be controlled for. These factors include diet, residence, genetics, cultural background, language, ethnicity, and social determinants of health.
Define the following term: Odds ratio
Odds Ratio (OR) is the measure of the association (relationship that is linear or nonlinear) between exposure and outcome used in case-control studies OR>1 means greater odds of association with exposure and outcome OR=1 means there is no association between exposure and outcome OR<1 means there is a lower odds of association between the exposure and outcome
Explain why Percival Potts was an important figure in Environmental and Occupational Health.
Percival Potts was the first person to describe an environmental cause of cancer. In 1775, Potts observed that chimney sweeps had high rates of scrotal cancer. He came to the conclusion that the high rates of cancer was due to the sweep's prolonged exposure to soot throughout their occupation.
Explain how federal level surveillance systems like the National Environmental Public Health Tracking Network generate their data.
Surveillence systems are important to increase efficnency and effectiveness of public health systems. A system as such impacts population health by generating information and capturing data that practitioners can utilize to improve the quality of decisions and actions. Surveillance systems use lab diagnostics to confirm health conditions, information technologies to understand surveillance processes of data collection, clinician consultation, public health consultations, and legislation to help gather more data. Federal Level surveillance systems such as the National Environmental Public Health Tracking Network generates data by using a network of systems and individuals to provide a set of health, exposure, and information summaries that allow scientists to draw insight from the data. Additionally, Data is generated and collected through reports transmitted to CDC from the 50 states. All data generated is analyzed to provide insight and create actionable tasks and decisions that can be worked on to improve well-being and public health of communities.
Define the following term: Environmental epidemiology
The term environmental epidemiology refers to the study of diseases and health conditions (occurring in the population) that are linked to environmental factors. The exposures, which most of the time are outside the control of the individual, usually may be considered involuntary and stem from ambient and occupational environments. Traditionally, environmental epidemiology has tended to focus on health effects linked to degradation of the air we breathe, the water we drink, and the food we eat. With the advances achieved, attention to chemical and physical impacts upon the environment has increased. Some of the agents and environmental factors being focused on are lead toxicity, particulates from diesel exhaust, and exposures to pesticides and halogenated compounds.
Hill's Criteria
describe the components of an observed relationship that increase the likelihood of causality in the relationship