Epidemiology: Measuring & Describing Disease 1 Flashcards
- Exposures and outcomes - Epidemiologic transition and populations - HIV
Define endemic
Diseases that reside within a population
Define epidemic
diseases that befall a population
Define epidemiology
the study of the distribution and determinants of health-related states/events in specified populations, and the application of this study to the control of health problems (how often diseases occur in different groups of people and WHY)
How does epidemiology relate to prevention
- Epidemiology is what enables us to prevent disease. - able to understand transmission, test interventions and control disease eg. John snow and cholera water pumps
List the 3 types of prevention
Primary, secondary and tertiary
Define primary intervention and relate it to an example
Primary: the prevention of disease through the control of exposure to risk factors. Eg. reducing salt in you diet reduces the risk of developing hypertension.
Define secondary intervention and relate it to an example
Secondary: the application of available measures to detect early departures from health and to introduce appropriate treatment and interventions. Eg. controlling hypertension with antihypertensive drugs to progression
Define tertiary intervention and relate it to an example
Tertiary: the application of measures to reduce or eliminate long-term impairments and disabilities, minimising suffering caused by existing departures from good health and to promote the patient’s adjustments to their condition. -Eg. Rehabilitation for someone who’s had a stroke so that they can return as close as possible to their pre-morbid activities.
Which type of prevention is for before the onset of disease
Primary prevention
Which type of prevention aims to slow progression of disease
Secondary Prevention
Which type of prevention enables return to functioning after insult of disease
Tertiary prevention
which types of prevention do the NHS currently focus more on? Which type of prevention would be best to focus on
- NHS focuses primarily on secondary and tertiary prevention - Focussing on Primary prevention would be a true health service
Which questions are important to ask during the study of epidemiology
What Why When How Where Who
Which answers are we looking for in epidemiology
Time Person Place
Describe Exposure and outcome in epidemiological terms. Use the example of the study of cancer.
An exposure in epidemiological terminology is essentially the variable that we are trying to associate with a change in health status. eg. in a study of cancer outcomes, we might look at Drug X (the exposure) and test its association on mortality at five-years (the outcome).
Describe the demographic transition model
- Looks at birth rate, death rate and total population.
- in the diagram, at stage 1, we have a high birthrate and a high death rate that broadly keep the total population in check, perhaps with a little bit of gradual increase over time.
- The death rate lowers and the birth rate maintains its trajectory at stage two, resulting in a large natural increase in the total population.
- eventually the birthrate begins to catch up with the reduction in death rate and the population begins to stabilise
Describe the epidemiological transition through this diagram
- progression of demographic transition .
- originally Omran in 1971 proposed 3 stages of the epidemiologic transition pestilence and famine, receding pandemics and degenerative and man-made diseases.
- In the late 1990s, a fourth stage was proposed - delayed degenerative diseases and emerging infections
Similar to the demographic transition, on diagram there is a birth rate, a death rate and a natural increase
Define the first stage of the epidemiological transition: Pestilence and famine
Period of Pre-Industrial Revolution in UK (up to 1800)
- Urbanisation
- Constraints on food supply
- High birth rate and high mortality.
- Life expectancy is low at birth.
What is life expectancy at birth
Life expectancy is a period of time at a specific age.
- the average length of time one can expect to live for based on everyone else in the population i.e average across entire population
Describe the second stage of the epidemiological transition: Recedeing pandemics
Receding Pandemics
Period of 1800s - 1950 in UK
- Agricultural development improves nutrition
- Water, sanitation, hygiene
- Vaccination emerges
- High birth rate and reducing mortality
- Life expectancy increasing
Describe the third stage of the epidemiological transition: Degenerative and manmade diseases
Degenerative and manmade diseases
Period of 1950 - 2010s in UK
- Lifestyle factors and non communicable diseases (NCDs) predominate: cancer and CVD
- Environmental and global determinants drive obesity and other risk factors
- Technology reduces need for physical labour (physical activity decreased)
- Addiction, violence and other issues emerge
Describe the fourth stage of epidemiological transition: Delayed degenerative and manmade diseases and emerging infections
Delayed degenerative and manmade diseases and emerging infections
Period of 2010s onwards
- Health technology defers morbidity, albeit at increasing financial cost
- Emerging zoonotic disease presents new threats (eg. COVID-19)
- Inequalities within and between countries come to the fore
Is every country/population at the same stage in the epidemiological transition?
No - countries can be at different stages of this progression, depending on the availability of healthcare, water, sanitation and hygiene.
Why is it important to understand population pyramids?
there are some diseases that affect young people, and other diseases that more commonly affect older people - the shape of your population is going to be an important thing to consider when planning your health system and predicting what needs are likely to arise.
Which shape is needed for a rapidly growing population?
A - As the infant mortality (in particular) decreases, the population will rapidly grow.
Which shape would best characterise the UK? Which factor plays into this
B - But Without immigration the UK would be demonstrating the C shape.
If you were advising the Italian government on their health system planning, which diseases do you think are going to cause most difficulty for their health system over the coming decade?
- Dementia
- Cancer
- Cardiovascular disease
What primarily accounts for the dip in life expectancy observed in 1918/19 worldwide
Pandemic H1N1 influenza
What is the correlation between life expectancy and income per capita worldwide between 1800-2020
As income per person (GDP/capita) increases, life expectancy generally increases
https://www.gapminder.org/tools/#$state$time$value=1800;;&chart-type=bubbles
What is the correlation over time between Child Mortality and Income per capita worldwide between 1800-2020
negative correlation - as income per capita increased, child mortality generally decreased
https://bit.ly/3u46wsh
Define exposure
the variable being tried to associate with a change in health status
• Can be a drug/behaviour/demographic characteristic etc.
Define outcome
The associated change in health status
Example: drug X (exposure) and test its association on mortality five years (the outcome)
What was the role of epidemiology in the history of HIV?
- Describing a consistent constellation of signs and symptoms
- Identifying the causative pathogen
- Inferring the mechanism(s) of transmission
- Determining the risk factors associated with disease transmission and prognosis
- Informing prevention strategies
- Evaluating the efficacy and effectiveness of therapies (including drugs and other interventions)
What is a case series study
a document comprising multiple case reports drawn together. The editorial note provides over-riding commentary.
Key points
Key points
- Epidemiology is the language of population health and central to applying the principles of evidence-based medicine. It gives you a language to precisely and scientifically describe relationships between exposures and outcomes
- Epidemiology poses and answers questions about the distribution of health and disease and seeks to explain these differences.
- Most epidemiology can be described in three dimensions time person and place.
- Demography is a closely related discipline to epidemiology: the epidemiology transition model demonstrates how populations, health and disease change over time.
- Prevention can be categorised into primary, secondary and tertiary
