Epidemiology and social causation of diseases Flashcards
What is epidemiology?
Epidemiology is the study of the frequency, distribution and determinants of disease and risk of disease in populations.
What in particular are epidemiologists interested in?
Occurrence of disease categorized by time, place and person
What do epidemiologists do?
Look at
- Trends over time and determine eg if number of cases has increased/decreased over time and the possible cause
- They look and see if particular areas have higher frequencies of a disease than others or if people with specific characteristics are more likely to get a disease
- Identify risk factors
What is a risk factor?
An attribute or exposure (e.g. aspect of personal lifestyle, environmental exposure or inherited characteristic) that is associated with an increased risk of disease.
Examples of risk factors?
XS alcohol intake= risk of cirrhosis, hypertension
Radiation leaks= thyroid cancer
BRCA1 mutation= Breast cancer
Why is it important from an epidemiological perspective to identify, understand and characterize the relationship between exposure to a risk factor and subsequent risk of disease?
- It can provide the evidence for disease causation
- Important to quantify the potential exposure to risk factors in a population, in order to determine how best to mitigate exposure risk.
What 2 terms are used to describe disease occurrence?
Prevalence
Incidence
Incidence Rate?
The number of new cases of a particular disease, arising within a population, over a set period of time
Incidence rate Equation?
Number of persons exposed to risk of developing that disease during that period of time
Prevalence Rate?
Measures the number of cases that are already present in the population at, or a particular point in time, or over a predefined period of time.
Prevalence Rate Equation?
Number of persons at risk of having the disease at that specified time
How are both incidence and prevalence rate usually expressed?
Per 1000
What does incidence not tell you about?
Number of people living with disease
‘Current level of disease in population’
What essentially is prevalence?
A snapshot
It describes the number of people who are known to be living with the condition/illness at a certain point in time.
What does Demography study?
Populations and their:
- Size and density
- Growth
- Age distribution
- Fertility
- Mortality
- Migration
- Vital statistics
What is demography?
Study of populations
Why is it important to understand population dynamics?
In order to plan and deliver health and social care services to a population in a way that best serves the population’s needs.
What is population size dependent on?
Births, deaths and migration
Population size equation?
P2= P1 + births+ deaths+ net migration
P2 is size of population at a given time
(P1 is size of population at start of period)
What do population pyramids provide?
Summary of the age and sex composition of a country and captures information about current birth and death rate trends
What kind of pyramid would a LEDC have?
A spike- high birth and death rate, high infant mortality
What kind of population pyramid would a country have once conditions start improving?
A wedge- still a high birth rate but lower death rate due to better healthcare and sanitation- population size increases
Population pyramid for a MEDC?
Barrel- low birth and death rate, population static in size, population in equilibrium
Why are rates referred to and not numbers?
Both statistics are similar when considered per head of population.
Equation to calculate crude birth rate?
Total mid-year population
Crude death rate equation?
Total mid-year population
How are birth and death rates expressed?
Per 1000 people
Crude death rate?
Mortality rate for a whole population - does not take into account the composition of a population
Why is standardization used?
To enable comparison of rates across populations.
What do standardized rates of mortality permit?
Standardised rates of mortality permit comparisons of mortality between populations with different age profiles.
What else can standardization be applied to?
Incidence and Prevalence rates
Most common standardization methods?
Sex and age
Can either be direct or indirect
Indirect standardization?
A common set of age-specific rates is applied to the populations whose rates are to be standardized. It essentially compares the expected rate with the observed rate. The simplest and most useful form of indirect adjustment is the Standardised Mortality Ratio.
Direct Standardization?
A common age-structured population is used as standard e.g. that of the European Union.
Health inequalities?
Differences in health outcomes
What best summarized internal, external and physical well-being?
Dahlgren and Whitehead in 1992 using the determinants of health diagram
What to remember as a doctor?
The population dimension when caring for your patients
How social and cultural context can help to explain disease distribution
Importance of public health in achieving disease prevention
