Lecture 2 Flashcards
(20 cards)
Describe the goal of epidemiology
Epidemiology refers to the study of frequency of dis-ease within populations (this is the goal)
Disease frequency, occurence, risk, and distribution can all mean the same thing
What does epidemiology focus on/start with
Always starts with a population (rather than cell/organ)
Importantly, you should always start by counting the denominator/pop no. as to not confuse others with those in the denominator
What are the steps of all epidemiological studies?
We start by describing a population and splitting them into groups, and then counting them
Finally, we count the number of cases of dis-ease that occur within the groups (/population)
Why do we measure the frequency of disease in different populations/groups
Comparing the occurrence of dis-ease in different groups/populations (or of the same population at different times) provides insights into the causes, predictors, and the amount of dis-ease, and how to prevent, diagnose, and treat it
Describe population
Population typically refers to a number of individuals that share a common factor/feature (e.g. same ethnicity) – but can also be averages (e.g. average deaths from heart disease over 2000-2010) w
‘populations’ and ‘groups’ can essentially be used interchangeable - except on the GATE frame
Describe Exposure and Control groups
Populations can be split into further groups – e.g. exposed vs control groups
What do you do once you have set out the population and separated the groups?
After identifying and counting the population, the frequency of dis-ease is measured.
What is the definition of health
Epidemiological definition of health = absence of death, disease, or disability (narrow) OR the capacity to do what matters most to you (broad)
What is the definition of disease
Epidemiological definition of dis-ease = ‘dead, diseased or disabled’ or ‘not at ease’
Describe numerators
Numerator = no. with dis-ease (in groups)
Describe denominator
Denominator = population no. (within groups)
Where must the numerators come from
All within numerator (with disease) come from denominator (within the population)
How do you calculate disease frequency?
E (frequency of disease)
= N/D /T
What can disease frequencies be used for
If the frequency of dis-ease alters between two or more populations, this can assist in finding the causes of the dis-ease
What do you do once you have calculated the crude disease frequency
You have to ask whether you can compare populations as they are
What is the crude disease frequency
The disease frequency when you don’t adjust/standardise the population
What is age standardisation
Age standardisation is a process that epidemiologist use to account for confounding of age as to make a fairer and more meaningful comparison between populations with different ratios of ages
What is confounding?
Confounding refers to when an additional variable that is not being focused on/investigated impacts health outcomes and therefore quality of data
Give a key example for the important of age standardisation
Māori people have higher death rates from heart attack in each age group, but because the Māori population is younger, Pākehā have a higher overall heart attack death rate
What is the death rate in New Zealand
100% (1 per person per lifetime)
