L1-2 Introduction to Epidemiology Flashcards
What is epidemiology?
The study of patterns, causes & effects of health & disease in defined populations.
Name the 2 types of error?
- Random error
- Systematic error
Define Random Error.
An error in measurement caused by factors which vary from one measurement to another. Has a zero-mean.
Define Systematic Error.
What can it be divided into?
An error having a non-zero mean, so that its effect is not reduced when observations are averaged.
- Selection bias
- Information bias
Name the 4 epidemiological study designs.
Case-control studies
Cohort studies
Cross-sectional studies
Ecological studies
What is genetic epidemiology?
The study of role of genetic factors in determining health & disease in families & populations.
Name the genetic epidemiological study design type:
“Is there a genetic component to the disease & what are the relative contributions of genes & environment?”
Familial aggregation studies.
Name the genetic epidemiological study design type:
“What is the pattern of inheritance of the disease (dominant or recessive)?”
Segregation studies.
Name the genetic epidemiological study design type:
“On which part of which chromosome is the disease gene located?”
Linkage studies.
Name the genetic epidemiological study design type:
“Which allele of which gene is associated with the disease?
Association studies.
Name the genetic epidemiological study design type:
“Identified monogenic disorders & genes”
Traditional.
Name the genetic epidemiological study design type:
“Have led to discovery of many genetic polymorphisms that influence risk of developing many common diseases”
Genome-wide association studies (GWAS).
What is molecular epidemiology?
The use in standard epidemiologic studies of techniques of molecular biology.
What is life course epidemiology?
Study of antecedent exposures & later health outcomes.
Define health inequalities.
Differences in health status or in distribution of health determinants between different population groups.
Define incidence/incidence rate.
A measure of the frequency with which a new case of a disease occurs in a population over a period of time.
What is the equation for incidence?
What is the answer often expressed as?
= (new cases occurring during a given time period) / (population at risk during the same time period)
__ per 100,000 persons per year.
Define prevalence.
A measure of the frequency of all cases of a particular disease present in a defined population at a given time.
What is the equation for prevalence?
What is the answer often expressed as?
= (persons with a given disease/condition during a specified time period) / (population during the same time period)
%
Define mortality rate.
A measure of the frequency with which a new deaths occurs in a population over a period of time.
Define relative risk?
The ratio of the risk of disease among those exposed to a risk factor to the risk among those not exposed.
What is the equation for rate ratio?
= (rate for group of interest)/(rate for comparison group)
Rate Ratio = 1
=?
Identical risk in the 2 groups.
Rate Ratio > 1
=?
Increased risk for numerator group.
Define odds ratio.
Estimate of risk from case-control studies.
What is the equation for odds ratio?
(a x d) / (b x c)
where a = no. of persons with disease & with exposure of interest
where b = no. of persons without disease, but with exposure of interest
where c = no. of persons with disease, but without exposure of interest
where d = no. of persons without disease & without exposure of interest
In an odds ratio, a+c=?
Total no. of persons with disease (‘cases’).
In an odds ratio, b+d=?
Total no. of persons without disease (‘controls’).
Define a standard population.
A standard population is an artificial population structure that is used in the weighting of mortality or incidence data to produce age-standardised rates.
Define age standardisation/adjustment.
A method used to make fairer comparisons between populations with different age distributions.
Rate ratio is less than 1.
=?
Increased risk for denominator group.
