RISK FACTORS, CAUSALITY, BRADFORD HILL CRITERIA Flashcards
when was bradford hill criteria made
1965
what is bradford hill
Widely recognised as a basis for causality assessment in epidemiology
In order to say that an association is causal, it should meet as many from this criteria as possible:
1) Strength of the association
2) consistentecy
3)Specificity of the association
4) temporlaity
5) Biological gradient
6) plausible
7) coherance
8) experiment
9) analogy
most common risk measures
1) RR
2) attributable risk
3) ODDS
WHAT would make something a protective factor
if the RR <1
define Relative risk
help you remember you are dividing
A ratio of the incidence in the exposed group (IE) compared to the incidence in the unexposed group (INE) ∴ IE/INE
e.g smoking in causing cancer for example
attributable risk
help you remember you are taking away
the difference between the incidence in the exposed group and the incidence in unexposed group ∴IE – INE
odds ratio
the relationship pf the probability of occurrence of an event to that of non- occurrence.
what gives you A snapshot of disease distribution in a population at a given moment.
incidence
difference bbetwen incidence and prevelence
time interval in incidence you need to have a time interval
Methods for studying incidence
Sources:
Data from the patient and his/her family
Data from medical establishments
Data from death registries
morbity
any departure, subjective or objective from a state of physiological wellbeing. Usually accept as a statistical concept including all cases of diseases that the health system is informed about.
“Epidemic situation
Low level of health prevention and treatment”
what does this mean
high incidence and high prevelence
which group does an aged popuplaution fall under
low incidence + high prevelence
confounding variable
A confounding variable is a third variable that influences both the independent and dependent variables.
it has to affect both
e.g alchol and heart disease
but smking is a confounding variable as it affects both
definition of risk
Generally, risk refers to the probability that an event will
occur. In epidemiology, risk refers to the probability that
person, exposed to certain factors (risk factors) will
subsequently develop a particular disease.
whats odds ratio usually measured with
case control
definition of proportion
Proportion is a ratio, measuring the number of specific events
out of total events. For example, the proportion of male patients
in a hospital is the number of males / all patients.
definiton of ratio
Ratio is a quantitative measure of the relationship of two
(independent) rates or events which may not be a part of the
same denominator. For example, sex ratio is the number of men
/ number of women.
definiton of ratio
Ratio is a quantitative measure of the relationship of two
(independent) rates or events which may not be a part of the
same denominator. For example, sex ratio is the number of men
/ number of women.
definition of rate
measures the occurrence of an event in a population
over time. The persons in the denominator must reflect the
population from which the cases in the numerator arose. The
counts in the numerator and denominator should cover the same
time period. The persons in the denominator must be “at risk”
for the event, that is, it should have been possible for them to
experience the event.
low incidence and low prevelence
Good level of health care
services with successful prevention and treatment of diseases
ICD
is a system developed collaboratively between the World Health Organization and 10 international centres so that the medical terms reported by physicians, medical examiners, and coroners
on death certificates can be grouped together for statistical
purposes.
- The purpose of the ICD and of WHO sponsorship is to
promote international comparability in the collection,
classification, processing, and presentation of mortality
statistics.
MOST CURRENT ICD
11 is officially in use
35 countries are using 11
youtube video on odds
> 2 - considered meangingful
4- very strong
