Beginning Flashcards
Cases of new events?
Incidence
Prevention programmes effectiveness can be detected using?
Incidence rates
What type of value is prevalance?
Proportion not rate
What type of value in incidence?
Rate of cases per person per year
Limits of incidence?
Doesn’t show you the burden in community
IR and mortality rates enable…?
Comparison of different pop to see if individuals are at higher risk, despite difference to the pops and length of observation
What are prevalence rates needed for?
Need for services in community or population
What is point prevalence?
sufferer / # at risk
Does prevalence have a time element?
No
Systematic variation?
See the risk between people in order to work out causes of disease to help prevent and treat
IRR equation?
Rate (exposed) /Rate (unexposed)
Uses of IRR?
Compare 2 groups of different exposure levels to determine causality
How would an IRR indicate that an exposure is linked to disease?
Number is greater than 1.
Rate exposed > unexposed
MRR?
Mortality Rate Ratio is Rate A/Rate B
Determines effectiveness of treatments
Absolute risk shown by?
Rate
Relative risk shown by?
Ratio - no units
Why is point prevalance important?
See how many people at risk. Can plan resources
Nuisance variation?
Counfounders.
Variation that can be determinants of health hence hide the true causal effects.
Age and sex are strong cofounders as older people usually have higher rates.
Why is age a bad thing when it comes to con founders?
Age is non-modifiable hence a serious confounded and gets in the way of useful, modifiable characteristics
How are cofounders adjusted for?
Age-sex standardisation
What is Age-Sex standardised mortality rate?
SMR
Adjustments used by comparing the level of mortality observed / expected
Define census?
Simultaneous collection of demographic data by government at a particular time to all persons living in a particular territory
Census are used for?
Population Health Transport Housing Employment Ethnic groups
How’s does the census affect NHS?
Allows to plan and allocate services effectively,
ie lots of potential mothers hence make more nurseries
How does census affect health?
Age and socio-economical background can predict long term general health
Employment?
Government may need to increase jobs and training
Transport?
Pressures on public transport, number of cars, road planning
Ethnic groups?
To determine in different groups are receiving the adjustments they require as well as success of equal opportunities
Positives to census?
Includes household and people Most accurate Universal coverage Regular intervals Pop size - rates Pop structure - services Pop characteristics- deprivations, pensions
Negatives to census?
May double count
Missed homeless and runaways - those with worst general health
What happens when someone is born?
Birth notification within 36 hours and provide immunisation
Registration by parents for statistical purposes
What is the crude birth rate?
live births per thousand people in a population
What is GFR?
General Fertility Rate #live births per thousand of the fertile women population aged 15-44
What is TPFR?
Total period fertility rate
Sum of all fertility rates in each age group per year
Hence average number of children born to a hypothetical woman in her life
Fecundity definition?
Physical ability to reproduce
What is fertility?
The realisation of the ability to reproduce
SMR calculation?
(Observed #deaths / Expected #deaths) X 100 to give a RATE
SMR > 100 means?
Excess mortality with sex and age and cofounders adjusted
What happens when someone dies?
Certification by doctor - as Info for cause of death
Registration
What is CDR?
Crude death rate #deaths / thousand
IR = 0.0045 per thousand per year. Convert into per thousand p-y
0.0045 X 1000 = 45 per thousand person years
What is ASDR?
Age-specific death rate #deaths/thousand in an age group
With SMR, what can be assumed about the populations?
The age-sex distribution is equal
What is health information used for?
Investigate trends - comparing rates over time, places, socio-economical groups
What could be vary the numerator in rates?
Death classification
Disease diagnosis - changes in techniques
Coding errors - bridge coding hence compare new rates using old coding rules
Chance
Demography over time- ageing pop increase CDR
What can vary the denominator for rates?
Population used
Population defined
Population count
How can trends be interpreted?
Chance
Artifactual reasons - systematic variation
Real due to natural epidemiology or medical care effects
Which birth rate is best?
GFR - better than crude but may lack resources
CBR- can show affects to general population
Best is TPFR as sum of current age specific fertility rate as breaks down the ages and takes it into account, whereas GFR lumps together all fertile women and CBR lumps together everyone
What is TPFR good for?
Annual and internal comparison
Pop size and age removed
Most accurate
298700 women at aged 15 had 1016 births. What is the TPFR?
TPFR is 1016/ 298700 (=really small #) at aged 15.
Hence need to calculate for all age groups from 15-44 then sum together to give total.
What is CDR good for?
ImpCt on whole pop
What is ASDR good for?
Comparison with age co founder removed hence better indicator. SMR most accurate
In SMR, what is often the standard reference population?
The whole general public of UK
