Epidemiology III Flashcards
(46 cards)
why study epidemiology
To understand burden and causes of disease
Population studies
Unnecessary to study whole population to obtain valid information about a population
Sample population must be representative of population being investigated
- Some tests only received by those who suspect they have – miss asymptomatic carriers
Evidence Based Dentistry (Medicine)
- Make sense of epidemiological studies And studies in general
- Should we believe the results
role of epidemiology
Measurement of amount and distribution of disease, and natural history of disease
Study of causes / determinants of diseases
Assess people’s risk of disease
Health care needs assessment and Service planning:
- Development of preventive programmes
Evaluation of interventions e.g.:
- caries preventive programme
- oral cancer screening
- clinical trials for drugs / treatments
3 aspects of epidemiology
descriptive
analytical
intervention - assessing intervention/programme
prevalance
Number of disease cases in a population at a given time
P - Point in time = Prevalance
Prevalence estimates obtained from cross-sectional studies or derived from registers
Can relate attributes to absence / presence of disease lead to development of a hypothesis
Used for chronic disease or high fatality e.g. diabetes
Prevalence =
Number of affected individuals (cases) /
Total number of persons in population
prevalence used for
chronic disease or high fatality e.g. diabetes
incidence
Number of new disease cases developing over a specific period of time in a defined population
Incidence estimates obtained from longitudinal studies or derived from registers
E.g. cancer (10 per 100,000 per annum), covid
Need timeframe and population size
incidence Rate =
no. of new cases of a dis. in a period /
no. of individuals in the pop. at risk
incidence needs
Need timeframe and population size
rate
prevalence estimates obtained from
cross-sectional studies or derived from registers
incidence estimates obtained from
longitudinal studies or derived from registers
distribution
How common is X?
How is X distributed in the population?
When OR time
Where place
Who person
dental caries in children
epidemiology
Epidemiology in the community
Dental Indices: DMFT / dmft
Sources of information / routine data
SHBDEP and NDIP (national dental inspection programme)
dental examples of epidemiology studies
dental caries in children
adult oral health
periodontal disease
oral cancer
oro-facial trauma
epidemiological indices
To measure disease an appropriate index is needed
Measuring for the purposes of epidemiological studies is different from recording disease for patient treatment purposes
dental epidemiology in the community - measuring caries
p1 and P7 children (5 and 11 year olds)
on a school table, public dental service
a simple assessment of the mouth of each child using a light, mirror and ball-ended probe
- specific strength of lightbulb with safety catch - standardised
DMFT / dmft
recorded on a laptop
letter sent to parent/carer - done on opt out (negative consent basis)
data analysed
properties of ideal index
clear, unambiguous, objective not subjective
ideally correspond with clinically important stages of the disease
indicate treatment need
within the ability of examiners
- train to be standardised
reproducible
not time-consuming
acceptable to patient
amenable to statistical analysis
allow comparison with other studies
DMF/dmf Index
DMF (permanent)
dmf (deciduous)
DMFT: decayed, missing & filled teeth (0-32)
DMFS index
decayed, missing & filled surfaces (0-148)
- Not incisal of upper and lower 3-3
def/dmf index
dmft: decayed, missing filled teeth (0-20)
‘e’ = indicated for exfoliated
D3MFT/ d3mft
signifies decay into dentine
D1MFT/d1mft
decay into enamel
- obvious to naked eye
when DMF index created
1937
worldwide use
reasons for teeth to be missing
caries periodontal disease trauma exfoliation (age - mixed dentition from 6) congenitally missing
