Epidemiology Flashcards
What is Epidemiology
The study of populations in order to determine the burden – frequency, distribution and trends of disease
What are the major roles of epidemiology
Monitor infectious and non-infectious diseases
Study natural history of diseases
Investigation of disease risk factors
Health care needs assessment
Development of preventive programmes
Evaluation of interventions
Health Service planning
What is epidemiology necessary for
To allow appropriate planning of health services
What are the three main types of epidemiological study
Descriptive (observational)
Analytic (observational)
-Case-control
-Cohort
Intervention / experimental
How is disease frequency measured
Prevelance
Incidence
What is prevelance
A measurement of all individuals affected by the disease within a particular period of time or point in time
What is incidence
Incidence is a measurement of the number of new individuals who contract a disease during a particular period of time
What is the prevelance and incidence of diabetes vs common cold
Diabetes:
High prevelance (because the prevalence is the cumulative sum of past year incidence rates)
Low incidence
Cold:
Low prevelance
High incidence (because many people get a cold each year, but few people actually have a cold at any given time)
What are the advantages of studying samples and not whole populations
reduces no. of individuals to be sampled
reduces cost
higher response rate
higher quality of information collected
What is a systemic sample
indivs. selected at regular intervals from population list
What is a stratified sample
ensures small sub-groups adequately represented
What is a cluster sample
use of groups as sampling units, e.g. school classes
What is multi-stage sampling
Combines multiple sampling techniques
What are some sampling techniques
Simple random sample
Systematic sample
Stratified sample
Cluster sample
Multi-stage sampling
What are common erroes in survey methodology
Sampling bias / selection bias
Response bias / information bias
Measurement error
Observer variation (intra- or inter-)
Loss to follow-up
What are the properties of an ideal index
clear, unambiguous, not subjective
ideally correspond with clinically important stages of the disease
indicate treatment need
within the ability of examiners
reproducible
not time-consuming
acceptable to patient
amenable to statistical analysis
allow comparison with other studies
What are limitations of the DMF index
Teeth extracted for reasons other than caries
Influenced by access, e.g. interproximal surface
Difficulty in differentiating fissure-sealant from restorations – underestimate caries
Influenced by past disease activity
Threshold criteria of disease can vary (must specify)
Cannot be used for root caries
What is very early stages of decay
Sub-clinical decay
What is early stage of decay
Decay in enamel (visible)
What is established decay
Decay in dentine (visible)
What is severe decay
Pulpal decay
What is BASCD
British Association for the Study of Community Dentistry
What does SHBDEP stand for
Scottish Health Boards’ Dental Epidemiological Programme
What replaced SHBDEP
National dental inspection programme (NDIP)
What does the NDIP aim to inform
parents of their child’s dental health status (Basic NDIP)
advise Scottish Government, NHS Boards, and other organisations of the oral disease prevalence in children in their area (Detailed NDIP – Epidemiology survey)
What does NDIP target
Children in P1 and P7
What is the NDIP basic
Offered to every child in P1 and P7 classes of local authority schools every year
Proportion of school rolls inspected 85-90%
Generates letter to parent
Overall state of dental health of child
Conveys degree of urgency with which appointment for attendance at dentist suggested for child
Not a detailed examination of each surface of each tooth
What is the detailed NDIP
more rigorous and comprehensive assessment
Calibration of examiners
records status of each tooth surface in accordance with international epidemiological conventions (i.e. d3mft: caries into dentine)
Uses same clinical inspection criteria as SHBDEP
can therefore look at trends from 1987 re P1 children
What are the specific goals of NDIP
to inspect a representative sample of the P1 or P7 LA school population in any year
to determine current levels of established tooth decay
to illustrate the impact of deprivation on the dental health of 5 & 11 year old children in Scotland
What does TF4 mean
Flurosis index (high levels of flurosis)
What is the IOTN
Index of orthodontic treatment need
What is the purpose of the IOTN
Assesses need and eligibility of children for NHS orthodontic treatment on dental health grounds
Selects those children who will benefit most from treatment; fair way to prioritise limited NHS resources
When would a child be eligible for NHS orthodontic treatment
Above or equal to Grade 3 dental health component and high aesthetic component
What indices are used to identify periodontal disease
Plaque indices, e.g.
- Debris Index (Green & Vermillion, 1960)
- Plaque Index (Silness & Loe, 1964)
Gingivitis indices, e.g.
- Modified Gingival Index (Loe, 1967)
- Lobene Index (Lobene, 1986)
Periodontitis indices, e.g.
- Basic Periodontal Examination (B
