dph Flashcards
define epidemiology
- study of the distribution of (oral) diseases in a population
why is epidemiology important? (3)
- helps population needs assessment to inform PH policies, planning, resource allocation
- assesses impact of health promotion activities/policies
- identifies changing patterns and population risk factors
define normative need
- professionally defined health needs
- assessed with clinical measures (eg indices for national surveys)
define felt/perceived need
- lay person perception of their need, “wants”
- assessed with self-rated questionnaires
define expressed need
- felt/perceived need translated into action by utilising healthcare services or requesting information
- “demand”
define comparative need
- need is not evenly distributed among similar groups of people
- assessed by comparing oral health needs between groups of people
what is an index? (3)
- method of quantifying disease
- relative numerical value (usually) describing a population on a scale
- allows comparison with other populations
properties of an ideal index (8)
- objectivity
- acceptability
- simplicity
- amenable to statistical analysis and interpretation
- reproducibility
- validity
- reliability
- precision
give some examples of indices in oral health (up to 8)
- DMFS/dmfs
- ICDAS
- gingival index, plaque index
- IOTN
- BEWE
- BPE or CPI
- trauma index
- PUFA
define prevalence (of disease)
amount of disease present at a given point in time (often as a percentage)
define incidence (of disease)
change in disease in a given period of time (rate)
what are the advantages and limitations of using perceived need?
+:
- person-centred, accounts for psychological aspects and QoL
- cheaper, less complicated to assess
-:
- subjective, less reliable than normative need
- influenced by individual’s characteristics
what are the main two types of epidemiological studies?
observational and interventional
list different types of observational studies (4)
- ecological
- cross-sectional
- case-control
- longitudinal
list different types of interventional studies (3)
- randomised controlled trials
- non-randomised controlled trials
- pre-post study
what is a observational study and its general pros/cons?
- researcher collects information without influencing events
- = cost-effective, quick, large samples
- = cannot prove causality
what is a interventional study and its general pros/cons?
- researcher deliberately influences events and investigates the effects of this
- = can establish causality
- = more expensive, dropout rate, ethical considerations, not applicable to all populations
what is an ecological study and its specific pros and cons?
- observational study comparing trends in different populations
- = generate hypothesis, able to compare
- = no individual data, bias/ecological fallacy, difficult to control for confounders
what is a cross-sectional study and its specific pros and cons?
- observational study where the population is assessed randomly at the same time point (eg ADHS)
- = individual data and control of confounders, assess multiple outcomes, hypothesis generation
- = cannot prove temporality or causality
what is a case-control study and its specific pros and cons?
- observational study with pts assigned to case/control groups and matched by potential confounding factors
- = efficient for rare diseases, individual data
- = hard to do retrospectively, recall bias, rarely proves temporality
what is a longitudinal study and its specific pros and cons?
- observational study with collection of data at different time points
- = demonstrates temporality (establish RFs and disease incidence)
- = long if prospective, may miss some confounders
what is a randomised controlled trial and its specific pros and cons?
- interventional study with homogenous randomly assigned intervention/control groups +/- blinding
- = causality
- = may be long, risk of high dropout
what is a non-randomised controlled trial and its main disadvantage?
- weak interventional study with non-random intervention and control groups
- risks bias as it lacks randomisation
what is a pre-post study and its main disadvantage?
- interventional study assessing a group before and after an intervention
- any changes in disease outcome cannot fully be attributed to intervention