Public Health Flashcards
Define Health
Complete state of mental, physical and social well-being. Not just the absence of disease.
Define public health
The science and art of preventing disease, prolonging life and promoting health through organised efforts of society, organisations, public and private communities and individuals.
The key features of public health
1) Health promotion
2) Health protection
3) Service improvement
Health promotion ?
- Lifestyle changes
- Overcoming inequality
- Education
Health protection ?
- Infectious disease and natural disaster management
- Emergency responses
Service improvement?
- Efficiency
- Efficacy
- Audit
- Governance
Prevention; types?
Primary - prevent before it occurs
Secondary - Limits impact of disease
Tertiary - Manages disease complications.
Prevention paradox
If something brings benefit to a population it often has little benefit to the individual; wearing seatbelts.
6 in 1 immunisation; what is it and when is it given?
- diptheria
- tetanus
- Pertussis
- Polio
- HIB
- Hep B
8w, 12w, 16w
Screening; Types?
- Primary - identifies those at risk and screens to prevent disease from occurring.
- Secondary - aims to find the disease in it’s early stages.
Wilson and Junger criteria
1) Condition should be important
2) natural Hx should be understood
3) Recognisable latent phase
4) Rx should be acceptable
5) Facilities for Dx and Rx should be available
6) Adequate health service provision should exist for those found +’ve.
7) Suitable test for early stage
8) Acceptable test
9) Should be repeatable
10) Agreed policy on whom to treat
11) Costs should be balanced against benefits
12) Risks, psychological and physical should be less than risks
Screening programme examples;
- Breast cancer
- Colon cancer
- STI
- Diabetic retinopathy
- Newborn screening
- Cervical smear
Cervical screening
- High risk HPV (16/18)
- Screening 25-64 (25-50 every 3yrs)(50-64 every 5 yrs)
- Gardasil protects against 6,11,16,18
Breast screening
- 50-70yrs
- every 3 yrs
- Triple assessment if positive.
Antenatal screening
- 1st trimester (combined - nuchal translucency, PAPP-A, bHCG) and maternal infections (Hep B, HIV, malaria)
- 20 weeks anomaly scan
NIPE
- Newborn hearing test
- Newborn physical exam
- Guthrie test - MCADD, Sickle cell, CF, congential hypothyroidism, maple syrup disease, PKU.
False positive
Some people will be screened and found to be positive when infact they are not.
False negative
Some people will be screened and shown to not have a disease when infact they do.
Sensitivity
- The proportion of people who are screened positive who actually have the disease.
True +’ve/(True +’ve + False -‘ve)
Specificity
The proportion of people who are correctly excluded via screening
True negative/(False positive + True negative)
Positive predictive value
- Proportion of people who have a positive screening test and have the disease.
True positive/ (true positive + false positive)
Negative predictive value
- Proportion of people who have a negative result who do not have the disease
True negative/ (False negative + true negative)
Selection bias
- Essentially those who partake in screening may be a certain subset of society (worried well) which may influence results.
Length time bias
- Screening happens at regular intervals.
- Disease may develop in the intervening period
Lead time bias
- Positive result may not actually influence survival the patient may just be aware of disease for longer which makes it appear like extended survival when without screening they would have been perfectly fine.
Epidemiology
Study of frequency, distribution and determinants of disease and health related states in the population.
Prevalence
All existing cases at a point in time
Number of cases at one point in time / total number of people in the defined population at the same time period.
Incidence
All new cases within a time period in a population.
Risk
- Total number of cases in a defined population at risk over a time period.
- Likelihood that someone will develop an outcome in a time period.
Number of new cases among contact group in a specified time period / total number of people at risk in the same time period.
Odds
- Ratio
- Ratio of risk that a person will develop the outcome during a time period
Number of new cases in a time period / number who did not become a case in the same time period.
Endemic
Persistent level of disease
Gillick competence
- Medical treatment
- Whether a child under the age of 16 can give consent w/o the need of parental knowledge or permission.
- UNDERSTAND, REASON, RETAIN, RESPOND
Fraser Guidelines
- Refer to contraception only.
- The girl will understand the advice
- Cannot be persuaded to inform parents
- Will continue to have intercourse either way
- Her physical or mental health may suffer if she doesn’t get the contraception.
- This is in her best interests.
Observational studies
- Cohort (analytical - looks at who was exposed and non-exposed and whether they have the disease or not)
- Case control (analytical - looks at who was exposed or not from cases of a disease (retrospective))
- Case report (descriptive)
- Cross sectional (descriptive)
Ecological studies
- Carried on a population level.
- In their own environment
- Looks for associations not causality