PPH Flashcards
What would we class as the modern age?
Industrial revolution onwards
When is the world’s rapid increase in population predicted to level off?
22nd centuary
What is the difference between the individual and population perspective of demography?
Individual - focus on health, risk factors, exposures etc.
Population - focus on mass disease, exposures, casual mechanisms
What perspective does epidemiology emphasise?
Population perspective
What are key events and process that drive a country’s population?
Birth, marriage, migration, aging, death
What are the key demographic characteristics that drive a country’s population?
Size/density, age, sex, place, ethnicity, education, economic resources
What does heterogenous mean?
Composed of disparate subpopulations
What is the trend of female fertility in the Uk in the last 40 years?
More women waiting to have children. Slight decline in under 20s having children
What is the most commonly sited birth rate?
Crude birth rate
How is crude birth rate calculated?
Number of births divided by an estimate of the total population at mid-year
How is the general fertility rate calculated?
Number of births in a year divided by the estimated number of women of reproductive age at mid-year
What are the formalities of presenting birth rate?
Express per 1000 and add per year at the end
Why is the overall death rate not often used?
Doesn’t take into account th edifferences in mortality between men and women.
Why is life expectancy not a prediction?
Because they are calculated with the mortality rates of the time. But mortality rates change.
What most heavily influences life-expectancy?
Mortality rates at young ages
“At a given age for an area is the average number of years a person would live, if he or she experienced the particular area’s age-specific mortality rates for that time period throughout his or her life” describes what measure?
Period life expectancy
“Calculated using age-specific mortality rates which allow for known or projected changes in mortality in later years and are thus regarded as a more appropriate measure of how long a person of a given age would be expected to live, on average than period life expectancy” describes what measure?
Cohort life expectancy
What has been the pattern of migration since the early 2000s?
Cyclic pattern
On which side of a population pyramid do males and females lie?
Males on the left and females on the right
What would you expect to see in the population pyramid of a slow-growth population?
Bands at base narrower than those in the middle - lower fertility rate
What is the rate of natural increase?
Difference between birth rate and death rate
What is the demographic transition?
general pattern of changes in death rates, population growth, and birth rates that appears during the process of modernization
What are the four stages of demographic transition?
Stage 1: Period before transition begins. Birth rate and death rate both high.
Stage 2: Transition period - death rates decline.
Stage 3: birth rate declines. Death rates stable.
Stage 4: Death rate and birth rate both low.
What big events had an impact on China’s population pyramid?
WW2/ Japanese occupation and the “Great Leap Forward” (approx 1960)
What is the dependency ratio?
Number of children and adults over 65 to the number of people of working age.
What is the sex ratio normally?
around 105 boys to 100 girls
What is Maslow’s Hierachy of Need?
Physiological Safety Love/ Belonging Esteem Self-actualisation
“A need which is identified according to a norm; such norms are generally set by experts”
Normative need
“A need concerning problems which emerge by comparison of others who are not in need”
Comparative need
“Need which people feel - that is, need from the perspective of the people who have it”
Felt need
“Need which people say they have”
Expressed need
What are the four categories of Bradshaw’s taxonomy?
Normative, comparitive, felt and expressed
What other factors affect a health needs assessment?
Supply and demand
“a systematic method for reviewing the health issues facing a population, leading to agreed priorities and resource allocation that will improve and reduce inequalities”
Health Needs Assessment
What are the preparatory stages of a health needs assessment?
- Define population
2. Identify stakeholders
What are the 3 types of Health Needs Assessment that must all be carried out?
Epidemiological (place, person, time), comparative (look at other similar systems), corporate (ask experts)
What is the nature of the health events and health information quality/ quantity pyramids?
Pyramid is inverted for quality/ quantity.
What is the second most prevalent cancer in the world for women?
Cervical
What is distribution?
Description of frequency, counts, rates or risks.
What is a descriptive study?
Describes cases and population, to formulate a hypothesis
What are the negatives of anecdote/ case series studies?
Not scientific, observer bias, difficult to make inference about disease cause.
What is a cross-sectional survey?
Snapshot of people with an outcome.
Count number of people with a disease in a short time period in a pre-defined population.
Good for prevalence estimation.
What are the disadvantages of a cross-sectional survey?
Only represents that point in time. Can’t estimate incidence. Sampling frame may lead to bias.
What is the counterfactual method?
Would the disease have happened
- at the same time in the same person
- anyway if the factor wasn’t present
What is an ecological study?
measure a group of people and compare it to another group of people
Odds ratio
odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure.
OR=1 there is no effect
OR>1 there is an association – the exposure raises the risk of the disease
OR
What is a case-control study?
Compare cases of the disease with controls without the disease for an ‘exposure’ = potential cause
This is ‘retrospective’
- after the disease has been diagnosed
What are the disadvantages of Case-Control studies?
Selection bias, participation bias, finding a suitable control group difficult, difference in recall
What is a cohort study?
Followed through time for the outcome.
People who share a common experience
What are some famous cohort studies?
Doll and smoking
Framingham Study (cardiovascular)
Atomic bomb exposure cohort
British birth cohorts (millennium cohort)
What are the disadvantages of cohort studies?
- Inefficient for rare diseases • Expensive
- Retrospective is quicker
- Loss to follow-up
What is prevalence?
Number of people who have a disease at one time
What is epidemiology?
Distribution and determinants of disease
What are the negatives of randomised control trials?
Not real life
• High cost
• Inappropriate/unethical for
many research questions
How can error due to sample selection be reduced?
Sample the “ignored” population
What is the ‘healthy worker effect’?
Workers self-selecting are more likely to be healthier as they remain at work
Unwell workers retire and don’t self-select
What is misclassification bias?
Data is placed into categories - subjective
What stages has public health been through historically?
1st dark age - some religions practice hygeine
1st golden age - Ancient Greece
2nd golden age - Ancient Rome
2nd dark age - Plague and pestilence
3rd dark age - Industrial revolution
3rd Golden age - Social reform and public health acts
4th Golden age - 20th centuary
What was the 1848 Public Health Act?
Local boards of health in districts with high death rates
Street cleaning, refuse collection, water supplies and sewerage.
Street paving and slum clearance.
Who were the figures for sanitation in public health?
Ignac Semmelweis
Joseph Lister
Oliver Wendell Holmes
What is the intervention ladder?
Do nothing Provide information Enable choice Guide choices through changing default Guide choices through incentives Guide choices through disincentives Restrict choice Eliminate choice
What is a necessary cause?
Can’t have the disease without exposure to the cause but exposure doesn’t always lead to outcome
What is a sufficient cause?
A factor whose presence leads to an effect. Exposure alone would induce the outcome but other exposures may induce the same outcome.
What is the hierarchy for health determinants?
General socioeconomic, cultural and environmental conditions
Social and community networks
Lifestyle factors
Biology
Geoffrey Rose’s Single population theory
High risk approach: identify and treat the “top end” of the population distribution
Population approach: shift the mean of the entire distribution to the left
What were the Wanless findings?
- Failure to move from “national sickness service” to “national health service”
- More incentives required focus to reduce the burden of disease by tackling the key lifestyle and environmental risks.
- Recognition needed that the NHS is only one contributor to public health
What is screening?
Screening is offering tests to a defined population, who do not necessarily perceive they are at risk, to identify those individuals who are more likely to be helped than harmed by further tests or treatment to reduce the risk of a disease or its complications.
What is sensitivity?
The proportion of people with the disease who are identified as having it by a positive test result
What is specificity?
The proportion of people without the disease who are correctly re-assured by a negative test result
What is the positive predictive value?
The probability that a person with a positive test result actually has the disease
What is the negative predictive value
The probability that a person with a negative test result does not actually have the disease.
When is high sensitivity desirable?
- Adverse consequences of missed diagnosis for individual
- Adverse consequences for society if missed diagnosis e.g. serious communicable disease
- Diagnosis can be quickly confirmed by other tests so not too much waiting/anxiety
When is high specificity desirable?
- Diagnosis comes with anxiety/ stigma
- Further investigations time consuming/ painful/expensive
- Cases likely to be detected by other means before too late
- Treatment is to be offered without further investigations to confirm diagnosis
What is lead time bias?
Early diagnosis falsely appears to prolong survival
What is length time bias?
Screening over-represents less aggressive disease
e.g. less aggressive cancers are more likely to be found by screening as more aggressive cancers kill you quickly. Therefore misconception that if you catch cancers early they’re less dangerous.
What is the second most common cancer in men in the UK?
Prostate
What are the Wilson and Jugner Criteria?
For screening to take place:
- Important condition
- Acceptable treatment available
- Facilities for diagnosis and treatment available
- Recognised latent/ early symptomatic stage
- History/ progression of condition understood
- Suitable test/ examination
- Test/ examination acceptable to the population
- Cost of case-finding balanced with possible expenditure as a whole
- Case finding a continuous and not “once for all” process
What body is in place to decide on screening programmes?
National screening committee
What is the hierachy of studies?
- Anecdote
- Cross-sectional study
- Register/ecological studies
- Case-control study
- Cohort
- Randomised controlled trial
