Demography and populations Flashcards
Define demography
The study of the size, structure, dispersement and development of human populations
What is a census?
The simultaneous recording of demographic data by the government at a particular time pertaining to all the persons who live in a particular territory
Uses of the census
Projections and estimates of population size
Trends In population characteristics
Highlights regional differences
Provides data for planning services
Material deprivation (ome ownership, car access, amenities)
Some health information
Uses of mortality data
Planning
Public health monitoring
Outcome indicator of healthcare
Define morbidity
Any departure, subjective or objective from a state of physiological or psychological well-being. In this sense, sickness, illness and morbid condition are similarly defined (synonymous)
Uses for cancer registration
Epidemiological studies Management planning of services for prevention and care Healthcare research Evaluation of screening programmes Survival studies from malignant disease
What is the Health Survey for England
Annual survey using a random sample of 16000 adults 16+ and 4000 children in private households.
Includes health and socio-economic questionnaire
physical measurements (height, weight bp)
blood sample tested for Hb, Ferritin, cholesterol.
Hospital episode statistics (HES)
Contains details of all admissions to NHS hospitals in England
Use of demography
To establish reliable statistics on
- birth and death rates
- marriages and divorces
- life expectancy
- migration
Framework for assessing quality of Health Information
Completeness: how much of the data is missing
Accuracy: is it correct? Has there been adequate coverage
Representativeness: is it relevant to the question, is it representative of the population
Timeliness: completed within the required time
Accessibility: who has access
Value of census to health
Knowledge of population size & structure are strong determinants for needs in healthcare
Base population used to evaluate disease in a population
Measures of material deprivation used to identify and target inequalities
Measures of fertility
Crude birth rate: live births/1000 population (includes men, infertile women)
General fertility rate: live births/1000 women aged 15-44
Total fertility rate: average number of live children that a group of women would have if they experienced the age-specific fertility rates of the calendar year in question throughout their child-bearing lifespan.
Birth registration
Birth attendant ( midwife) notifies health authority within 36hrs Birth registration by parents to local registrar within 42 days
Both submitted to ONS
Death registration
Death certificate issued by doctor (certifies age, place and cause of death)
Death registration by informant within 5 days to local registrar
Submitted to ONS
Population estimates
Estimate of population size and structure between census
Census baseline+ births - deaths +/- migration
Strengths of making population estimates
More up to date than census
More accurate than projections
Weaknesses of population estimates
Less reliable with time from census
Poor information on migration
Says nothing about future
Population projections
Forecast future population size and structure, based on assumptions about mortality, fertility and migration
Strengths of population projections
Can be used for longer term planning
Weaknesses of population projections
Less accurate the further ahead
Unforeseen changes of past trends can invalidate projections
Why is notification of communicable disease important?
Uses:
To prevent further infection
Identify outbreaks
Surveillance to monitor trends
Main disadvantages of surveys
Responder bias: non-responders likely to be those who are have the poorest health (eg. Obese, poor glucose management)
Reporting bias: values can be over or under estimates e.g. Self-reporting of weight tends to be lower than true value
Causes of a change in trend over time
Chance Artefact (change in population size/structure, accuracy or completeness) Real change (natural change in disease or medical care effects
3 examples of low enumerated groups in the census
Students (unsure whether residence is term-time or parents)
Travellers
Babies (left off the form)
Elderly (living alone, accessing form)
Young people (20-29) (lifestyle and multi-occupied housing)
Ethnic minorities (language barrier, suspicion)
Strengths and weaknesses of mortaility data
Complete coverage
Gives important information of health of the population
Underlying CoD subject to errors such as incorrect diagnosis, omissions in recording
Doesnt give reliable picture of morbidity
Ethnicity not collected
3 sources of morbidity data
Cancer register
Notifications of communicable disease
NHS activity data
Strengths and weaknesses of notification of communicable disease
Timeliness - weekly return to HPA
Representative - routine national data
Linked to other data to improve accuracy
Poor variable completeness for some diseases (e.g. food poisoning, colds)
Low accuracy, asked to notify suspected cases.
Two main clinical classifications used in HES
ICD-10: international classification of diseases. Describes conditions treated or investigated
OPCS-4: classification of surgical operations and procedures. Records details of operations
Strengths and weaknesses of QoF data
Almost 100% response from GPs
Representative of all the population
Updated annually
Accessible online
Excludes practices who do not participate Unsure how complete disease registers are for individual practices Aggregated data (no age, sex breakdown)
QoF
Requires GPs to record information on number and clinical management of patients with chronic diseases and the care they receive.
Information collected is used to produce a set of quality scores which are linked to payments. Data can be used to estimate the incidence and prevalence of different diseases and assess the quality of care in general practice.
How do population pyramids help in the design of services?
Age and sex are strong determinants for the need of health services. Knowledge of the breakdown is essential to plan which services are needed. Population pyramids also allow forecasting of future service needs.
What things to do you need to consider when interpreting trends over time?
Need to consider whether the change is due to:
- Chance
- Artefact: change in numerator (completeness of data or accuracy varies over time), change in denominator (change in population size or structure)
- Real change: natural change in disease or effects of medical care.
