Breast Cancer Epidemiology Flashcards
What is the WHO 1946 definition of health?
A state of complete physical, mental and social wellbeing, and not merely the absence of disease and infirmity
What is the BMJ 2007 definition of Health?
Health is a condition of well being free of disease or infirmity and a basic and universal human right
What is Disease?
A deviation in bodily structure or function which places the individual at biological or social disadvantage, now or in the future
What is disease a balance of?
- biological abnormality
- symptoms
- social consequences
this relative balance will differ between diseases
What might the biological, Sx and social aspects of DM look like?
Biological: clear abnormality, detected early for some types
Sx: variable, may be late to develop
Social: variable, may be late effect
What are the considerations when trying identify healthy individuals from those with a disease?
- key part of medical practice
- ideally, disease will be associated with clear Sx and signs
Monogenic - clear distinction between diseased and healthy individuals
Polygenic/complex disease: continuum of impaired function and disease/Sx development. Can be difficult to ID pope with that disease
How is health separated from disease?
- Sx, clinical abnormalities
- statistical basis (more than 2 SDs around mean) of biological parameter
- using a predictive parameter for associated morbidities in the future
- Treatment: level at which condition will benefit from Rx e.g. hypertension
What is the epidemiological timeline of disease?
healthy -> at risk -> morbidity -> mortality
Morbidity -> recovery
(And interaction with health services)
Measuring these stages can give an indication of DISEASE BURDEN
What are the simplest indicators of health status in the population?
- mortality
- morbidity
- health service use
- (risk factors)
How is mortality or death rate recorded?
compulsory registration of deaths since 1874
What info is recorded for death registration?
- fact that death has occurred
- characteristics of deceased
(age, place of birth, place of death, occupation, social class) - cause of death
How is the cause of death assessed in death registration?
- certified by medical practitioner/coroner
- coded in accordance with the International Classification of Diseases (ICD10)
What are the main categories of the death certificate?
- disease or condition directly leading to death
- other disease/condition leading to CoD (x2)
- other significant conditions
- Cause of death
Where is the info on death collated?
NHS Central Register and Office of National Stats
What does info or deaths provide?
- interpret info for DEATH RATE
How is the death rate calculated?
number of deaths / population / year
Where is info on the living population gained from?
Census performed every 10 years
managed by office of national stats
What info does the Census include?
every 10 years, next one in 2021
complete count of population
age and sex distribution
suppl info: Birthplace, ethnic origin and occupation
What kind of info does the ONS keep of the living population?
- total population at time of consensus
- immigration and emigration
- deaths
- births, stillborns, abortions
- year by year estimates
- death rates (annual)
- cancer registration and disease notification: incidence rates
- deaths by a particular cause e.g. breast cancer
Why is crude death rate not the informative for breast cancer?
death varies strongly by age
average means that you’re diluting the effect
What are the 2 approaches that are used to deal with the idea that death rates vary with age?
- AGE-SPECIFIC
= death rates over a narrow age-range - AGE STANDARDISED
= summary of age-specific death rates over wider age range
How it the AGE-SPECIFiC mortality rate calculated?
number of breast cancer deaths in age range / number of women aged in that range (per 1000)
given per year (rate)
What are the classic age divisions used for age-specific mortality rate?
45-54
55-64
65-74
etc
What is the relationship between age-specific mortality and age in breast cancer (women)?
increasing age-specific mortality rates with increasing age
[continuous effect]
What is the importance of age-specific mortality rates?
- death rates vary markedly with age
- provide a much more precise death rate estimate
- can be compared with other populations
- Comparison: especially when different populations have different age structures
What is the age structure of South Africa compared to Sweden?
S. Africa: majority of population is v. young <30yo. Very few make it to 70+
Sweden: much more of an even distribution between all age ranges
less stark of a difference between very young and very old
What is the AGE-STANDARDISED mortality rate?
summary of data rates across a broad range of age-groups, taking population age differences into account
Why is AGE-STANDARDISED mortality rate useful?
comparing death rates in different populations (esp when comparing different age structures and times/places)
What are the 2 types of AGE-STANDARDISED mortality rate?
- direct
- indirect