Lecture 14. Non Communicable Disease Epidemiology: Making Associations Flashcards
What association did Richard Doll find in 1948?
Smoking and lung cancer
What was Doll’s approach that became established practice?
- Obtain the best quality data you can given the
circumstances - Find the associations
- Test them. Are they statistically valid?
- Then try to disprove your conclusions by performing
different studies.
What are retrospective studies?
Examines exposures to risk/protection factors in relation to an outcome that is established at the start of the study. E.g rise in lung cancers
Often criticised: errors and bias are more common in retrospective studies than in prospective studies.
Here you don’t know what data/information will be
available
What are prospective studies?
Examines outcomes, such as the development of a disease, during the study period and relates this to other factors
such as suspected risk or protection factor(s).
Usually involves taking a cohort of subjects and watching them over a long period.
Usually have fewer potential sources of bias than retrospective studies.
Here you can have designed your study to track exactly the data you need
What did the prospective study of the effects of smoking on British doctors show?
It confirmed the connection with lung cancer
It showed how risk related directly to the extent of
smoking
It showed that chronic bronchitis and coronary disease were also linked to smoking
How long did it take after the study for tobacco to be taxed on health grounds?
25 years
When was the UK smoking ban passes?
2007
Where is lung cancer more prominent in the UK?
The North
How many cancers are thought to be avoidable?
4 in 10
What cancer is 100% avoidable?
Cervical
What cancers are 0% avoidable?
Testicular and prostate
What is the prostate specific antigen (PSA)?
A protein produced by normal prostate cells and prostate cancerous cells
It is normal to have it in the blood
Levels raise with age as the prostate gets larger
Levels above 3ng/mL are associated with/an indicator of prostate cancer
What are the advantages of PSA testing?
Can detect prostate cancer before symptoms arise
Possibly detecting a fast-growing cancer at an early stage, where intervention may halt the spread and prevent health problems
Detection of increased PSA may not mean prostate cancer, but may be an indicator that an individual is high risk
What are the disadvantages of PSA testing?
A raised PSA level don’t necessarily mean prostate cancer
A low PSA level may not mean no prostate cancer
Raised PSA levels may lead to more tests, including a biopsy. Biopsy can cause side effects such as pain, infection and blood in the urine and semen
Why would an yearly prostate cancer screening be useful?
Baseline to compare to
Track any changes
