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Flashcards in The Epidemiological Approach Deck (12):

What is epidemiology briefly?

Finding causes of disease and preventing disease


Percival Potts noticed that a high proportion of his patients with scrotal cancer were/had been chimney sweeps. These results were limited to Britain. Why?

The difference was that British chimney sweeps did not
bathe regularly compared to chimney sweeps in Germany for example.


Why is lung cancer more common in men?

More exposure to pollution e.g. due to occupation
Smoke more


What type of study is used to investigate the relationship between smoking and lung cancer?

Prospective cohort study


What are the problems with a cohort study? (3)

Need very large numbers to draw firm conclusions


What type of study is quicker than a cohort study?

Case control study


How can the relationship between saturated fat intake and ischaemic heart disease be assessed?

A study to assess the link between saturated fat intake and serum cholesterol, and a study to assess the link between serum cholesterol and IHD. Together they show the relationship between fat intake and IHD.


What is PKU?

Phenylketonuria, an inborn error of metabolism in which there is a congenital lack of the enzyme phenylalanine hydroxylase.


What does phenylalanine hydroxylase do?

Converts phenylalanine to tyrosine


How can PKU be prevented?

Restricting dietary phenylalanine


Anti-platelet drug (aspirin) prevents 30% of cases of heart disease
Cholesterol lowering drug (statin) prevents 60%
Blood pressure lowering drug prevents 20%
How many cases can be prevented by all three drugs together?


Working out:
100 cases of the disease.
30 would be prevented by aspirin.
This leaves 70, of which 60% would be
prevented by the statin = 42 cases.
This leaves 28, of which 20% would be
prevented by the blood pressure lowering drug = 6.
30 + 42 + 6 = 78
Therefore 78% of cases prevented.


What is the definition of a cause of a disease?

A factor that is associated with the disease so that if the
intensity or frequency of the factor in a population is changed, the frequency of the disease also changes.