Necessary, Sufficient, Proximal And Distal Causes

Question 1

What are necessary and sufficient causes?

Answer 1

These causes are required to be present to develope a disease - once present they inevitably lead to the disease out come. eg. HIV

Question 2

What are proximal causes?

Answer 2

These are the ultimate causes that leads to the disease, the trigger which established the final outcome.
Proximal causes may be superimposed on a chronic condition

Question 3

What are distal causes

Answer 3

These are chronic conditions which place the host at a predisposition to a particular disease. e.g malnutriion (distal cause) predisposes to infectious diseases (proximal cause)

Question 4

Are diseases often caused by individual factors? Expand

Answer 4

No, often a number of factors interact and lead to the final outcome. Two epidemiological models exist (the older and newer)