Epidemiology/prevention/stats

Question 1

Three things that must be fulfilled for a factor to be confounding:

Answer 1

Must be associated with the exposure
Associated with the disease independent of the exposure
Must not be an intermediate between the exposure and pathway of disease

Question 2

What is an ecologic study?

Answer 2

Uses the groups of people as the unit eg dietary fat intake and incidence of cancer by country

Question 3

Th accuracy of a test in predicting the presence of disease

Answer 3

The positive predictive value

The probability that people with the disease truly have the disease

Question 4

Sensitivity

Answer 4

True positives out of all those with the disease
True positive rate
Sensitivity = true positive /(true positives and false neg)

Question 5

Specificity

Answer 5

If a person does not have the disease how often will the test be negative
Specificity= true negatives/(true negatives + false positives)

Question 6

Negative predictive value

Answer 6

Accuracy of test in predicting the absence of disease

Question 7

How to calculate positive predictive value?

Answer 7

PPV= true positives/ all positives

Question 8

Who is MRI breast screening indicated for?

Answer 8

Women at very high risk of breast cancer

Question 9

H pylori increases rates of which malignancy?

Answer 9

Intestinal type gastric adenocarcinoma

it’s actually protective against oesophageal adenocarcinoma and gastric cardia carcinoma!