Preventative Medicine (7 & 8)

Question 1

Primary prevention

Answer 1

Preventing the onset of disease - behaviour and environment (vaccine)

Question 2

Secondary prevention

Answer 2

Halt progression once started, early diagnosis, screening NB healthy people thus different

Question 3

Tertiary prevention

Answer 3

Limit disability and complications in established disease - rehabilitation

Question 4

Geoffrey Rose’s single population theory

Answer 4

• primary determinants of disease are mainly economic and social therefore its remedies must be economic and social
• medicine and politics cannot and should not be kept apart

Question 5

High risk

Answer 5

Identify and treat the ‘top end’ of the population distribution (screening in GP)

Question 6

Population approach

Answer 6

Shift the mean of the entire distribution to the left (increase exercise, reduce salt in diet, reduce obesity)

Question 7

Individual based approach

Answer 7

• Identify individuals at high risk - screening
• Intervene only in individuals at high risk
• Risk-benefit balance individually assessed

Question 8

Population based approach

Answer 8

• Identify important risk factors for the community (prevalence)
• Policy to reduce risk irrespective of individual risk
• Risk-benefit balance for whole community

Question 9

Derek Wanless

Answer 9

‘Securing our Future Health’ 2002, economic analysis showing burden of ill health on QoL in 2020

Question 10

Sensitivity =

Answer 10

True positive/(True positive + False negative)

Question 11

Specificity =

Answer 11

True negative/(False positive + True negative)

Question 12

Sensitivity

Answer 12

The proportion of people with the disease who are identified as having it by testing positive

Question 13

Specificity

Answer 13

The proportion of people without the disease who are correctly re-assured by a negative test result

Question 14

Positive predictive value

Answer 14

Probability that a person with a positive test result actually has the disease

Question 15

Negative predictive value

Answer 15

Probability that a person with a negative test result does not actually have the disease

Question 16

High sensitivity

Answer 16

• Maximise identification of diseased people in the screened population
• Relatively few false negatives
• Unnecessary investigation/treatments for others
• Lots of false positives

Question 17

High specificity

Answer 17

• Tend to detect only people with the disease
• Relatively few false positives
• Will miss people who have/at risk of disease
• Lots of false negatives

Question 18

Desire high sensitivity

Answer 18

• Adverse consequences of late treatment worse
• Adverse consequences of missed diagnosis for society
• Diagnosis confirmed by other tests/correct diagnosis before treatment

Question 19

Desire high specificity

Answer 19

• Diagnosis is associated with anxiety/stigma
• Further investigations are time-consuming, painful/expensive
• Cases are likely to be detected by others means before it’s too late
• Treatment offered without further investigation

Question 20

Lead time bias

Answer 20

Early diagnosis falsely appears to prolong survival

Question 21

Length time bias

Answer 21

Screening over-represents less aggressive disease

Question 22

Wilson and Jungner

Answer 22

10 principles and practice of screening for disease