Health Prevention

Question 1

What are the categories of prevention?

Answer 1

1. ) Primary: Preventing the onset of the disease- behavior and engagement
2. ) Secondary: Halt progression once started- early diagnosis, screening
3. ) Tertiary: Limit disability and complications in established disease- rehabilitation

Question 2

What are the different approaches to health prevention?

Answer 2

Using hypertenion as an example:

• High risk: Identify and treat the “top end” of population distribution- case finding/screening in general practice
• Population approach: shift the mean of the entire distribution to the left (increase overall population health) by increased exercise, reduced salt in diet, reducing obesity

Question 3

What is the prevention paradox?

Answer 3

Immunisation- benefits population as a whole.

Individual point of view: the chance of benefit can be outweighed by the certainty of pain and reaction form the vaccination

Question 4

Are causes of population incidence the same as causes for individual cases?

Answer 4

No

Question 5

Can a large number of people with a small risk of disease give rise to more cases that a small number of people at high risk?

Answer 5

Yes it may do

Question 6

Screening as an example of secondary protection:
What is sensitivity?
What is specificity?
What is the positive prediction value?
What is the negative prediction value?

Answer 6

A=true +ve (have disease) B=false+ve (don’t have disease) C=false-ve (have disease) D=true-ve (don’t have disease)

Sensitivity is the proportion of people with the disease who are identified as having it by a positive result. A/(A+C)

Specificity is the proportion of people without the disease who are correctly reassured by a negative test result. D/(D+B)

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

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

Question 7

High sensitivity vs High specificity

Answer 7

High sensitivity maximizes the identification of disease people in the screened population. It has few false negatives, but lots of false positives. Can mean unnecessary investigations and treatments. Used if missed diagnosis would mean adverse consequences for the individual (late treatment not effective) or society (communicable disease) or if the diagnosis is to be confirmed by other tests before treatment is started- so short period of anxiety for the patient

High specificity only detects those with the disease, can miss some with the disease and those at risk. It has few false positives but lots of false negatives. Used if the diagnosis is associated with anxiety or stigma, further investigations are time consuming, painful or expensive, cases are likely to be detected by other means before it is too late for effective treatment or treatment is going to be offered without further investigations

Question 8

What is lead time bias and length time bias?

Answer 8

Lead time bias: Early diagnosis falsely appears to prolong survival
Length time bias: Screening over-represents less aggressive disease

Question 9

Drugs and alcohol Misuse:
What are the effects on health?
What are the costs to society?

Answer 9

The effects on health are multiplicative, not just addictive

The cost to society are multiplicative: Cost of healthcare, losses to economic productivity, social costs

Question 10

What are examples of class A drugs? What are the punishments for possession and supply?

Answer 10

Class A: Heroin, ecstasy, amphetamines prepared for injection, crack cocaine, magic mushrooms.
Possession: Up to 7 years in prison or an unlimited fine or both
Supply: Up to life in prison or an unlimited fine or both

Question 11

What are examples of class B drugs? What are the punishments for possession and supply?

Answer 11

Class B: Amphetamines, methamphetamines, barbiturates, codeine, cannabis
Possession: Up to 5 years in prison or an unlimited fine or both
Supply: 14 years

Question 12

What are examples of class C drugs? What are the punishments for possession and supply?

Answer 12

Class C: Temazepan, anabolic steroids, valium, ketamine, Ritalin, GHB
Possession: 2 years
Supply: 14 years

Question 13

What did the Derek Wanless report find?

Answer 13

Linked health to economic benefit. NHS should focus on keeping people healthy rather than treating disease

Question 14

What are Wilsons and Jangler’s principles for screening?

Answer 14

• The condition should be an important health problem
• The test should be a simple, safe, precise and validated screening test
• The treatment should be effective if the condition is detected early
• The screening programme: There should be evidence from randomised control trials that it is effective