Lecture 12 (Prevention)

Question 1

4 types of prevention:

Answer 1

• primary - before exposure
• secondary - after exposure (screening)
• tertiary - after disease process (treatment)
• quaternary - overtreatment

Question 2

Quaternary prevention:

Answer 2

• overtreatment
• treating symptoms when no disease is present

Question 3

Epidemiological transition:

Answer 3

• acute diseases decline as chronic diseases rise

Question 4

Vaccines:

Answer 4

• form of primary prevention
• herd protection = when 90% of population vaccinated
• vaccine controversy invokes:
  
  • morality and ethics
  • efficacy and necessity
  • safety
  • politics

Question 5

Screening:

Answer 5

• form of secondary prevention
• can lead to a cure if early detection and intervention
• false positive screenings (PSA) may lead to adverse events

Question 6

When you should screen:

Answer 6

Diseases with:

1. high prevalence
2. an accepted treatment
3. facilities available for care
4. latent stage
5. good screening test available (non-invasive, cheap, good specificity and sensitivity)
6. natural history of disease understood
7. cost-efficient
8. long-term screening

Question 7

Specificity of a screening test can be evaluated by:

Answer 7

• following up on a positive screen with a diagnostic test.

Question 8

Three types of screening bias:

Answer 8

1. lead-time bias
2. length-time bias
3. compliance bias

Question 9

Lead-time bias:

Answer 9

• illusion that screening is beneficial. Screening leads to earlier detection and diagnosis, therefore, they seem to live longer than people who don’t have screening and have a later diagnosis date.

Question 10

Length-time bias:

Answer 10

• slow growing cancer more likely to be detected by screening than fast growing tumors. Slow is less likely to kill, makes screening detection look better.

Question 11

Compliance bias:

Answer 11

• people who get screened generally lead healthier lives.

Question 12

Chemoprevention:

Answer 12

• Using drugs, diet, and/or dietary supplements to reduce disease.
  
  • i.e. statins, vitamin D, fish oil, fruits and vegetables, antioxidants

Question 13

United States Preventative Services Task Force: (USPSTF)

Answer 13

• non-federal
• makes recommendations for screenings and chemoprevention
• lead to Medicare initial preventative visit and yearly wellness visits
• Grade I = insufficient evidence