Lecture #27 - Prevention

Question 1

The definition of Epi is “the study of the distributions and determinants of health-related states or events in specified populations and the applications of their study to the control of health problems”

This definition covers what kind of idea?

Answer 1

That the information you discover will be useful for controlling health problems - this is why studies are done. Public health is basically revolved around ‘prevention’

Question 2

Public health definition: “Science and art of preventing disease, prolonging life and promoting health through the organised efforts of society”

How does this relate to epidemiology?

Answer 2

The basic science is epi but this is more broad

Question 3

The underlying concept of prevention is?

Answer 3

We need to treat the problems overall rather than when they appear

Question 4

Levels of prevention:

1. Primordial - what is it?
2. Primary - what is it?
3. Secondary - what is it?
4. Tertiary - what is it?

Answer 4

1. Primordial = Establish and maintain conditions that minimise harm to health
2. Primary = Limit the incidence of disease by controlling causes and risk factors (modifiable)
   - “Primary – to prevent new cases of disease from occurring (reduce incidence rates) by controlling the causes and risk factors of the disease (e.g. smoke free legislation)”
3. Secondary = Reducing the prevalence of disease by shortening its duration, severity or recurrence (part of the endeavour to reduce health harm - the burden that disease carries isn’t just about whether you have it - it’s about how much it affects your life)
   - “Secondary – to improve outcomes (cure or reduce severity, reduce morbidity and mortality) in people who have already developed the disease through earlier diagnosis and treatment (e.g. cancer screening)”
4. Tertiary = Reduce the number or impact of complications; improve rehab (sounds like treatment but also influenced by stiff like if facilities are available in community and access to them)
   - “Tertiary – to reduce the impact of the consequences of a well-established disease (e.g. stroke rehabilitation programmes to improve a person’s quality of life)”

• Public health practice is principally aimed at primary prevention and addressing the social determinants of health. The goal of primary prevention efforts is to prevent disease from occurring.
• Secondary and tertiary prevention involve managing and treating established disease, and require substantial input from clinical health professionals. Although the disease is already established, the goal is to prevent or limit the more severe/debilitating consequences of the disease.

Question 5

In the example of HIV - how can you illustrate the primordial, primary, secondary and tertiary problems?

Answer 5

Primordial would be like attaining the state we had when we had no HIV in population however that’s achieved is primordial

Primary would be like effort around condom use etc - to prevent the HIV in primary site bc no one wants to be infected

Secondary was skipped but it’s about treatment but also about structural change to decrease health burden of disease in whole population (not just rich parts etc)

Tertiary (reduce impact of disease) prevention was referred to AIDs rather than HIV - jus try to make life better for those who are going to die (if couldn’t prevent it with primary then make remaining life better with tertiary)

Nowadays, they have developed drugs for treating HIV and offering them to the ones at higher risk of contracting it. It’s taken the secondary interventions to primary and stop people getting infected in the first place`

Question 6

Cardiovascular disease:

1. Briefly what is it? (FYI)
2. Why measure it as a rate and has the morality of IHD decreased in NZ and due to what?

Answer 6

1. A group of heart and blood vessel disorders and it’s a leading cause of death + disability worldwide particularly myocardial infarction and stroke
2. Because population number going up - absolute numbers aren’t decreasing but the rates are. Mortality of IHD in NZ had decreased 40% due to treatments (secondary and tertiary) and 60% because we decreased risk factors (primary prevention)

Question 7

Traffic mortality:

1. There is an active public health approach to prevent these deaths - what did they express the numbers as?
2. Any improvements?

Answer 7

1. In terms of distance travelled bc don’t have car crashes if not travelling
2. The fatalities have decreased ssince 1970s and concluded that 45% of reduction was attributed to improvement in vehicle safety, 19% bc better roads and the rest are break testing etc

Question 8

Primordial prevention:

1. Applies to underlying……
2. Aims to…..
3. Uses public policy and health promotion to…….
4. Give exams in terms of car crash and CVD

Answer 8

1. ….economical, social and environmental conditions leading to causation (change in environment so less reasons to be unhealthy
2. Aims to establish and maintain conditions that minimise hazards to health
3. Uses public policy and health promotion to minimise risk to health and inhibit emergency of problems
4. Car crash = provision of good public transport and infrastructure for cycling (in developing countries, already establishing good infrastructure because cars become prevalent is an e.g. of primordial)
   CVD = public policies that facility healthy food being affordable for everyone (trying to keep environment safe)

Question 9

Primary prevention

1. Limit the…..
2. Decreasing ____ _____ in whole population or selected groups
3. E.g.
4. Some of these interventions are…..
5. Give some examples of primary prevention for car crashes and CVD

Answer 9

1. Limit the incidence of disease by controlling specific causal factors
2. Decreasing risk factors in whole population or selected groups (if more appropriate in selected groups)
3. E.g. conditions for HIV prevention in MSM or sleeping babies on their backs to prevent SIDs or immunisation to prevent measles
4. …..passive e.g. median barriers on roads - no one has to do anything but they’ll protect you whether you want it or not
5. Car crash = low legal BAC limit, seat belt law, median barriers, random breath testes
   CVD: education and persuasion to exercise more and eat less fat or smoking cessation programmes

Question 10

Secondary prevention:

1. Reduce prevalence of disease by…..
2. Cure or stop…..
3. May involve early……
4. E.g.s in terms of car crash and CVD

Answer 10

1. shortening the duration, severity or recurrence
2. Cure or stop progression once condition has been initiated
3. May involve early diagnosis and treatment e.g. weight loss programmes or cervical screening (detect early before too late)
4. Car crash = good emergency services, license suspensions after at-fault injury crash
   CVD = treatment of BP, lips, clotting etc

Question 11

Tertiary prevention:

1. Reduce the number or……
2. Example in terms of car crash or CVD

Answer 11

1. ….impact of complications; improve rehab in clear chronic situations e.g. stroke care or diabetes treatment (it’s not just about providing treatment - it’s about having well-organised specialist services based on practise models. Improving on what would normally be in primary and secondary care to something much more effective)
2. Car crash = assistance with getting back to work
   CVD = exactly the same
   -same for both because if you survive your heart attack/car crash - what matters is how close you can get to providing quality of life and work is an important part of that

Question 12

PAR:

1. What is it?
2. How does this link in with the example of car crashes

Answer 12

1. Prop of disease occurring in pop that could be attributed to specific exposure. Basically the prop of disease in pop that wouldn’t have arisen had there not been the exposure. It’s important when considering interventions - where are getting the biggest gains? But, is it modifiable?
2. Go read top of page 53

Question 13

Strategies for primary prevention:

1. Can focus on what two things?
2. Example of both in car and CVD
3. Advantages +disadv of population strategy?
4. Adv + disadv of individual?

Answer 13

1. Individual (identified as high risk individuals)
   - Population (or sector of population) - affect whole population so more radical
2. Car crash injuries:
   -low legal BAC limit
   -random breath testing
   -improve engineering of roads
   = all this is population based (each person isn’t getting a benefit but as a whole the road toll is decreasing)
   -license suspension for speeding
   =high risk individual (already shown they speed and likely to do it again)

CVD:
-guidelines for reduction of CVD by clinicians
= can be both pop and individual

3. Pop strategy:
   -radical (enormous potential to change what’s going on in pop)
   -large potential for whole pop (increase price, people drink less)
   -behaviourally appropriate (won’t be singled out at pub if everyone has to pay higher price)
   = advantages

-small benefit to individuals (reducing drinking for low risk individuals not v important)
-poor motivation of subject
-benefit-to-risk ratio may be low (risk is usually a loss in autonomy than a physical health risk)
= disadvantages

4. High risk individuals
   -appropriate to individual (doc gives advice on how to improve you -not generic)
   -subject motivation
   -clinician motivation
   -favourable benefit-to-risk ratio
   =advantages

-need to identify individual
-temporary effect (compliance to medication - motication reduced overtime)
-limited effect
-behavoirally inappropriate (only you aren’t allowed to drink at pub)
=disadvantages

Question 14

Prevention paradox

1. What is it?

Answer 14

“A large number of ppl at small risk may give rise to more cases of disease than the small number who are at high risk”

-a preventative measure that brings large benefit to the community may offer little to each participating individual (so get opposition to regulation and being asked to change things)

Question 15

Healthy public policy (to make pop based change and healthy choice, easy choice)

1. Not just….
2. Health promoting public policy outside of……
3. Epidimiolgy must influce public policiy in order to….
4. The importance of broad public policy for health recognised in…..

Answer 15

1. ….health policy
2. …..the health sector (e.g. could be transport)
3. ……to fulfil its potential for prevention and control of health problems else won’t get very far with prevention
4. …….discipline of health promotion (public policy and education and motivation is public - part of discipline)

Question 16

What are the key advantages of mass (population) approaches over high-risk (individual) prevention strategies?

Answer 16

A mass strategy aims to reduce the health risks of an entire population, and will therefore affect the largest number of people and result in the largest absolute decreases in the targeted health outcome. The mass approach may also be effective at changing social-cultural norms and patterns that facilitate the occurrence of poor health outcomes (e.g. making a ‘binge drinking’ culture less socially acceptable). This type of strategy also avoids potential problems that may occur when particular groups or individuals within a population are singled out for specialised interventions (e.g. stigmatisation, discrimination).

Question 17

In what circumstances are high-risk strategies a good choice?

Answer 17

A high-risk strategy might be a good choice when the intervention is designed to target a particular well-defined disadvantaged group (e.g. school breakfasts and lunches for children attending low decile schools). High-risk approaches may also be appropriate when the intervention is well matched to the affected individuals and their concerns (e.g. a condom distribution programme for sex workers), and this may improve the benefit-to-risk and benefit-to-cost ratios. There are also situations when a mass approach may not be politically or socially feasible (e.g. increasing taxes on foods with added sugars), so a targeted strategy may be more acceptable. As well, high-risk strategies are easily understood by clinicians and can be readily accommodated within the existing medical system.