Question 1

When attempting to predict or model the future benefits that might accrue from an effective preventive intervention, should the reference category for the causal agent
Of interest, e.g.sun exposure or cigarettes, (i.e.the level of exposure to which the
Intervention aims to shift the population) be:

Accepted Answer

Each of these could be reasonable, depending on the exposure in question‐
not a straightforward task, one that requires a lot of thought and detailed subject
matter knowledge.

Question 2

Which of the following actions is not an example of primary prevention?

Accepted Answer

This is what is sometimes referred to as tertiary prevention, but is probably
better seen as supportive treatment to minimise the harms of the stroke.The others
show some of the range of actions - personal, medical and legislative in these instances
- that can constitute attempts to prevent disease occurring in the first place.Although
the patient in B already has high blood pressure, they are treated to prevent them from
developing more serious disease in the future.

Question 3

The multi‐drug polypill to reduce primary and secondary cardiovascular events (CHD and stroke), is mentioned in the text as a possible simple, safe and cheap preventive.
Early trials suggest it can improve compliance in patients already taking a number of
Its component drugs separately; and it is expected there will be results within a year
On whether it is effective in reducing blood pressure and serum cholesterol.It will
Take further years of follow‐up before definitive data on whether it reduces
Cardiovascular morbidity and mortality are available.Choose the best policy to
Implement now from among the following options:

Accepted Answer

If the principle preventive aim is to put people who do not have clinical
disease onto long term drug therapy (and it is), then we have to be able to tell them
clearly what the likely benefits to them are going to be in quantitative terms, i.e.how
much their risk of having a heart attack or stroke, and of dying from either, will be
reduced by taking the polypill.A case might be made for A (on the basis of simplifying a
drug‐taking regimen, and increasing compliance), although it makes it impossible for
the drug doses to be changed, making on‐going treatment tricky to manage.

Question 4

A 'high risk' strategy for prevention:

Accepted Answer

It is entirely appropriate in some situations (A) and in these situations may
have a good benefit:cost ratio (B), it is also often easier to 'sell' (E) because it is directed
as those for whom it is most relevant.While a mixed programme of high risk and wider
population strategies (C) can be a good combination, it is not a necessary one.

Question 5

Which one of the following options offers the best approach to controlling a chronic disease?

Accepted Answer

We lack the knowledge and/or intervention tools to prevent all major
diseases, so A alone is insufficient.The most comprehensive approach to disease
control demands a judicious balance of primary prevention and optimal clinical care.
Clearly this balance will differ among populations with different disease profiles, and
with changing knowledge as new preventives and new treatments are shown to be
effective in research settings.

Question 6

The Minister for Health has announced that an additional $5 million will be provided to strengthen mental health treatments and services to prevent attempted suicide in
The population.You have collected some data on mental disorders and attempted
Suicide in this population (presented in the table below), and you are asked by the
Minister to recommend which disorder should be targeted to ensure the biggest
Impact on the burden of attempted suicide in the population.Which mental disorder
Do you recommend?

Accepted Answer

Substance use disorder is the most likely candidate, as it has the largest
population attributable fraction (24.2%).This suggests that almost a quarter of
attempted suicide cases could be prevented if Substance use disorder were to
disappear from the population.Substance use disorder does not have the strongest
association with attempted suicide - psychosis has a RR three times greater - but it is
much more common than psychosis (10% vs.1%), and this drives the high proportion of
cases associated with it.
Of course, in practice it is unlikely that a single disorder would be targeted for a single
outcome, and it might be that each of these disorders (and other determinants of
attempted suicide) would also be targeted in a strategy combining a number of
approaches.

Question 7

Which of the following data sources do you think would provide the best data to evaluate how well a national primary prevention programme of behavioural change
To decrease the mortality rate from a cancer is working?

Accepted Answer

These data directly address the aim of the programme (have mortality rates
fallen?), but if other control measures (e.g.a new treatment) have also been introduced
it can be difficult to determine the specific contribution of the prevention programme
per se.E gives a direct measure of the effect of primary prevention on the occurrence
of new disease, so a better judgement can be made by looking at time trends in both
mortality and incidence; if the former parallels the latter after an appropriate lag time
(the average survival time post‐diagnosis) then the mortality decrease may well be
largely due to the prevention strategy.B can be a useful process measure of whether
there is good uptake of the behavioural change - if there is no or minimal change then
there is little basis for continuing; but showing behaviours have changed (if that is what
is found) is not enough to declare the programme a success until disease and mortality
rates drop.In the context of a national programme, it would not be ethical to conduct a
randomised trial (C) and a cohort study (A) would almost certainly be subject to
confounding because those who changed their behaviour would almost certainly differ
in other ways from those who did not change (i.e.the groups would not be
exchangeable).
Note - in practice this decision might not be straightforward.For a more complex
situation see e.g.Knox, K.L., Pflanz, S., Talcott, G.W., Campise, R.L., Lavigne, J.E., Bajorska,
A., Tu X., Caine, E.D.(2010).The US air force suicide prevention program: Implications for
public health policy.American Journal of Public Health, 100: 2457‐2463.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2978162/

Question 8

Campaigns to lower smoking rates and advances in medical and surgical therapies have both helped bring about large declines in mortality from coronary heart disease
(CHD) in Canadian men.Which of the following study designs and epidemiological
Measures could contribute to assessing their relative contributions?

Accepted Answer

None of these options can answer the question on its own but most central
are (A) because if treatments have improved (e.g.surgical stenting) then people should
now be less likely to die from their CHD (i.e.the case‐fatality ratio should be lower) and
(B) because if smoking cessation campaigns have had an effect there should be a
measurable decline in CHD incidence as a result (and this would be apparent much
more quickly than for lung cancer).Although, at a practical level, we must remember
that comparisons across different cohorts of patients challenge the assumptions we are
necessarily making about exchangeability, and CHD incidence data are mostly not
available.The other measures will confirm the extent to which smoking rates have
fallen (C) and/or that GPs are now identifying and treating more people with high blood
pressure (D) which, when combined with information about changing incidence rates,
can help demonstrate that the changes have occurred in parallel.

Quiz 14: Prevention: Better Than Cure

When attempting to predict or model the future benefits that might accrue from an effective preventive intervention, should the reference category for the causal agent Of interest, e.g.sun exposure or cigarettes, (i.e.the level of exposure to which the Intervention aims to shift the population) be:

Which of the following actions is not an example of primary prevention?

A 'high risk' strategy for prevention:

Which one of the following options offers the best approach to controlling a chronic disease?

Which of the following data sources do you think would provide the best data to evaluate how well a national primary prevention programme of behavioural change To decrease the mortality rate from a cancer is working?