What is Prevention Paradox?

Yes, it is a paradox;

“A measure that brings large benefits to the society only offers a little to each participating individual”.

This is what its proponent, Geoffrey Rose wrote in his 1981 article published in the British Medical Journal1. Arguably, experts consider the preventive paradox the best public health concept ever formulated. Rose mentioned two examples – mass vaccinations and mandatory seat belt use – to support his claim in addition to convincing several data sets in his subsequent publication2.

With the above quote, he cautions not to expect much with individual health education attempts. It is because it is not easy for us to change and maintain the new behaviour. He uses an everyday example to support his claim:

” Being a smoking doctor is uncomfortable these days for your colleagues either pity you or despise you. Not smoking may be easier. Not smoking brings immediate rewards”.

“A measure that brings large benefits to the society

offers a little to each participating individual”

Rose, G. 1981. ‘Strategy of prevention: lessons from cardiovascular disease’. 
British Medical Journal, 282, 1847-18511.

To discuss the prevention paradox, I am using Rosie’s two examples2.

An example I: More cases of heart attacks comes from those with lower risk.

Look at the following bar chart I created using data published in Rose’s paper2. He obtained this data from the UK Heart Disease Prevention Project.

As we can see in the above bar chart, as many as 32 per cent of total cases of heart attack occurred among those having risk factors alone. Those with the highest severity – those having both risk factors and ischemia – contributed only 12 per cent to the total caseload although they were at the highest risk. This is because those with the highest risk are few in number.


However, the debate on the population strategy’s utility in regard to preventing coronary heart disease has been continuing. Much later, Douglas Manuel et al.3 argued that the high-risk strategy could also be as effective as the population strategy in coronary heart disease mortality reduction3. Their arguments were based on the following concepts;

  • The coronary heart disease prevention strategies should be based on the population risk distribution; Using Canadian heart health survey y data, they argue that the risk is concentrated in a modest proportion of the population.
  • As a result, population-based strategies should evaluate first the baseline risk level of a population.
  • Risk screening methods have now improved and multiple risk factors are used.
  • Treatment guidelines are potentially as effective as population strategies.

However, the above arguments depend on the wide-scale applicability of treatment methods and adherence to medications.

Still, following Rose’s analogy is valid and irrefutable.

High-risk approach is analogus to famine relief, which feeds the hungry but does not tackle the causes of famine (p.47).

Geoffery Rose, The strategy of preventive medicine. 1992. Oxford Uni. Press.

It is more so when we acknowledge the modifiable root causes for many non-communicable diseases: Socioeconomic, and political determinants of health.


Then, Rose uses another well-illustrated example burrowing data from Alberman et al.4

Example 2: More babies with Down syndrome are born to women younger than 34 years.

Now, look at this graph, again, created by myself using data published in the same paper2.

As we can see in this bar chart, of all babies with Downs Syndrome, 71 per cent were born to mothers aged 34 or younger although the individual risk is much lower. In contrast, only 29 per cent of such babies were born to mothers aged 35 and above. In this instance, Rose convincingly demonstrates that the high-risk approach does not work here.

Later, Norman Kreitman demonstrated evidence that supports the prevention paradox in regard to alcohol-related problems.

What does this evidence mean?

Rose summarises these findings as follows:

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

Geoffrey Rose, Sick individuals and sick populations, International Journal of Epidemiology,
Volume 30, Issue 3, June 2001, Pages 427–432, https://doi.org/10.1093/ije/30.3.427,

Here, it is clear that screening for high-risk is not going to be effective in this instance; it requires a population-based approach.

As mentioned before, the population approach is not without its own problems. I mentioned some of those above in regard to the progress of high-risk screening tools such as the Framingham screening tool for coronary heart diseases.

Another critic says that the population approach can exacerbate social inequalities5.

References

  1. Rose, G. 1981. ‘Strategy of prevention: lessons from cardiovascular disease’. British Medical Journal, 282, 1847-1851
  2. Geoffrey Rose, Sick individuals and sick populations, International Journal of Epidemiology, Volume 30, Issue 3, June 2001, Pages 427–432, https://doi.org/10.1093/ije/30.3.427
  3. Manuel DG, Lim J, Tanuseputro P, Anderson GM, Alter DA, Laupacis A, Mustard CA. Revisiting Rose: strategies for reducing coronary heart disease. BMJ. 2006 Mar 18;332(7542):659-62. doi: 10.1136/bmj.332.7542.659. PMID: 16543339; PMCID: PMC1403258.
  4. Alberman E, Berry C. Prenatal diagnosis and the specialist in community medicine. Community Med 1979;1:89–96.
  5. Katherine L. Frohlich, Louise Potvin, “Transcending the Known in Public Health Practice”, American Journal of Public Health 98, no. 2 (February 1, 2008): pp. 216-221.

Author: Prasantha De Silva

A specialist in Community Medicine board-certified in Sri Lanka and a research analyst in Canada

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