A lot more can be done to prevent cardiovascular diseases

Erkki Vartiainen

Department of Epidemiology and Health Promotion, National Public health Institute, Helsinki, Finland

E-mail address: erkki.vartiainen{at}ktl.fi

This editorial refers to "Evaluating the impact of population and high-risk strategies for the primary prevention of cardiovascular disease"1 by Emberson et al. on page 484

The potential to prevent cardiovascular diseases is still seriously underused in most countries. Present analyses show that mortality from cardiovascular diseases can be reduced by 59% by reducing mean blood pressure and serum cholesterol 15%. Treating those who are in a 30% risk of getting a cardiovascular disease in the next 10 year by statins, ß-blockers, ACE-inhibitors and aspirin at the same time should reduce mortality only by 11%.1 This is based on the simple fact that the effect of risk factors on mortality continues without any natural threshold limit and most of the cases come from the moderate risk factor level where the majority of population is. This concept was developed in the late 1960s and early 1970s when the first community based cardiovascular diseases prevention programmes were started in Stanford Three City Study and in North Karelia in Finland.2 At that time there were two main questions: Can the risk factors be reduced on a population level and if the risk factors reduce will the mortality also be reduced? Today we can answer positively to both of those questions. In North Karelia cholesterol levels have reduced 18% both in men and women and blood pressure 8% in men and 13% in women from 1972 to 1997.3 Mortality has followed risk factor changes, as can be expected, based on estimates both form cohort studies and clinical trials.4 Analyses from Scotland5 and New Zealand6 give similar results: just over half of the mortality decline was explained by risk factor changes. We should not see the population and high risk strategies as alternatives but approaches that support each others.

In the present analyses the high risk strategy is based entirely on drug therapy which of course is not the case in real life. When considering a large scale drug treatment with multiple drugs we have to take into account the cost and possible side effects of the drugs. It is ironic that western cultures have developed diets that causes coronary heart disease and then developed drugs to correct the high cholesterol or blood pressure level that results. Much of the high risk strategy can be done by dietary and other life style changes.7 Although it is very important to reduce the risk level of those people who are in very high risk to get coronary heart disease or stroke it will in any case have only a limited effect on mortality on the population level.

There has been criticism on the possibilities of the population approach. There seem to be two main reasons for that: Firstly, many people feel that prevention has failed. This is not the case. In fact there are many countries which has been very successful in prevention like the US, Australia, New Zealand and UK. On the other hand mortality from cardiovascular diseases increases in many developing countries and is becoming a major public health problem. The second concern has been the limited but existing evidence of the effectiveness of community based programmes compared with clinical drug trials among high risk people. The usefulness of trial designs in population based studies is limited. Increasing the number of communities in the trial will reduce the intensity of interventions which is a main problem in community based studies. Secondly, in the population approach we have to change the society. It is unlikely that the development in one part of the country can be very different from the rest for a longer period of time. In North Karelia the reductions of risk factors were faster during the first five year period but after that the development has been about the same in the reference area and also in other parts of the country.

The analyses clearly show that medical community should pay more attention to reduction of average risk factor level in the population in addition to treating those with very high personal risk.

Footnotes

1 doi:10.1016/j.ehj.2003.11.012. Back

References

  1. Emberson J, Whincup P, Morris R et al. Evaluating the impact of population and high-risk strategies for the primary prevention of cardiovascular disease. Eur. Heart J. 2004;25:484–491.[Abstract/Free Full Text]
  2. Puska P, Tuomilehto J, Nissinen A et al. The North Karelia project: 20 year results and experiences. Helsinki: National Public Health Institute, University Printing House; 1995. .
  3. Vartiainen E, Jousilahti P, Alfthan G et al. Cardiovascular risk factor changes in Finland, 1972–1997. Int. J. Epidemiol. 2000;29:49–56.[Abstract/Free Full Text]
  4. Vartiainen E, Puska P, Pekkanen J et al. Changes in risk factors explain changes in mortality from ischaemic heart disease in Finland. BMJ. 1994;309:23–27.[Abstract/Free Full Text]
  5. Capewell S, Morrison CE, McMurray JJ. Contribution of modern cardiovascular treatment and risk factor changes to the decline in coronary heart disease mortality in Scotland between 1975 and 1994. Heart. 1999;81:380–386.[Abstract/Free Full Text]
  6. Capewell S, Beaglehole R, Seddon M et al. Explaining the decline in Coronary Heart Disease Mortality in Auckland, New Zealand between 1982 and 1993. Circulation. 2000;102:1511–1516.[Abstract/Free Full Text]
  7. Jousilahti P, Vartiainen E, Pekkanen J et al. Serum cholesterol distribution and coronary heart disease risk. Observations and predictions among middle-aged population in Eastern Finland. Circulation. 1998;97:1087–1094.[Abstract/Free Full Text]

Related articles in EHJ:

Evaluating the impact of population and high-risk strategies for the primary prevention of cardiovascular disease
Jonathan Emberson, Peter Whincup, Richard Morris, Mary Walker, and Shah Ebrahim
EHJ 2004 25: 484-491. [Abstract] [Full Text]  




This Article
Full Text (PDF)
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Related articles in EHJ
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Request Permissions
Google Scholar
Articles by Vartiainen, E.
PubMed
PubMed Citation
Articles by Vartiainen, E.