‘Volksgezondheids-campagnes leveren niets op’
Zoals we in een eerder bericht deze week zagen, probeert de Wereldgezondheidsorganisatie (WHO) via grootscheepse, door de farmaceutische industrie zwaar gesponsorde, campagnes de (westerse) wereld te bewegen om minder te gaan roken, minder vet te eten en meer beweging te hebben. Zij beweren daarbij dat deze maatregelen de kans op een langer en gezonder leven verhogen.
Maar is dat ook zo? Op de kwaliteitssite Techcentralstation beweert de Canadese volksgezondheidsexpert John Luik van niet: de grootschalige onderzoeken die geanalyseerd hebben of dit soort maatregelen inderdaad tot het beoogde doel leiden laten meestal zien dat het weinig uitmaakt of dat het zelfs soms nadelig werkt.
“The health promoter will claim that it is a scientific fact that if you stop eating fast foods you will live longer. (This is likely not true, but let’s suppose it is.) Therefore you should stop eating fast foods. But this argument only works if another premise, a distinctly non-scientific premise is added, namely, IF you value living longer more than you value eating fast foods, then you should stop eating fast foods.”
The first of these is that health promotion accepts if not encourages the manipulation and misrepresentation of scientific findings about the connection between health and lifestyle. Health promotion claims that by massive interventions by the public health community and the government into the “lifestyles” of ordinary people, the major diseases of the old in affluent societies can be prevented. As Gina Kolata, writing in the NY Times (April 17, 2005) observed. “The promises are everywhere. Sure, you smoked. But you can erase all those years of abusing your lungs if you just throw away the cigarettes. Eating a lot of junk food? Change your diet, lose even 5 or 10 pounds and rid yourself of those extra risks of heart disease and diabetes.” But is this in fact true? Is there a scientific basis for the basic claim of health promotion that, for example, the two leading causes of death — cancer and heart disease — are the products of unhealthy lifestyles and that changing these lifestyles can prevent these diseases? Or are the promises of lifestyle change based on nothing more than hype?
The answer, which many will find surprising, is that after over fifty years of international data there is not good scientific support for the claim that lifestyle changes prevent diseases or increase longevity. Take, for example, one of the most extensive and publicized efforts in health promotion of all time, the Mr Fit (Multiple Risk Factor Intervention Trial) which was specifically designed to establish the truth of health promotion by showing that heart disease and cancer could be reduced through reducing blood pressure, cholesterol, and smoking. After sixteen years of study, the intervention groups, which had received extensive assistance with exercise, changing diet and smoking cessation, had results which were not significantly better than the group that had received none of these “health promotion” interventions. Indeed, the intervention group, despite lower rates of smoking, actually had higher rates of lung cancer. What MR Fit showed was precisely how lifestyle interventions failed to reduce mortality from multifactoral diseases like cancer and heart disease.
Nor was Mr Fit a scientific fluke. Consider the Framingham study. Begun in 1950 as a longitudinal investigation of the causes of cardiovascular disease, some 5,209 men and women aged 30-59 were followed for 30 years on the assumption that those who were thinnest would have significantly lower risks for heart disease. But in 1979 when three of the study’s lead researchers published their data it was found that for men the highest risk — that is the worst life expectancy — was for the thinnest men; men who were 25-40% fatter than the ideal weight were living the longest. For women, mortality was elevated only for the very thin and the very fat. The recent Centers for Disease Control study on obesity and mortality produced similar results.
The reason for this lack of scientific support for lifestyle changes is to be found in the nature of the diseases about which we are speaking, and the fact that we know so little about them and how they might be connected with some particular aspect of how we live our lives. Both heart disease and cancer are multifactoral diseases, generally of old age, diseases that have multiple causes. For example, heart disease alone has over 300 risk factors that can be linked to lifestyle in thousands of possible combinations, while the etiology of cancer remains a mystery. To assume then that we can confidently tell people what life-style modifications can “prevent” cancer or heart disease is something much closer to propaganda than careful science. As Dr. Barnett Kramer of the National Institutes of Health told Kolata, people believe that if they change their lifestyle they can eliminate the damage and cheat disease because of the health promotion messages from the public health community and the government. “It is easy to overestimate based on the strength of the messages. But we’re not as confident as the messages state.”
At its very core, health promotion is a menace to legitimate science since it is prepared to fudge, force or fix whatever science says in order that it might serve the ends of promoting health. If you think this is too extreme a description of how health promotion views its relationship to science simply listen to Marc Lalonde, a former Canadian Minister of Health and founder of the health promotion movement, speaking about the relationship of health promotion and science. “…[T]he spirit of enquiry and scepticism, and particularly the Scientific Method… are a problem in health promotion.” It’s somewhat worrisome that the world’s primary health organization, WHO, has embraced a health strategy for which science is a problem.