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In the <?xml:namespace prefix = st1 ns = “urn:schemas-microsoft-com:office:smarttags” />United Kingdom, the Sir John Krebs, Chairman of the Food Standards Agency (FSA), has just announced that the agency will take steps to combat the growing menace of advertising promoting unhealthy diets to children. The trouble is that the FSA itself has admitted there is no evidence of a problem. It seems that in the UK, politics drives science. There is evidence that the same is happening over here in the US on both sides of the political divide. These problems could be solved by adherence to some simple rules of sound science.
Sir John Krebs said on 11 March, “Children are bombarded with messages that promote food high in fat, salt, and sugar. The evidence shows that these messages do influence children. Eating too much of these foods is storing up health problems for their future. The Food Standards Agency wants healthier choices to be promoted to children.” Yet less than two months ago, one of Sir John's chief Deputies gave the UK House of Commons Health Committee completely the opposite assessment of the state of the science. Mrs. Rosemary Hignett, Head of the FSA's Food Labeling Standards Division, told the MPs, “Most of the work that has been done has been around TV advertising. We did ask the reviewers to look at the issue of the size of the influence of TV advertising as against other influences, both other promotional activities and also other influences on behavior. The conclusion which the researchers drew was that the evidence is not there to draw any conclusions on the magnitude of the effect.”
As Britain's Social Issues Research Centre pointed out, “In what we take to be proper science-based approaches, if the magnitude of an effect cannot be measured then it cannot be said to exist at all.” Sir John has clearly taken a political decision to proceed with restrictions on advertising despite the fact that the evidence does not point him down that road at all. An approach to regulation based on the principles of sound science (specifically, that research must identify that a practice has a statistically significant effect before action can be taken on it) would not allow the FSA to take such a step. Politicians and political appointees like Sir John are, perhaps naturally, only too willing to use science as stolen lightning to justify their decisions. Sound science rules help to protect the integrity of science from the manipulation of politicians.
Two interesting examples from the USA may serve to underline this point. The Bush administration has come under repeated attack for its use of scientific research. Much of this assault is politically inspired itself and too reliant on anecdote and insinuation to carry much weight, but in some cases sound science rules do seem to have been breached. For example, in November 2002 the National Cancer Institute (NCI) changed its advice on the postulated link between abortion and breast cancer to say, “Some studies have reported statistically significant evidence of an increased risk of breast cancer in women who have had abortions, while others have merely suggested an increased risk. Other studies have found no increase in risk among women who have had an interrupted pregnancy.” This created a furor among epidemiologists, who generally consider that abortion should not be considered a significant risk factor for breast cancer (except in some very specific cases). As a result, the NCI convened a conference, after which it restated the advice in 2003 as saying that it was “well-established” that, “Induced abortion is not associated with an increase in breast cancer risk.”
The whole farrago could have been avoided if a simple rule of sound science had been followed. Epidemiologists generally agree that one cannot ascribe medical causation to a risk factor if the factor is associated with less than double the occurrence than normal. This means that, for abortion to be regarded as a significant risk factor for breast cancer, the rate of breast cancer in women who have had abortions needs to be double the rate than in the general population. If it doesn't reach that level, there is too big a chance that confounding factors may be the explanation, not the abortion (are women who are likely to get breast cancer also likely to have an abortion, for instance?). The studies the NCI referred to in 2002 found around a 50 percent increase in breast cancer among women who have had an abortion. The effect was statistically significant, but it still probably was not clinically significant. The administration's change in its advice was unlikely to have been driven by respect for sound science.
However, the lack of respect for such epidemiological principle is not confined to the current administration. Examples abound across the country of jurisdictions advancing “scientific evidence” to back their impositions of smoking bans. Yet the best scientific evidence for the effects of environmental tobacco smoke, or passive smoking, suggest that it has a low relative risk. In other words, “passive smokers” aren't significantly more likely to develop smoking-related cancers than the general population. The International Agency on Research on Cancer, for example, found environmental tobacco was associated with a non-significant 17 percent increase in risk. Other studies have found only a 25 percent increased risk. In other words, the case for passive smoking causing lung cancer is weaker than the case that abortion causes breast cancer.
Of course, there is no real reason to be worried about either issue. Sound science rules tell us that there is no need for action on either front, just as Sir John's own evidence tells us that there is no need to restrict television advertising of food to children. Yet Sir John and politicians everywhere are all too happy to ignore sound science when it suits their purpose. Sound science could stand as a check and balance on the abuse of executive power, if only we'd let it.