Self care and consumer health. Do we need a public health ethics?

ebate over whether mammogra-phy screening saves lives has become front page news again in recent months. The opening salvo came in October 2001 from Gotzsche and Olsen, who argued in the Lancet that five of the seven randomised trials of screening mammography were of poor or flawed quality and that the remaining two fail to show that the benefits outweigh the risks. 1 In the US, scientific experts remain divided in their recommendations regarding the benefits of mammography for women in their 40s, although the practice has been strongly defended by political leaders. 2 This controversy , like many in the realm of disease prevention, raises an important question: when science is uncertain, what else drives an individual investiga-tor's interpretation of the evidence? In the midst of a public debate over prevention recommendations, it often seems that even in the best of circumstances (that is, when there is a ran-domised clinical trial) there is little objective knowledge to be found. Indeed, prevention science is frequently charged with being subjective and value laden. The investigator's scientific judgment may be polluted by influences other than the evidence itself. The list of suspected polluters is long, including commitment to a favourite theory, type of training (physician , epidemiologist, biologist), personal habits (smoking, diet), concern about the financial costs of screening, and attitudes towards balancing false positives versus false negatives, to name just a few. Such influences seem to threaten traditional notions of scientific objectivity. At the start of the scientific revolution in the 17th century, the character of a scientist was believed to be as important as any experimental technique. A scientist , it was believed, should exhibit selflessness, disinterestedness, and a willingness to change her views. 3 In other words, the scientific investigator should be a neutral observer with no personal interest in their theories or results. Today, in comparison, we are somewhat jaded. No one claims that scientists can be wholly objective and impervious to outside influences, but, at the same time, few of us are willing to give up on scientific objectivity. Some epidemiologists have responded to this challenge by insisting that individual investigators try, as much as possible, to insulate their scientific work from the realm of policy making. 4 5 They urge that investigators should not be active in influencing policy when they are conducting conducting scientific research on a related topic. In other words, they should try …