1226 commodified into profit making solutions; or where there is already overwhelming community support for implementing change, publicity rather than advocacy may be all that is required. Our emerging understanding of risk reduction in sudden infant death syndrome16 and of ways of reducing hip fracture in the aged and of folate in preventing neural tube defects17 are good examples of red carpet receptions being given to epidemiology. Advocacy seeks to change upstream factors like laws, regulations, policies and institutional practices, prices, and product standards that influence the personal health choices of often millions of individuals and the environments in which these are made. Advocacy shares strategies with public relations, but differs in that it invariably involves contested definitions of what is at issue. Advocates therefore often find themselves engaged in public conflict with sometimes powerful interest groups or governments determined to resist change. For the faint hearted, advocacy can take on the spectre of a fraught, politicized activity, threatening to make enemies particularly of retributive government figures and litigious industries. I have even received death threats over my gun control advocacy. This can seem a far cry from the mannered and often inconsequential exchanges in letters pages of journals.

In the space available, I will examine three recurrent concerns about public health advocacy which seem to inhibit greater engagement by those in public health and epidemiology. The first of these is the often heated debate about when state regulation of the liberty of individuals is justified. While the Millean principle of preventing harm to others18 provides broad guidance in obvious examples like arguing the case for road rules and food safety laws, the principle is often contested by interest groups disputing the evidence on harm and/or the assumed primacy of health concerns over other values. This is particularly the case of interventions where Rose’s prevention paradox applies (little benefit to individuals, but predicted benefits to whole populations). 19 I will consider this problem through two case studies that illustrate different nuances: efforts to advance legislative reforms in gun control and reduce motor vehicle injury.