Twenty years since Ottawa and Epp: researchers' reflections on challenges, gains and future prospects for reducing health inequities in Canada.

November 2006 marked the 20-year anniversary of the Ottawa Charter for Health Promotion and Canada's Epp Report. Encapsulating the tenets of health promotion (HP), these publications articulated a vision for reducing health inequities, and described a policy framework for achieving this vision, respectively. These documents also triggered the launch of the population health (PH) field, focused on elucidating the empirical relationships between socioeconomic gradients and population health inequities. Over two decades, a rich HP/PH theoretical and evidentiary base on socioeconomic gradients in health has established. Yet, despite valuable contributions from Canadian researchers, insufficient headway has been made in this country to achieve the Charter's vision. There are numerous challenges to reducing population health inequities in Canada. Informational challenges include complexity of HP/PH evidence, and inadequate knowledge translation beyond traditional targets. Institutional challenges include the relative immunity of the healthcare sector to funding reductions, and the organization of policy responsibilities into silos. Concerns from non-healthcare sectors of 'health imperialism', and inter-governmental tensions are interest-related challenges, while ideological challenges include lack of media discourse on health inequities and a strong neo-liberal political climate. Gains have been made in Canada towards reducing health inequities. The HP/PH discourses are firmly entrenched in academic and policy spheres across the country, while several inter-sectoral policy initiatives are currently underway. HP/PH researchers could be more proactive in the knowledge-translation sphere by engaging other researchers outside of medicine and health, non-healthcare policy-makers, and the general public, vis-à-vis the media, on the health inequities knowledge base. Ultimately, significant and sustained progress will only be made if researchers and other champions recognize the inherently political aspect of their work and understand how to overcome ideologically driven resistance.