Abstract
It is scientifically established that prevention, a source of health, well-being and equity, must be at the heart of health policies. The National Health Strategy has made this its first priority. 1 Expectations of prevention research are therefore growing and raise many challenges. While several types of cancer have risk factors which are supported with strong evidence, such risk factors have yet to be identified for other types (1). This first and major issue in prevention research is not the only one.
The prevention of risk factors is crucial for cancers but also for certain chronic diseases. In France, 41% of cancers could be avoided (2), because they are linked to environments and behaviors for which effective preventive actions are possible: tobacco, alcohol consumption, unbalanced diet, sedentary lifestyle, overweight, certain infections, exposure to unprotected UV radiation, occupational and environmental exposures, etc. Much progress has been made in these areas, which deserves to be continued by capitalizing on good experiences and successful prevention programs 2 , and by designing innovative intervention mechanisms. In support of this, research must help to increase the understanding of how to act on the individual, collective, and socio-environmental determinants of health, to develop a vision capable of quantifying the expected impact of different prevention measures, prioritizing them, and acting on those which are most promising.
Screening is another issue to be considered. Serving as an essential leverage in the fight against certain cancers, it is undoubtedly a fruitful field of research: rendering one’s adhesion to screening natural, regardless of social or professional categories, or one’s relationship to health (greatly influenced by education), constitutes a real challenge, in the same way as a safer and earlier detection of potentially aggressive lesions.
Moreover, while the last decade has seen significant progress in terms of treatments, as evidenced by the development of immunotherapy and its impact on quality of life (3), support for people affected by cancer and their loved ones should also be facilitated. Improving their quality of life, alleviating the sequelae of their disease and treatment, and reintegration into social or professional life are priorities in tackling cancer. This is a third issue for prevention research, which is that of tertiary prevention (1).
To meet these three challenges, it is necessary to know which intervention models are likely to develop environments and behaviors that are favorable to health, that restore confidence in public discourse, and which are supportive for patients and their entourage (3), approaching all these actions in a perspective of equity.
This is one of the objectives of population health intervention research (PHIR): action-oriented, carried out by researchers in partnership with intervention actors, healthcare professionals, patients, caregivers, public decision-makers, and communities. The diversity of these actors shapes PHIR projects, testifies to the richness of this research, and gives it a privileged place to observe, analyze, and intervene as accurately as possible in different contexts and populations. Even if these interventions are themselves complex systems interacting with their context or larger ‘intervention systems’ (4), PHIR is making considerable progress in understanding the mechanisms thus brought into play, a key element for their transferability.
PHIR is also and above all a promising tool for devising interventions capable of tackling social and territorial inequalities in health, while at the same time not accentuating them. Too many actions are more beneficial to socially advantaged people, equipped with socio-economic resources which make them more apt to use what is put in place. In France, the risks of cancer of the lips-mouth-pharynx, larynx, and lung are more than 50% higher in the most disadvantaged men than in those belonging to the highest socio-professional categories (2). These inequalities are apparent at every step of the continuum, from risk prevention to life after illness. Far from being limited to exposures and single factors, PHIR gives an important place to social, economic, and environmental determinants (5,6). This approach is essential to the promotion of health equity and the fight against social and territorial inequalities in health, within the health sector and beyond.
The National Cancer Institute (INCa), with the support of the General Directorate of Health (DGS) and in collaboration with its partners, has been a pioneer in France in the development of PHIR. Over the past 10 years, INCa has funded more than 90 PHIR projects, including 53 through a dedicated call for projects, the budget for which now stands at more than 14 million euros. About 20 so-called ‘emerging’ 3 projects were also supported. These projects allow for the emergence of new research questions and the reinforcement of partnerships, a step taken to help ensure the quality of the projects subsequently developed. The fight against inequalities occupies a prominent place in the call for PHIR projects. More than a third of the projects address different levels of health inequalities, targeting individual factors as well as socio-economic and environmental determinants.
Since its creation in 2007, the Public Health Research Institute (IReSP) and its partners have supported research projects whose results make it possible to act on health determinants, for all diseases. Using this approach, the institute has funded 91 population health intervention research projects to date. Among them, 36 integrate the issue of social inequalities in health (including 10 definition contracts or emerging projects, and research networks) through 30 different calls for projects. This constitutes nearly €5m dedicated to the fight against health inequalities in the fields of health prevention and promotion, the fight against addictions, or even the loss of autonomy.
PHIR in France is therefore resolutely focused on the issue of social and territorial inequalities in health. After 10 years of developing this field of research, it is relevant to question in practice its contribution to the fight against inequalities. It is in this context that INCa, in collaboration with IReSP, Inserm, and the support of the DGS, organized an international meeting on January 10 and 11, 2019 in Paris. We had the immense pleasure of welcoming nearly 300 researchers, professionals, decision-makers, and citizens to initiate transversal reflection with stakeholders and discuss the contribution of population health intervention research in the fight against social inequalities and territorial health.
This meeting was in line with our commitment to promote the scientific network of PHIR in the French-speaking community. This is the fourth PHIR conference led by INCa, along with one of the first in France in 2010, on ‘Inequalities in the face of cancer: finding and intervening’; in 2014, on ‘Researchers, decision-makers and actors in the field working together’; and in 2016, on ‘Concepts, application methods and perspectives of PHIR in the field of communicable diseases and cancer’. This 2019 edition was designed by a panel of experts from various backgrounds, reflecting the multidisciplinary and multi-actor alliances specific to PHIR, chaired by Louise Potvin, one of the founding scientists of this field of research in Canada (7).
With this special issue, it is proposed to continue the reflection on ways of approaching and implementing interventions, and to outline the perspectives of intervention research as a tool to fight inequalities. This issue aims to present the current state of PHIR, since it has been promoted for 10 years as a relevant science for making progress against health inequalities. With both conceptual and practical content, the present issue is intended for the scientific community and decision-makers, stakeholders, or anyone interested in health promotion, in the hope of better rebalancing investments in our health system in favor of prevention.