This learning note written based on discussions held over a journal club where I disucssed Nancy Krieger’s influential article advancing the [**eco-social theory**](https://academic.oup.com/ije/article-abstract/30/4/668/705885) in social epidemiology. Her work synthesizes and critiques decades of research across disciplines to offer a more integrated understanding of health inequalities. ## **Science as a Social Product** A key theme in Krieger’s work is that science itself is a **social product**, shaped by who conducts it, what questions are asked, and what methods are considered valid. She opens her paper with a quote that captures this idea: > “Once we recognize the state of the art is a social product, we are freer to look critically at the agenda of our science, its conceptual framework and accepted methodologies and to make conscious research choices.” This resonates with my own oft-used distinction between [[On merit in science|science and the scientist]]. While science aspires for objective truths, scientists are shaped by their **socio-political and cultural environments**, which influence research agendas and interpretations. This reflexive awareness is crucial for equity-focused health research. ## **What is Social Epidemiology?** [**Social epidemiology**](https://en.wikipedia.org/wiki/Social_epidemiology) seeks to understand how **social structures, norms, and power relations** shape health outcomes across populations. From its early days, the field grappled with explanations of differences in health patterns, often reinforcing prejudiced views, such as attributing worse health outcomes in black populations (in the US) to genetics or behaviour. Krieger critiques this reductionism and demonstrates how such framing could reinforce existing social biases. ## **Three Theoretical Traditions in Social Epidemiology** Krieger outlines **three dominant theoretical approaches** to explain social inequalities in health: ### **Psychosocial Theory** This theory examines how social stressors (like poverty, discrimination, and exclusion) influence individual mental and physical health through neuroendocrine pathways. While important, psychosocial theory is critiqued for focusing too narrowly on **individual-level mechanisms** and not adequately addressing **structural drivers**. Krieger invokes [**Aaron Antonovsky’s**](https://en.wikipedia.org/wiki/Aaron_Antonovsky) famous analogy: > _“Why are some people tossed into the river in the first place, and who is doing the tossing?”_ ### **Social Production of Disease / Political Economy of Health** This tradition shifts focus to structural factors, such as capitalism, racism, and colonialism, that shape the distribution of resources, exposures, and risks. Influenced by thinkers like [**Vincente Navarro**](https://monthlyreview.org/articles/inequalities-are-unhealthy/), it interrogates the **upstream causes** of poor health, including policy decisions, governance priorities, and material inequality. Example: Blaming slum dwellers for stagnant water-related diseases ignores the structural reasons why some areas are neglected in sanitation and public services. ### **Eco-Social Theory(Krieger’s own)** Krieger proposes a more integrative approach, drawing from ecology, political economy, and biology. Key constructs include: - [**Embodiment**](https://jech.bmj.com/content/59/5/350/): How people biologically incorporate the material and social world they live in. - **Pathways to Embodiment**: How social hierarchies like caste, gender, race translate into physiological outcomes. - **Cumulative interplay of exposure, susceptibility, and resistance**: How repeated disadvantage leads to persistent health outcomes. - **Accountability and Agency**: A reminder to focus on **power** and **responsibility** in shaping health outcomes. This theory avoids either/or binaries (biological vs social) and offers multi-level explanations of disease patterns. ## **Methodological Reflections** Some colleagues raised critical questions about how such complex, theory-rich approaches can be studied empirically. Krieger’s own preference for quantitative modeling was debated, especially when contrasted with [social science approaches in HPSR](https://equityhealthj.biomedcentral.com/articles/10.1186/s12939-018-0862-5). Others noted the complementarity of Krieger’s eco-social approach with [intersectionality](https://www.tandfonline.com/doi/full/10.1080/01419870.2017.1312008), though they stem from different intellectual traditions. Intersectionality helps understand how multiple axes of identity shape lived experience, while eco-social theory anchors those experiences in broader structural and ecological processes. ## **On Theory and Research Practice** Krieger’s article reinforces that theory matters. Without theoretical grounding, even methodologically sound research can reinforce harmful assumptions. Theory helps: - Frame better research questions - Identify meaningful variables - Interpret results within the right social context Researchers must apply theory at multiple levels, starting from tool design to personal reflexivity. ## **Suggested Readings** - Nancy Krieger. _Epidemiology and the People’s Health_ (book) - Gita Sen et al. (2007). [Unequal, unfair, ineffective and inefficient. Gender inequity in health: why it exists and how we can change it](https://archive.ids.ac.uk/mab/files/unequal-unfair-ineffective-and-inefficient-gender-inequity-health-why-it-exists-and-how-we-can.html) - [[Social Epi theories Krieger|discussion on Theories for social epidemiology in the 21st century: an ecosocial perspective]]