Ichiro Kawachi, PhD

John L. Loeb and Frances Lehman Loeb Professor of Social Epidemiology, Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health

Ichiro Kawachi, MB.ChB., Ph.D., is the John L. Loeb and Frances Lehman Loeb Professor of Social Epidemiology at the Harvard T.H. Chan School of Public Health. Kawachi received both his medical degree and Ph.D. (epidemiology) from the University of Otago, New Zealand. He has taught at Harvard since 1992.

Kawachi is the co-editor (with Lisa Berkman) of the first textbook on Social Epidemiology, published by Oxford University Press in 2000 (2nd edition published in 2014, with Lisa Berkman & Maria Glymour). His other books include Social Capital and Health with S.V. Subramanian & Daniel Kim (Springer, 2008); the Oxford Handbook of Public Health Practice (Oxford University Press, 4th edition forthcoming in 2018); Global Perspectives on Social Capital and Health (Springer 2013) with Soshi Takao & S.V. Subramanian; and Behavioral Economics and Public Health with Christina Roberto (Oxford University Press, 2016). In 2018, the completely revamped 2nd edition of Neighborhoods & Health will be published by Oxford (edited by Dustin Duncan & Ichiro Kawachi).

In 2013, he launched a massive, open online course (MOOC) through HarvardX called “Health and Society” (PHx 201), in which 32,000 participants registered from throughout the world. Kawachi is the Co-Editor in Chief (with S.V. Subramanian) of the international journal Social Science & Medicine, as well as the sister open access journal, SSM – Population Health. He is an elected member of the Institute of Medicine of the US National Academy of Sciences, and ISI Highly Cited Researcher (General Social Sciences).


Social Determinants of Health
I am broadly interested in the social determinants of population health and health disparities. To use Isaiah Berlin’s typology, I classify myself as a fox not a hedgehog. My investigations span the range from macro-social determinants of population health (e.g. income inequality, social cohesion), to meso-level influences (neighborhood and workplace contexts), down to the individual-level (stress, and psychosocial risk factors for cardiovascular disease).

Social capital and social cohesion

I have made seminal contributions to the link between health and “social capital”, defined as the resources accessed through social networks. I am particularly interested in the health effects of social cohesion in residential communities, workplaces and schools. Known as the Roseto effect (from Stewart Wolf’s classic study in a Pennsylvania community of that name), social cohesion is hypothesized to promote health through reciprocity exchanges, the maintenance of norms among community members, as well as the lubrication of collective action through trust. My current NIH-funded project is based in Iwanuma city, Japan, where our team is examining the longitudinal impacts of community social cohesion on resilience and recovery in the aftermath of the March 11, 2011 Great Eastern Japan earthquake and tsunami.

Disaster resilience and aging-relevant health outcomes

I am the PI of the Iwanuma Study (R01AG042463-04), which was established with the objective to investigate the role of social cohesion in promoting disaster resilience among older survivors of the March 11, 2011, earthquake & tsunami in Japan. Leveraging a unique quasi-experimental design — using data on survivors that pre-dates the disaster — we have sought to documented the risk and protective factors for disaster-related health outcomes (PTSD, cognitive decline, functional disability) in an aging population.

Collateral health effects of social ties

I’m also interested in the collateral health effects of social ties – for example, the impacts of social integration on suicide risk, as well as the protective influence of religious service attendance. Other investigations have explored the role of family bereavement on the health of survivors (explored through Swedish registry data), birth order effects on health among siblings, the effects of marital transitions on health behaviors (in large panel datasets), and the spillover effects of care-giving on the health of care-givers.

Neighborhood influences on health

With colleagues in Finland and Japan, I have been interested in examining neighborhood contextual influences on health outcomes, including the impacts of local food environment and built environment characteristics on physical activity, obesity, and other health-related behaviors (alcohol & tobacco consumption). We are particularly interested in designs that improve on causal inference to overcome endogenous neighborhood effects – e.g. fixed effects approaches in which changes in neighborhood environment (natural experiments) are examined in relation to changes in the behaviors/health of residents.

Income inequality and population health

I have conducted empirical research on the potentially damaging health consequences of growing inequality, earlier summarized in my books, The Health of Nations (New York: The New Press, 2002, with Bruce Kennedy), and Income Inequality and Health: A Reader (New York: The New Press, 1999, with Bruce Kennedy and Richard Wilkinson). With collaborators I have been looking at the impacts of income inequality on health in the United States, Brazil, and Japan. Our research has focused specifically on two hypothesized links between income inequality and health: (a) the deleterious consequences of relative deprivation and upward social comparisons, and (b) the “pollution” effects of income inequality on society, assessed through multi-level analysis.

Psychosocial work environment

Research projects with international collaborators have investigated the impacts of psychosocial work environment on the health of workers – e.g. the adverse consequences of job strain, job insecurity and the rise in non-standard work (precarious employment), and the transition to retirement. I am particularly interested in the health of workers in the context of two global trends: (a) the aging of the workforce, and (b) the demand for “flexible labor” in the era of globalization.

Behavioral economics in public health

As the Chair of a behavioral sciences department, I strongly believe that public health must engage with discoveries in the field of behavioral economics. Towards that end, I teach a course on “Understanding Health Behavior: Insights from Behavioral Economics” (SBS 278), and co-edited a textbook (with Christina Roberto) on applications of behavioral economics to public health.


MB.ChB., 1985, Otago University, New Zealand
Ph.D., 1991, Otago University, New Zealand