By Judith Littleton, Heather Battles & Evelyn Marsters

How is it that an infection can be worse or different depending on whether someone has another disease? Why does it matter where someone lives? Why does history make disease progression different in different places? Thinking about syndemics helps us answer these questions.

Ti grew up in the Pacific Islands in the 1950s when tuberculosis (TB) was still common. When Ti was still a child, her father was sick with TB but she didn’t develop any signs of the disease herself. When she was 20, many Pacific Islanders, including Ti and her husband, migrated to New Zealand, where he worked in the freezing works (an industrial slaughterhouse where the meat was frozen before shipping) and she worked as a cleaner. They had difficulty finding rental housing. Landlords were not eager to rent to Pacific Islanders and their wages were low, which meant that the only solution to their housing problem was to share a small house with another family from the same island. In some dwellings, there were entire families occupying each bedroom. Under these stressful living conditions, Ti developed TB, possibly due to the reactivation of her long-standing latent TB infection. The disease was successfully treated at the time, although the long period of treatment was a further burden to her family. However, as later events show, Ti’s TB was probably not fully eliminated. When she was subsequently diagnosed with diabetes mellitus (DM) in her sixties, her health was poor. She developed a persistent cough and finally further tests showed that TB had once again reactivated. 

This story of one person’s journey with TB covers over 60 years of personal history. But it is not just one person’s story. It is about both Ti’s birth family and her own family. The story crosses borders, in that it affected people in both New Zealand and the Cook Islands. Nor is it a story about one disease, but rather two – one which we like to think of as on the wane (TB) and one a growing epidemic (diabetes).

Syndemics: A brief recap

As medical anthropologist Merill Singer explains, the word syndemic combines the Greek terms synergos (two or more things acting in concert to have more impact than each one singly) and demos (people). It captures how diseases, whether chronic or acute, can interact with each other under certain social and environmental conditions (e.g., poverty or air pollution) to create a point of intersection. Thinking in a syndemics framework means looking at the linkages between conditions – the common causes, the ties that bind conditions together – and then finding solutions, not just by tackling individual diseases, but by identifying and addressing the underlying connections between them.

Syndemics and diabetes

The idea of interaction sits at the centre of syndemics thinking. Often we tend to think of someone with more than one disease as having ‘co-morbidities,’ but multiple diseases may interact in ways that create additional health burdens. One disease may be stimulated to reactivate in the presence of another, as in the example of tuberculosis and diabetes above. Ti had a latent TB infection – the disease was not active and she wasn’t infectious. But then, when she developed diabetes, the resulting elevated blood sugar interfered with her body’s immune response, and so the TB infection became active (i.e., it produced symptoms like coughing, fever, and night sweats). The social and economic circumstances in which she lives (and in which many others live) caused this interaction to occur, and that interaction had many effects beyond Ti’s immediate personal experience of having both diseases – including stigma that extended to her family and community and impacts on the health of her wider family and on health care systems in both New Zealand and the Cook Islands.

Because Type II diabetes is so widespread and affects multiple bodily systems, it has been identified as a factor in many syndemics. Emily Mendenhall has described syndemic interactions between diabetes, violence, depression, and abuse in the lives of Mexican immigrant women living in Chicago[i]. But in other settings, diabetes will be understood differently, experienced differently, and be associated with different conditions. For example, in the township of Soweto (South Africa), diabetes and depression still interacted at multiple levels but the experience of distress was intertwined with HIV/AIDS[ii]. In Ontario, where there is unequal access to dental care due to the cost of treatment and the availability of services, Kaura Parbhakar[iii] found a synergistic relationship between diabetes and periodontal disease, which points to a syndemic linkage of oral health to whole body health[iv]. Clarence Gravlee has recently commented on a potential emerging syndemic of diabetes, hypertension (high blood pressure), and COVID-19, associated with systemic racism and chronic health inequities in the U.S. As we can see in Ti’s story above, syndemic interactions can also create new forms of social suffering[v] as communities are stigmatized or blamed for high rates of disease – especially for conditions like poor oral health, with visible stigmatized effects.

Time and scale

Thinking about synergistic interactions means we need to pay attention to time and scale. In Ti’s case, while the interaction between Type II diabetes and TB occurred within her individual body, the pre-conditions for the interaction occurred up to 50 years previously, at a time when tuberculosis was common in the Pacific Islands. Syndemics also force us to think more broadly – not just in medical terms, but also how experiences with one disease (such as TB) can alter people’s understandings and experiences of other conditions. These experiences are played out in individual lives and communities.

For example, in the case study from Evelyn Marsters’s doctoral study, the socio-biological syndemic relationship between diabetes and TB manifests over time and across international borders. In Rangi’s case, transnationalism and health can be seen to interact as travel for burial complicated the TB diagnosis and led to change in the TB statuses of some members of the family. Multiple generations are affected as the story moves from Rangi’s mother and weaves together the experiences of many families. This story also speaks to the vulnerability of children in the face of a diabetes and TB syndemic and conveys the reality of poverty, particularly crowded housing and insecure food supplies.

New risks for new generations

Syndemic interactions can lead to new disease risks to new generations. In the case of TB and diabetes, TB infections in adults, which can be hard to diagnose and treat, can pose a new risk to children, particularly in crowded households. This dynamic is the inverse of what we now see with Covid-19, where exposure among the young can result in interactions between the virus and other diseases of the elderly, including diabetes.

The presence of syndemic interactions can also mean that the co-occurrence of conditions opens up new sites of potential transmission. One of the consequences of advanced diabetes can be a need for renal dialysis. Dialysis units can treat many immune-suppressed people at one time, so the co-occurrence of diabetes and tuberculosis opens up to the bacteria a new site (i.e., the dialysis unit). Similarly, during the HIV/AIDS epidemic, the presence of TB patients in the same waiting rooms and hospital wards as people with HIV/AIDS contributed to a syndemic. This syndemic was caused by conditions of overcrowding, stress, and poor access to services – all aspects of poverty.

New perspectives, new solutions

Recognizing syndemics also alerts us to new ways of tackling conditions from the treatment of individuals through health systems to the broader environment. Recognizing the link between tuberculosis and diabetes, the WHO has recommended that patients with TB are screened for diabetes, while in countries with a high incidence of TB, diabetes patients should be screened for TB. Treatment regimes are really important once it is recognized that TB and diabetes are occurring together. But beyond treatment of the individual, the co-occurrence opens up other possibilities. TB treatment is often long term (six months) and involves extensive contact between the patient and health services, such as public health nurses. This engagement represents a possibility for health practitioners to pass along other messages related to diabetes prevention or smoking cessation. Co-ordinating care, particularly in high prevalence settings, makes for stronger relationships – and possibly more efficient health services. If more people are aware of the linkages between diseases and how their interaction with social and economic conditions can create new entities like syndemics, then there will be more possibilities for change.

Moving beyond individual and family care and into the realm of public health, effective coordinated health awareness campaigns should not just focus on one disease. While diabetes is often seen as a discrete condition, its potential link to an infectious disease that can spread from person to person, like tuberculosis, makes it an issue for all of us. Understanding how crowded housing, stress, and obesity are linked in different places can help spur policies that go beyond health. Seeing public health through a syndemic lens potentially offers new perspectives and new solutions.

Bringing different perspectives together

To tackle syndemics, many different professions need to work together: epidemiologists, clinicians, economists, and social scientists. This includes historians who understand how legacies of disease (e.g., historic trends in tuberculosis, or the experiences of Indigenous children in residential schools[vi]) help shape not just the diseases we face today, but also how different communities understand them.

For example, in different communities stigma can affect how many people are willing to come forward to be tested for a disease. What constitutes the stigma of a particular disease is constituted from history. For a long time, tuberculosis was thought of as a deadly disease requiring isolation of infected people in separate facilities like sanitoria. Even today, the use of mobile TB clinics was associated with feelings of stigma for a Nunavut community, while European New Zealanders report feeling shame and embarrassment when diagnosed with TB. Diabetes was traditionally tied to food and ideas of personal responsibility – it, too, is stigmatized in many communities. Indigenous people in Manitoba who had diabetes described being told “you are too fat, you eat too much,” while some treated diabetes as if it was a contagious disease.[vii] A recent survey in New Zealand showed that at least a third of people with diabetes avoided disclosing their diagnosis in order to avoid negative reactions. If we view this phenomenon through a syndemic framework, we can see the stigma associated with diabetes only adds to stress and depression, thus intensifying the interaction between conditions.

Looking backwards to move forwards

How has diabetes and its syndemic relationships to other diseases changed over time and across different places and contexts? Above, we’ve highlighted some of the syndemics in which diabetes plays a key role. Using a visual method, like diagramming (as in Figures 2 and 3), can help to make the links between the different elements of a syndemic. Figures 2 and 3 focus on the bio-social factors at the centre of syndemic linkages, but we can think beyond that to other factors that might contribute, such as stress, stigma, access to services, etc. This diagramming draws attention to the factors that hold these elements together in a particular time and place, and prompts us to ask ourselves: what could be done to sever those links and improve health?

This is the insight that syndemic thinking brings – it goes beyond attention to the biological synergies between pathogens and diseases, and beyond general acknowledgement that social conditions shape health and disease. Syndemic thinking points us to specific social and environmental conditions where we can focus our efforts for social change and government policy action. A crucial part of this is education – having a general public who understand how diseases and disease clusters are not simply ‘natural facts’ but created out of particular circumstances. Understanding can not only help lessen barriers to health, such as stigma, but also create will for changing social conditions.

The diabetes epidemic confronting the world today is a product of current conditions, but these conditions have come out of different histories. Understanding diabetes today and preventing it in the future involves us all looking backwards and using that understanding of interactions, including interactions with different diseases and social conditions to craft a different future.


[i] Mendenhall, Emily (2012) Syndemic suffering: social distress, depression, and diabetes among Mexican immigrant women. Left Coast Press, Walnut Creek, CA.

[ii] Mendenhall, Emily (2012) Syndemic suffering: social distress, depression, and diabetes among Mexican immigrant women. Left Coast Press, Walnut Creek, CA.

[iii] Kaura Parbhakar, K. (2019). Self-reported oral health status and diabetes outcomes in a cohort of diabetics in Ontario, Canada (13427360). Available from ProQuest Dissertations & Theses Global. (2303837691).

[iv] Gravlee, C. C. (2020) Systemic racism, chronic health inequities, and COVID-19: A syndemic in the making? American Journal of Human Biology e23482

[v] Rylko-Bauer, B., & Farmer, P. (2016). Structural violence, poverty, and social suffering. In D. Brady & L. Burton (Eds). The Oxford handbook of the social science of poverty. Oxford: OUP pp. 47-74.

[vi] Jacklin, K. M., Henderson, R. I., Green, M. E., Walker, L. M., Calam, B., & Crowshoe, L. J. (2017). Health care experiences of Indigenous people living with type 2 diabetes in Canada. Cmaj189(3), E106-E112.

[vii] Iwasaki, Y., Bartlett, J., & O’neil, J. (2004). An examination of stress among Aboriginal women and men with diabetes in Manitoba, Canada. Ethnicity & Health9(2), 189-212.

This article was originally featured on Defining Moments Canada and has been republished with permission. 

Judith Littleton is a Professor in Anthropology at the University of Auckland. She is an expert in medical anthropology. 

Heather Battles is a Lecturer in Anthropology at the University of Auckland. She is an expert in infectious diseases. 

Evelyn Marsters has a Ph.D. from the University of Auckland. Her research explores health inequalities and gender issues. 

Disclaimer: The ideas expressed in this article reflect the author(s) views and not necessarily the views of The Big Q. 

You might also like:

How are illness and disease created in particular bodies? ▶

Are antibiotics to blame for some modern diseases? 🔊