Syndemics: health in context

The Lancet
Mar 04, 2017 Volume 389 Number 10072 p881-982 e3

Syndemics: health in context
The Lancet
Syndemics, as a new Series published in today’s Lancet details, is a conceptual framework for understanding diseases or health conditions that arise in populations and that are exacerbated by the social, economic, environmental, and political milieu in which a population is immersed. A syndemic, or synergistic epidemic, is more than a convenient portmanteau or a synonym for comorbidity. The hallmark of a syndemic is the presence of two or more disease states that adversely interact with each other, negatively affecting the mutual course of each disease trajectory, enhancing vulnerability, and which are made more deleterious by experienced inequities.

Perhaps the most unique feature of the syndemic approach to understanding various disease states and the way in which they cluster is the emphasis on the situation and circumstances in which individuals live. In other words, syndemics fundamentally rely on context. When introduced in the 1990s by medical anthropologist Merrill Singer, the notion of a syndemic was used to describe the interactions among substance abuse, violence, and AIDS (SAVA), that had become a full-blown health crisis in Hartford, CT, USA. While investigating HIV prevention in drug users, researchers took notice of the constellation of elements that impinged on risk, structural factors such as lack of housing and poverty, and social aspects such as stigma and lack of support systems—all reinforcing the disease burden.

The observation that these factors did not merely exist in parallel, but were intertwined and cumulative, offered a branch point for clinical medicine and public health interventions. These fields have made appreciable strides in recognising that interventions for combating and treating disease must take a more multifactorial tack, nevertheless there exists a great need and opportunity to more widely apply the principles of the syndemic approach. In the years since SAVA was identified, there have been other syndemics described that include HIV/AIDS as a component, such as the HIV–malnutrition–food insecurity syndemic in sub-Saharan Africa. Alternatively, other existing and emerging syndemics centre on non-communicable diseases (NCDs) such as VIDDA (violence, immigration, depression, type 2 diabetes, and abuse) in women who have emigrated to the USA from Mexico.

Whether communicable diseases or NCDs, or set in high-income countries or low-income and middle-income countries (LMICs), there are similar forces at work that can perpetuate or accelerate existing syndemics. Specifically, rapid changes can precipitate conditions conducive to developing syndemics. For example, globalisation patterns have quickly and fundamentally changed dietary patterns in LMICs by increasing access to high-calorie foods and processed carbohydrates, radically increasing the proportion of individuals with type 2 diabetes. Changes in political and economic conditions, and relatedly the breakdown of protective health measures or infrastructure, can induce differentially and additive detrimental effects on specific populations.

The political and public health changes underway in the USA are especially worrisome in their potential for spurring a new wave of unforeseen health crises. The VIDDA syndemic may serve as a harbinger of sorts for other potential immigrant health-related syndemics because of the current uncertainty around immigration policy. After the executive order issued on Jan 25, 2017, immigration enforcement has pushed many people who were previously at low risk for deportation into an uneasy and unwelcome spotlight. Several major news outlets have reported recently that health-care centres have already noted a downturn in the number of immigrant patients keeping appointments for chronic conditions such as diabetes and hypertension. It is well documented that Hispanic patients are less likely to seek medical attention than are other ethnic groups, but in the wake of an already precarious climate for Mexican immigrants, the emerging accounts highlight an even greater vulnerability because of new political threats. From a clinical perspective, applying a syndemic approach is novel and valuable for expanding the focus from why a patient has a poor outcome (eg, dysregulated blood sugar) to what other factors are contributing.

Although there may be little that clinical practitioners and public health interventionists can do about the presence of social and political circumstances that might negatively affect health, the syndemic framework allows for the potential to mitigate those effects by appreciating the complex nature of certain diseases and conditions and for addressing the array of factors that give rise to them. In the pursuit of practising more socially conscious medicine, syndemics suggest that context is key.