Commentary: Co-occurrence of tuberculosis and diabetes: new paradigm of epidemiological transition.

In his classic 1971 paper, Abdel Omran put forward the theory of The Epidemiologic Transition, positing that societies experience three principal stages of disease status: beginning with an Age of Pestilence and Famine, followed by an Age of Receding Pandemics and finally an Age of Degenerative Disease. Although exceptions to Omran’s theory exist, the concept remains relevant to contextualize major shifts in epidemic dynamics. The recently observed co-occurrence of tuberculosis (TB) and diabetes mellitus (DM) pandemics, however, represents a new phenomenon in the classic epidemiological transition, a consequence of rapidly growing non-communicable diseases (i.e. DM)—a result of transitioning lifestyles towards greater intake of calories and lower physical activity—coupled with an inability to reduce the global burden of TB. The shifting epidemiology, sociology and clinical care of the concurrent DM–TB disease state, like the combination of other infectious and chronic diseases, will influence public health agendas and challenge the classical silos of communicable vs non-communicable diseases. This situation, however, may also offer major opportunities for research and for rethinking health systems’ orientation and structure. Omran accurately predicted that societal improvements in economic, social, cultural and political capacities would affect epidemic transitions, but he did not foresee that elements of globalization and economic development could so quickly bring about an Age of Degenerative Diseases before the Age of Receding Pandemics was curtailed. The increasing co-occurrence of TB and DM is a clear case in point, especially in countries with rapidly emerging economies such as India and China, resulting in a confluence of two pandemics—one communicable and another non-communicable. In this issue of the IJE, Goldhaber-Fiebert et al. report an association between DM and TB from a population-based survey of lowand middle-income countries (LMIC) that is consistent with findings from previous research. DM has been recognized as a risk factor for TB for decades, but although the link between DM and TB is not new, only with the recent explosive DM pandemic has the importance of understanding the relationships between DM and TB emerged as a global health priority. TB causes enormous morbidity and mortality globally; annually, 49 million people develop active TB and nearly 2 million die due to TB—now the second leading cause of death from an infectious disease. The overwhelming number of TB cases and deaths occur in LMIC. At the same time, more than 285 million adults globally have DM and this number is projected to increase to 440 million by 2030, with three-fourths of affected people living in LMICs, where the disease strikes at younger ages and even lower body mass indices (BMIs). The evolving epidemiology of concomitant DM and TB is of particular importance in middle-income countries with emerging economies, which still have large TB burdens coupled with dramatic increases in DM due to rapid changes in lifestyles. DM may contribute to a significant proportion of the TB cases in many such countries. Goldhaber-Fiebert et al. demonstrate the strength of the association (adjusted prevalence odds ratio of 1.81) between DM and TB in a large population-based survey, and use ecological data to highlight the impact of an expanding DM epidemic Published by Oxford University Press on behalf of the International Epidemiological Association