The Syndemic Theory, the COVID-19 Pandemic, and The Epidemics of Non-Communicable Diseases (NCDs).

Background: The syndemic theory is based on the interaction of two or more epidemics. This phenomenon is important in the current COVID-19 pandemic. Results: This pandemic affects all aspects of human life, including the management of non-communicable diseases (NCDs) such as cancer, diabetes, hypertension, and so on. This effect may have an impact not only on the management of the underlying NCDs but also on the infection and prognosis of COVID-19. Another aspect of this syndemic is that the health policies in each country have been revolutionized as a result of this pandemic, and the association of COVID-19 with other NCDs necessitates the implementation of new policies to properly manage this syndemic. Conclusion: In this paper, we review the syndemic theory, how the COVID-19 pandemic could be classified as a syndemic with other NCDs, and how this pandemic changes circumstances for policymakers in any country, particularly the Islamic Republic of Iran.