What is definition of double burden disease?

Double burden disease is a term used in epidemiology and public health to refer to the phenomenon where a population simultaneously experiences high levels of both chronic diseases (such as heart disease, cancer, and diabetes) and infectious diseases (such as malaria, tuberculosis, and HIV). This situation is often seen in low- and middle-income countries where there is a lack of adequate healthcare infrastructure, resources, and funding to effectively address both types of diseases.