Tropical diabetes or type 5: emerging range of diabetes in tropics

Distinct forms of diabetes have been noted in its more atypical presentations and forms. Tropical Diabetes is one of them, and it was classified as such long ago based on patients’ clinical data in their history of travel to subtropical areas. In simpler terms, the type of diabetes which derives from tropic and subtropic regions is described as Tropical Diabetes. This subtype was initially postulated to be prevalent in underdeveloped nations suffering from chronic shortage of food and malnutrition. It consists of an array of varieties which include Fibrocalculous Pancreatic Diabetes (FCPD) and Malnutrition-Related Diabetes Mellitus MRDM. Alongside this initial definition, modern findings on tropical diabetes surfaced. A wider range of consequences including genetic factors and dietary toxins like cyanogenic glycosides from cassava and other regions into the picture. In addition, the epidemiological transition pertaining to newly developed and moderately developed tropical countries has further changed the scope of this classification. Such countries are undergoing progression within urban centers, encountering shifts with their diets, and the burden concerning metabolic diseases. Along these factors, all these transcend the known limits of tropical diabetes. This review explains the development of tropical diabetes from a historical, pathophysiological, clinical, and epidemiological perspective, with a focus on the crossroad of exocrine pancreatic insufficiency, insulin deficiency, and some degree of insulin resistance in the studied population, new data on SPINK1 mutations and other genetic markers of the disease are also provided. Distinction of diabetes from other types is supported by its unique features like not having ketosis with the variable insulin therapy response set it apart from classical type 1 and 2 diabetes. Moreover, the review evaluates the tropical diabetes and micronutrient deficiency relationship, in particular with vitamin A suspected to play a role in pancreatic β-cell dysfunction. Examining the context of tropical diabetes also implies diagnostic and therapeutic challenges as well as reclassification possibilities. Conclusions reflect the importance of diagnostics tailored to the heterogeneity of the diabetic phenotypes in these regions. Thus, the goal of the review is situated within what tropical diabetes is and how it can be clinically identified and managed in endemic areas integrating historical paradigms with modern progress.