Chronic-Smoking, Autoimmune disease — such as Sjögren's syndrome, inflammatory bowel disease, and primary biliary cirrhosis., Genetic abnormalities — three major groups of mutations have been identified.Drugs — thiazide diuretics, azathioprine, tetracyclines, oestrogens, valproic acid, cimetidine, and dipeptidylpeptidase-4 inhibitors (for example sitagliptin and vildagliptin), Obstructive causes — such as gallstones or pancreatic ductal strictures, Tropical causes — prevalent in specific geographical regions such as southern India