Non-alcoholic steatohepatitis: Association with obesity and insulin resistance, and influence of weight loss

Non-alcoholic steatohepatitis (NASH) is a disease of emerging identity and importance, and is now considered as one of the commonest liver diseases in western countries. It is frequently associated with severe obesity, especi ally abdominal adiposity, and is intimately related to various clinical and biological markers of the insulin resistance syndrome. Especially, both th e prevalence and the severity of liver steatosis are related to male sex, b ody mass index, waist circumference, hyperinsulinaemia, hypertriglyceridaem ia and impaired glucose tolerance or type 2 diabetes. A substantial weight loss following gastroplasty is accompanied by a marked reduction in the pre valence and the severity of the various biological abnormalities of the met abolic syndrome and, concomitantly, by an important regression of liver ste atosis in most obese patients. However, in some patients, this rapid and dr astic weight loss may result in a mild increase in inflammatory lesions (he patitis), despite the regression of steatosis, which might result from the rapid mobilization of fatty acids or cytokines from adipose tissue, especia lly visceral fat. The intimate relationship between NASH and obesity leads to the concept that NASH may be considered as another disease of affluence, as is the insulin resistance syndrome and perhaps being part of it.