Effects of jejuno‐ileal bypass on serum lipoproteins and glucose tolerance in severely obese patients

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Abstract
Plasma insulin and blood glucose during oral glucose tolerance tests (OGTT) and serial determinations of serum lipoprotein fractions before and after jejuno-ileostomy in 20 severely obese (mean wt 137 kg) patients, with a mean age of 29 yr, revealed statistically significant postoperative decreases in all parameters, concomitant with a mean weight loss of 42 kg. Before the operation the patients were hyperinsulinemic and had elevated blood glucose levels during OGTT, although no patient had overt diabetes. Serum triglyceride and total cholesterol levels were normal, but HDL cholesterol was significantly lower than in controls. During follow-up at least until body weight had leveled off a mean 19 mo. postoperative, there were statistically significant reductions in blood glucose, plasma insulin, serum total cholesterol and lipoprotein fractions; there was no change in serum triglycerides. The low preoperative HDL levels decreased. Postoperative increases in arterial tissue cholesterol are coincident with the present significant decreases in HDL and in LDL cholesterol. Correlations between total cholesterol and lipoprotein cholesterol values in serum and blood glucose and plasma insulin at fast and during OGTT and changes in these parameters demonstrate interrelationships between lipid and carbohydrate metabolism. The bypass procedure most likely reduces the intestinal synthesis of HDL which in turn may increase hepatic cholesterol synthesis. Evidently there is a multifactorial etiology for the low HDL levels in the severely obese before and after jejuno-ileostomy. An increased morbidity and mortality in diabetes and complications of cardiovascular disease are discussed.