Serum Lipoproteins in Massive Obesity

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Abstract
Serum lipoproteins in 31 grossly obese males and females were determined by preparative ultracentrifugation before and after jejunoileal shunt operation. The results were compared with data from a randomly selected group of healthy controls. Before surgery a type IV hyperlipoproteinaemia was found in 5/11 men, which reverted to normal after operation. The obese females had a lower VLDL TG concentration which did not fall after surgery. In 10/11 males and 19/20 females the HDL cholesterol concentration was below the median value for controls before surgery. The patients were followed up to 55 months after surgery and the lipoprotein pattern was repeatedly determined. The mean weight loss was about 30% at the time of the last lipoprotein analysis. The major finding was a marked reduction of LDL cholesterol, about 40%. The LDL TG concentration was not affected. The LDL composition thus changed: at all TG concentrations the LDL of the operated patients contained less cholesterol than LDL of controls. On agarose electrophoresis a β‐lipoprotein with increased mobility, referred to here as a “rapid β” lipoprotein, could be demonstrated in about 65% of the obese subjects before operation. After surgery this “rapid β” was seen in about 80% of the cases. No explanation for this lipoprotein abnormality can be offered as yet. A negative correlation between HDL cholesterol and VLDL TG has been described in several earlier studies. The values for our obese subjects were found below such a regression line of controls both before and after operation. A low HDL cholesterol concentration seems to constitute a risk factor for the development of atherosclerotic manifestations. Our data are in agreement with a hypothesis that the increased risks for atherosclerosis, seen in obese subjects, could be attributed in part to the low HDL cholesterol values seen in these subjects.