Lipoprotein oxidation and plasma vitamin E in nondiabetic normotensive obese patients

Objective: To correlate the susceptibility of low- (LDL) and very-low-density lipoprotein to oxidation in vitro and the concentrations of serum antibodies against malondialdehyde-modified LDL and plasma vitamin E with the anthropometric and laboratory characteristics of obesity. Research Methods and Procedures: A total of 75 nondiabetic, normotensive obese patients were assigned to one of four groups according to their body mass index (BMI): moderately obese (30 less than or equal to BMI less than or equal to 34.9 kg/m(2), n = 11), severely obese (35 less than or equal to BMI less than or equal to 39.9 kg/m(2), n = 20), morbidly obese (40 less than or equal to BMI less than or equal to 50 kg/m(2), n = 29), and very severely obese (BMI > 50 kg/m(2), n = 15). Results: The oxidation lag time for LDL from patients with a BMI greater than or equal to35 kg/m(2) was shorter than that for LDL from non-obese controls (n = 13), whereas very-low-density lipoprotein oxidation lag times were not significantly different. The serum antibodies against modified LDL were similar in all groups, whereas the plasma vitamin E concentrations of obese patients were decreased (p less than or equal to 0.01). There was a negative correlation between LDL oxidation lag time and BMI (r = -0.35, p = 0.0008), and between plasma vitamin E and BMI (r = -0.53, p < 0.0001) and waist-to-hip ratio (r = -0.40, p = 0.0003). Discussion: The LDL of nondiabetic, normotensive obese patients is more readily oxidized, and plasma vitamin E concentrations are low. These are both risk factors for coronary heart disease.