Lipid characteristics and malondialdehyde level in the sera of obese people.

In the blood sera of 70 obese persons (26 men, 44 women) some lipid components and malondialdehyde (MDA) level were determined before slimming. The people were classified into groups of hyperlipoproteinaemia on the basis of laboratory results, according to Fredrickson and Lees. In 32 people with high blood cholesterol level (above 5.7 mmol) there were negative correlations between MDA and high-density lipoprotein (HDL) fractions. Correlation coefficients were the greatest in the group IIa of hyperlipoproteinaemia (HDL-C. r = -0.74; HDL-2-C. r = -0.54; HDL-3-C. r = -0.78). Correlations were not found in subjects with a normal cholesterol level. The results were attributed to the formation of oxidized cholesterol products, caused by lipid peroxidation, which may decrease the HDL synthesis. It seems that in hypercholesterolaemia coupled with obesity, lipid peroxidation can contribute to the reduction in HDL levels, which is an important protective factor against cardiovascular diseases.