Increased Plasma 7β-Hydroxycholesterol Concentrations in a Population With a High Risk for Cardiovascular Disease

Abstract

Abstract —The mortality in coronary heart disease among 50- to 54-year-old men is 4 times higher in Lithuania than in Sweden. It was recently suggested that traditional risk factors could not explain this mortality difference. LDL of Lithuanian men showed, however, a lower resistance to oxidation than that of Swedish men. In addition, the plasma concentration of γ-tocopherol, lycopene, and β-carotene were lower in Lithuanian men. In the present investigation, we determined plasma oxysterols in men from Lithuania and Sweden and found that the plasma concentration of 7β-hydroxycholesterol was higher in Lithuanian men, 12±5 versus 9±8 (SD) ng/mL ( P =0.0011). This oxysterol is a cholesterol autoxidation product and there is no indication that it should have an enzymatic origin. Mean LDL oxidation lag time was shorter in Lithuanian men (75±14 versus 90±13 minutes, P <0.0001) and the concentration of LDL linoleic acid was lower (249±56 versus 292±54 μg/mg of LDL protein, P <0.0001). Lipid corrected γ-tocopherol was 0.07±0.02 mg/mL in Vilnius men and 0.12±0.04 mg/mL ( P <0.0001) in Linköping men. There was a negative correlation between the concentration of 7β-hydroxycholesterol and lag time ( R =−0.31, P =0.0023). It is suggested that the higher 7β-hydroxycholesterol concentration in Lithuanian men is an indication of an increased in vivo lipid peroxidation.