Oxidized lipids in insulin-dependent diabetes mellitus: a sex-diabetes interaction?

The increased cardiovascular risk experienced by patients (particularly women) with insulin-dependent diabetes mellitus (IDDM) is not fully explained by conventional risk factors including lipid and lipoprotein concentrations. To determine if plasma lipid peroxide concentrations are relevant to these observations, levels of thiobarbituric acid reactive substances (TBARS) were measured in 56 young adult subjects with IDDM (mean age, 33 years; duration, 24 years) and 56 age- and sex-matched healthy controls. The TBARS concentration was significantly higher in women with diabetes than in female controls (7.4 v 4.5 nmol/mL, P = .001), but not in men with IDDM (5.1 v 5.3 nmol/mL). Diabetic men showed a significant correlation between triglyceride and TBARS concentrations (P < .01), a finding not seen in diabetic women. Furthermore, there was a correlation between glycemic control (hemoglobin A1 [HBA1]) and TBARS in diabetic men, but not in women (P < .01). These findings raise the possibility that the relatively greater increase in cardiovascular disease risk seen in IDDM women compared with men may relate to their increased degree of lipid peroxidation, which is independent of their degree of glycemic control.