Sex differences in lipid profiles in relation to the progression of glucose abnormalities

In the present study, we investigated the role of changes in blood lipids in the abolition of the lower cardiovascular risk associated with the female gender in individuals with type 2 diabetes mellitus (T2DM).

An oral glucose tolerance test (OGTT) was performed in 1091 consecutive patients (478 men and 613 women) and patients were divided into groups as follows: (i) those with normal glucose tolerance (NGT; n = 589); (ii) those with pre-diabetes (pre-T2DM), who were further divided into those with impaired fasting glucose (IFG; n = 212), impaired glucose tolerance (IGT; n = 84), and both IFG and IGT (IFG/IGT; n = 102); and (iii) those with T2DM (n = 104). Total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), apolipoprotein (apo) A-I, apoB, and the apoB:apoA-I ratio were determined in each patient. Differences in lipids between the different groups were assessed using Student's t-test.

Significantly higher triglyceride levels and an apoB:apoA-I ratio were found in NGT men (P < 0.0001), along with lower HDL-C and apoA-I (P < 0.0001). Men in the pre-T2DM group maintained a higher apoB:apoA-I ratio (P < 0.05) and lower HDL-C (P < 0.0001) compared with women. In the T2DM group, only HDL-C was lower in men compared with women (P < 0.05).

The progression of glucose intolerance from NGT to pre-T2DM and T2DM exhibits striking sex differences regarding the lipid profile. The data demonstrate a worsening of plasma lipid composition in women who become diabetic. This could explain, at least in part, the loss of the more favorable cardiovascular risk normally associated with NGT women.