Apolipoprotein B/apolipoprotein A-I in relation to the metabolic syndrome and change in carotid artery intima-media thickness during 3 years in middle-aged men.

Objective: The apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio is a measure of the relationship between different lipoprotein particles and a powerful predictor of coronary death. The aim was to examine whether apoB/apoA-I was associated with the metabolic syndrome (MetS) at baseline and also with the future change in carotid artery intima-media thickness (IMT).

Methods: In 313 58-year-old men, carotid artery IMT was measured bilaterally by high-resolution B-mode ultrasound at baseline and after 3 years of follow-up. Serum apolipoprotein concentrations and the components of MetS were measured at study entry.

Results: ApoB/apoA-I showed statistically significant associations with body mass index, waist-to-hip ratio, high-density lipoprotein (HDL) cholesterol, triglycerides, low-density lipoprotein (LDL) particle size, insulin, and diastolic blood pressure. Two thirds of the patients with MetS had high apoB/apoA-I ratios (>0.90) compared with one third of those without the syndrome (P<0.001). The IMT change was associated with apoB, total cholesterol, LDL cholesterol, triglycerides, and inversely with HDL cholesterol and LDL particle size at entry, and there was a strong colinearity between these variables. The subjects with apoB/apoA-I above the first tertile (0.74) had a 20-microm-higher (95% CI, 7 to 33) annual increase in IMT compared with those below this level after adjustment for blood pressure and smoking.

Conclusions: The apoB/apoA-I ratio was strongly associated with MetS and its components at baseline. ApoB/apoA-I at baseline was related to the change in carotid artery IMT during 3 years of follow-up. There was a strong colinearity between apoB/apoA and the atherogenic lipids.