A U-shaped relationship between ankle-brachial index and carotid intima-media thickness in a Chinese population of Inner Mongolia.

AIM: The study was designed to investigate the relationship between ankle-brachial index (ABI) and carotid intima-media thickness (IMT), and provide scientific basis for primary and secondary prevention of atherosclerotic diseases.

METHODS: Participants were recruited for this investigation from Inner Mongolia in China through cluster multistage and random sampling. ABI and carotid-IMT were measured for each subject. Periphery arterial disease (PAD) was defined as an ABI≤0.9 in either leg. ABI values were divided into eight groups at every 0.05, and three carotid-IMT measures were compared among groups separately using analysis of variance (ANOVA) and multivariate linear regression analyses.

RESULTS: The results indicated that the prevalence of PAD among 1236 participants was 1.9%. The average common carotid IMT was 0.70±0.21 mm, internal carotid IMT 0.77±0.24 mm, and carotid artery bifurcation IMT 0.78±0.25 mm. A U-shaped relationship was observed that the values of common carotid, carotid artery bifurcation, and internal carotid arteries IMT were decreased at first then increased as ABI values increased. The U-shaped relationship between ABI and three carotid-IMT measures were remained after adjusting for covariates.

CONCLUSION: The data suggests that carotid IMT values are correlated with ABI values in a U-shaped curve. Increased carotid IMT is correlated with the high prevalence of PAD in population of Inner Mongolia in China.