Sex-specific relationships between adiposity and anthropometric measures and carotid intima-media thickness in Koreans: The Healthy Twin Study

Background/Objectives: Increased adiposity, shorter stature, shorter leg length and carotid intima-media thickening are associated with cardiovascular (CV) disease. This study aimed to evaluate the sex-specific phenotypic and genetic associations between adiposity and anthropometric measures and carotid intima-media thickness (IMT). Subjects/Methods: We measured IMT at common carotid artery (CCA-IMT), carotid bifurcation and internal carotid artery (ICA-IMT) using B-mode ultrasound, and adiposity and anthropometric measures, including body mass index (BMI), height, leg length, waist circumference (WC), waist-to-hip ratio and percentage of body fat; we also assessed conventional CV risk factors among 706 Korean adults from the Healthy Twin Study. The associations were analyzed using quantitative genetic and linear mixed analyses. Results: In linear mixed analyses, BMI and WC had independent associations with the IMT at CCA-IMT and ICA-IMT and CCA-IMT, respectively, after adjusting for age and conventional CV risk factors in men. By comparison, in women, adiposity and anthropometric measures were associated with carotid IMT only before adjusting for the covariates. In men, there were significant genetic correlations between BMI and CCA-IMT (rho(G) = 0.32 +/- 0.11), BMI and ICA-IMT (rho(G) = 0.35 +/- 0.11) and WC and ICA-IMT (rho(G) = 0.32 +/- 0.13) after adjusting for covariates, whereas in women the cross-trait genetic correlations were no longer significant after adjusting for the covariates. Conclusions: In this Korean twins and families, we found sex-specific associations between adiposity and anthropometric measures and the IMT at each segment of the carotid artery, and BMI and WC in men can be indicators predicting carotid intima-media thickening regardless of age and CV risk factors. European Journal of Clinical Nutrition (2012) 66, 39-46; doi:10.1038/ejcn.2011.150; published online 31 August 2011