Phenotypic and genetic relationships between kidney function and carotid intima-media thickness in Koreans: the Healthy Twin Study

Abstract

Background: The phenotypic and genetic relationships between carotid intima-media thickness (CIMT) and estimated glomerular filtration rate (eGFR) or urinary albumin-creatinine ratio (ACR) were evaluated in Korean twins and families.

Methods: We recruited 688 participants (296 individual twins and 392 singletons, age 30-74 years) who were without myocardial infarction and stroke among participants in the Healthy Twin Study. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. CIMT was measured using B-mode carotid ultrasound. Covariates were sex, Framingham risk scores, alcohol use, exercise, BMI, high-sensitivity C-reactive protein and triglycerides. Quantitative genetic and linear mixed analyses were performed.

Results: In adjusted models there were associations between kidney function and CIMT with [beta] estimates ranging from -0.022 to -0.032 between eGFR and CIMT, and from 0.042-0.060 between ACR and CIMT. The covariate-adjusted heritabilities for eGFR, ACR and composite CIMT were 0.75, 0.32 and 0.45, respectively (p < 0.001). The adjusted genetic correlation between eGFR and CIMT was from -0.20 to -0.28 (p < 0.05), whereas there was no genetic correlation between ACR and CIMT.

Conclusion: Kidney function is a surrogate marker of carotid atherosclerosis and further studies of the pleiotropic relationships between CIMT and eGFR are warranted.