Obesity has been associated with increased common carotid artery (CCA) intima-media thickness (IMT), a measure of subclinical atherosclerosis. We assessed the association between genetic predisposition to obesity and CCA IMT. The study included 428 young Chinese adults with CCA IMT measured using a high-resolution B-mode tomographic ultrasound system. We created a genetic risk score (GRS) by summing the risk alleles of 6 obesity-associated genetic variants confirmed in our previous analyses. The GRS was significantly associated with greater CCA IMT (p<0.001) after adjustment for age and gender. Per 2 alleles of the GRS was related to 0.023 mm increment in IMT. The association was attenuated by one half with additional adjustment for obesity status, but remained significant (p=0.009). In addition, we found that blood pressure significantly modified the association between the GRS and CCA IMT (p for interaction=0.001). The associations between the GRS and CCA IMT were stronger in participants with systolic blood pressure (SBP) ≥120 mmHg and/or diastolic blood pressure (DBP) ≥80 mmHg (per 2 allele increment of the GRS relating to 0.028 mm greater CCA IMT, p for trend<0.001) than those with SBP<120 mmHg and DBP<80 mmHg (per 2 allele increment of the GRS relating to 0.001 smaller CCA IMT, p for trend=0.930). Our data provides suggestive evidence supporting the potential causal relation between obesity and development of subclinical atherosclerosis. Elevated blood pressure might amplify the adverse effect of obesity on cardiovascular risk.
Keywords: Blood pressure; Cardiovascular; Genetic susceptibility; Intima–media thickness.
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