The Correlation Between the Cardio-ankle Vascular Index (CAVI) and Serum Amyloid A in Asymptomatic Japanese Subjects

Chronic inflammation has received a great deal of attention due to the role it plays in cardiovascular disease (CVD). The cardio-ankle vascular index (CAVI) has recently been developed to evaluate arterial stiffness. This index is independent of blood pressure at the time that it is measured, making it a better measure for clinical studies on the prevention of CVD. Information on the association of serum amyloid A (SAA) with arterial stiffness in relatively healthy subjects is still scarce. The aim of the present study was to investigate the potential correlation between SAA and CAVI in asymptomatic Japanese subjects. In addition to SAA and CAVI, data on smoking status, body mass index, blood pressure, and serum/plasma biochemical indices such as glucose and total cholesterol were collected in 387 nonmedicated and CVD-free adult subjects during a health check examination (male/female 191/196, mean age 61.8 years). Among them, a randomly selected subgroup of 256 subjects (male/female 133/123, mean age 62.4 years) had a full dataset, including low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, and hemoglobin A1c. Among the whole population, CAVI levels were significantly higher in males than in females [mean 8.5 ± (SD 1.1) vs. 8.2 ± 1.1, p < 0.05], while SAA levels were slightly but nonsignificantly higher in females than in males [median 6.4 (interquartile range 4.0-9.3) μg/mL vs. 5.1 (3.5-8.4)]. In a multiple linear regression analysis, CAVI was weakly but significantly, independently, and positively correlated with SAA (β-coefficient 0.200, p < 0.01). The results of the same analyses for the randomly selected subgroup were relatively similar to the findings for the whole population. SAA may be a positive inflammatory factor associated with arterial stiffness, and the clinical relevance and the biological mechanism for this relationship should be established in future studies.