Table 3.

Associations between average eICA tortuosity index (AICATI) and subjects’ characteristics.

Characteristics	Spearman’s rank correlation coefficient		Multiple linear regression
	ρa	p-Value	βb	p-Value	VIF
Age (years)	0.105	0.262	0.052	0.559	1.092
Male sex	−0.267	0.004	−0.222	0.008	1.004
BMI (kg/m2)	0.386	<0.001	0.065c	<0.001	1.004
Hypertension	0.151	0.106	0.036	0.681	1.095
DM	0.076	0.416	0.046	0.591	1.051
Dyslipidemia	0.115	0.218	0.046	0.594	1.029
CAD	−0.109	0.245	−0.041	0.634	1.016
Smoking	0.033	0.723	0.186	0.059	1.379

^aSpearman’s rank correlation coefficient between AICATI and each variable; ρ: Spearman’s correlation coefficient.

^bMultiple linear regression analysis, β: parameter estimate; eICA tortuosity index was converted into natural logarithmic equivalent value for statistical analysis; exponentiated coefficient exp(β) for BMI was 1.067, exp(β) for male was 0.801.

^cData are presented as natural logarithmic eICA tortuosity index per unit increase in BMI (kg/m²).

DM, diabetes mellitus; CAD, coronary artery disease; eICA, extracranial internal carotid artery; VIF, variance inflation factor; BMI, body mass index.