Stress-induced cardiac autonomic reactivity and preclinical atherosclerosis: does arterial elasticity modify the association?

Figures & data

Table 1. Characteristics of the study participants.

Variables	Mean	SD
Age in 2001 (24–39), years	30.67	5.03
Cdist, %/10 mmHg	2.25	0.58
IMT, mm	0.59	0.09
HR baseline, bpm	71.13	8.97
RSA baseline, log ms^2	2.83	0.25
PEP baseline, ms	96.28	11.81
HR reactivity score, bpm	15.91	10.55
RSA reactivity score, log ms^2	−0.10	0.25
PEP reactivity score, ms	−14.63	10.62
LDL cholesterol, mmol/l	3.21	0.73
HDL cholesterol, mmol/l	1.28	0.30
Triglycerides, mmol/l	1.26	0.56
Insulin, mU/l	7.74	4.71
Systolic BP, mmHg	114.12	14.03
Diastolic BP, mmHg	70.06	10.24
BMI, kg/m^2	25.06	4.43

Cdist, carotid artery distensibility; IMT, intima-media thickness; HR, heart rate; RSA, respiratory sinus arrhythmia; PEP, pre-ejection period; HDL, high-density lipoprotein; LDL, low-density lipoprotein; BP, blood pressure; BMI, body mass index; SD, standard deviation.

Table 2. Bivariate correlations between the cardiovascular risk factors variables.

	1.	2.	3.	4.	5.	6.	7.	8.	9.	10.	11.
1. Gender^a	1
2. Age	0.09	1
3. BMI	0.09	0.02	1
4. LDL cholesterol	−0.01	0.36**	0.06	1
5. HDL cholesterol	−0.39**	−0.00	−0.08	−0.08	1
6. Triglycerides	0.13	−0.10	−0.08	0.21	−0.20	1
7. Insulin	0.22	0.14	−0.16	−0.23	−0.06	−0.12	1
8. Systolic BP	0.19	0.25	−0.17	0.02	−0.16	0.10	0.17	1
9. Diastolic BP	0.09	0.08	−0.14	−0.02	−0.08	0.13	0.23	0.77***	1
10. Cdist	−0.24	−0.29*	−0.03	−0.24	0.09	−0.11	−0.11	−0.10	−0.01	1	−0.02
11. IMT	0.10	0.50***	0.23	0.26*	−0.04	−0.14	0.06	0.18	−0.10	−0.02	1

***p < 0.001, **p < 0.01, *p < 0.05; Cdist, carotid artery distensibility (%/10 mmHg); IMT, intima-media thickness (mm); BMI, body mass index (kg/m²); HDL, high-density lipoprotein (mmol/l); LDL, low-density lipoprotein (mmol/l); BP, blood pressure (mmHg).

^aGender coded so that higher values represent men.

Table 3. Interactive effects of HR, RSA and PEP reactivity and arterial elasticity on IMT.

	*df corrected model	df error	df	F	η^2	p value
HR reactivity × Cdist
Model 1	9	48		6.03	0.112	0.018
HR reactivity score			1	2.09	0.042	0.155
Cdist			1	7.13	0.129	0.010
Age			1	7.78	0.140	0.008
Gender			1	0.10	0.02	0.755
Model 2	15	42		2.48	0.056	0.123
Model 3	15	42		8.62	0.170	0.005
HR reactivity score			1	4.36	0.094	0.043
Cdist			1	2.03	0.046	0.162
Age			1	8.93	0.175	0.005
Gender			1	0.53	0.012	0.471
BMI			1	0.003	0.000	0.960
Insulin in plasma			1	0.16	0.004	0.690
Model 4	18	39		0.55	0.014	0.461
Model 5	30	27		1.67	0.058	0.207
RSA reactivity × Cdist
Model 1	9	48		6.10	0.113	0.017
RSA reactivity score			1	0.73	0.015	0.398
Cdist			1	5.80	0.108	0.020
Age			1	9.78	0.169	0.003
Gender			1	0.10	0.002	0.758
Model 2	15	42		2.68	0.060	0.109
Model 3	15	42		7.09	0.144	0.011
RSA reactivity score			1	1.62	0.037	0.210
Cdist			1	4.64	0.100	0.037
Age			1	8.55	0.169	0.006
Gender			1	0.32	0.008	0.571
BMI			1	1.07	0.025	0.306
Insulin in plasma			1	0.39	0.009	0.537
Model 4	18	39		0.001	0.000	0.980
Model 5	30	27		0.056	0.002	0.815
PEP reactivity × Cdist
Model 1	9	48		2.56	0.051	0.116
Model 2	15	42		0.64	0.015	0.428
Model 3	15	42		3.41	0.075	0.072
Model 4	18	39		1.01	0.025	0.320
Model 5	30	27		0.37	0.013	0.550

HR, heart rate (bpm); RSA, respiratory sinus arrhythmia (log ms²); PEP, pre-ejection period (ms); Cdist, carotid artery distensibility (%/10 mmHg); BMI, body mass index (kg/m²). Main effects were included in each analysis but they are presented for significant interactions only. Each interaction is examined in a separate analysis; Model 1: includes the main effects of gender, age, Cdist and the reactivity scores measure in question as well as interactive effects between reactivity and Cdist, Cdist and age/gender; reactivity and age/gender; Model 2: adjusted for BP and additionally includes the main effects of SBP and DBP as well as interactions between Cdist and BP; interactions between reactivity scores and BP; Model 3: adjusted for plasma insulin level and BMI and additionally includes the main effects of plasma insulin and BMI as well as interactions between Cdist and insulin level or BMI, interactions between reactivity scores and insulin level/BMI; Model 4: adjusted for lipoproteins and additionally includes the main effects of triglycerides, LDL and HDL cholesterols as well as interactions between Cdist and lipids levels, interactions between reactivity scores and lipids levels; Model 5: the fully adjusted model: adjusted for cardiovascular risk factors and additionally includes the main effects of LDL and HDL cholesterols, triglycerides, plasma insulin, BMI, SBP and DBP as well as interactions between Cdist and risk factors; interactions between reactivity scores and risk factors.

*df total = 58 (for all the models); df corrected total = 57 (for all the models).