Table 2.

Correlates of Overall Systolic Variability in 2944 Participants

Label	Variability Independent of the Mean (units)	Difference Between Maximum and Minimum Blood Pressure (mm Hg)	Average Real Variability (mm Hg)
Variance explained
Total	0.138	0.306	0.403
Pedigree	0.117	0.150	0.226
Fixed effects	0.021	0.157	0.178
Parameter estimates (SE)
Female sex	−0.245 (0.102)^*	—	—
Age, +10 y	0.205 (0.038)^§	0.658 (0.105)^§	0.138 (0.025)^§
Body mass index, +5 kg/m²	−0.208 (0.064)^†	−0.630 (0.178)^‡	−0.116 (0.043)^†
Systolic blood pressure, +10 mm Hg	−0.077 (0.039)^*	1.787 (0.105)^§	0.347 (0.025)^§
Heart rate, +5 bpm	—	—	0.054 (0.019)^†
Total/high-density lipoprotein cholesterol, +1 unit	—	−0.164 (0.086)^*	−0.104 (0.021)^§
Plasma glucose, +1 mmol/L	—	—	0.066 (0.026)^*
Serum creatinine, +10 μmol/L	—	−0.246 (0.083)^†	—
Peripheral arterial disease	1.254 (0.492)^*	3.538 (1.338)^†	—
Treated with β-blockers	0.494 (0.209)^*	1.425 (0.567)^*	—

Systolic blood pressure was based on 10 blood pressure readings, that is, 5 consecutive blood pressure readings at each of 2 home visits at an interval of 2 to 4 weeks. The following variables were not related to any index of variability: energy expenditure in physical activity, triglycerides, history of cardiovascular disease, smoking and alcohol intake, diabetes mellitus, and classes of antihypertensive drugs other than β-blockers.

Significance of the parameter estimates:

P≤0.05;

^†

P≤0.01;

^‡

P≤0.001; and

^§

P≤0.0001.