Table 4.
Relationships between menopausal status and NVC.
| NVC parameters | Model |
Coefficients |
||||||
|---|---|---|---|---|---|---|---|---|
| P-value | R2 | Early post-menopausal (57.0 ± 5.9 years, N = 7) |
Late post-menopausal (66.6 ± 3.7 years, N = 13) |
Age (49.5 ± 16.4 years, N = 34) |
||||
| β | P | β | P | β | P | |||
| Baseline parameters | ||||||||
| PCAv (cm/s) | 0.02 | 0.16 | 0.8 ± 4.7 | 0.87 | −7.4 ± 3.6 | 0.041 | −0.09 ± 0.09 | 0.27 |
| MAP (mmHg) | <0.001 | 0.21 | 6.6 ± 4.9 | 0.19 | 5.0 ± 3.8 | 0.19 | 0.3 ± 0.1 | 0.001 |
| CVRi (mmHg/cms−1) | <0.001 | 0.35 | 0.11 ± 0.29 | 0.71 | 0.69 ± 0.23 | 0.004 | 0.01 ± 0.01 | 0.001 |
| CVC (cms−1/mmHg) | 0.001 | 0.27 | −0.02 ± 0.06 | 0.75 | −0.09 ± 0.04 | 0.06 | −0.003 ± 0.01 | 0.02 |
| PETCO2 (mmHg) | 0.16 | 0.08 | 4.7 ± 2.6 | 0.17 | 3.1 ± 2.0 | 0.13 | −0.08 ± 0.05 | 0.09 |
| HR (bpm) | 0.81 | 0.016 | 2.6 ± 3.9 | 0.51 | 1.5 ± 3.0 | 0.62 | 0.01 ± 0.07 | 0.85 |
| Peak parameters | ||||||||
| PCAv (cm/s) | 0.02 | 0.15 | 1.7 ± 5.1 | 0.74 | −8.7 ± 3.9 | 0.04 | −0.11 ± 0.09 | 0.23 |
| MAP (mmHg) | 0.20 | 0.07 | 9.8 ± 6.2 | 0.12 | 6.7 ± 4.8 | 0.17 | 0.01 ± 0.1 | 0.97 |
| CVRi (cms−1/mmHg) | <0.001 | 0.34 | 0.09 ± 0.30 | 0.77 | 0.69 ± 0.24 | 0.005 | 0.01 ± 0.005 | 0.03 |
| CVC | 0.002 | 0.27 | −0.02 ± 0.06 | 0.80 | −0.09 ± 0.05 | 0.07 | −0.01 ± 0.001 | 0.01 |
| Relative PCAv (Δ%) | 0.67 | 0.03 | 0.90 ± 4.1 | 0.83 | 3.7 ± 3.2 | 0.25 | −0.02 ± 0.07 | 0.79 |
| PCAv AUC (AU) | 0.94 | 0.007 | 1.9 ± 31.7 | 0.95 | 9.5 ± 24.6 | 0.70 | −0.36 ± 0.57 | 0.54 |
| Time to peak (s) | 0.23 | 0.07 | −4.7 ± 3.7 | 0.20 | 0.69 ± 2.8 | 0.81 | 0.09 ± 0.07 | 0.20 |
| HR (bpm) | 0.85 | 0.01 | −0.11 ± 6.1 | 0.99 | 3.9 ± 4.7 | 0.41 | −0.03 ± 0.11 | 0.82 |
| Kinetic parameters | ||||||||
| PCAv τ (s) | 0.59 | 0.05 | 0.71 ± 2.7 | 0.79 | −1.8 ± 1.6 | 0.28 | 0.05 ± 0.04 | 0.24 |
| PCAv Amp Δ (cm/s) | 0.22 | 0.11 | 1.8 ± 1.9 | 0.14 | −1.3 ± 1.2 | 0.26 | 0.02 ± 0.03 | 0.57 |
| PCAv TD (s) | 0.14 | 0.16 | 1.8 ± 2.1 | 0.40 | 3.0 ± 1.3 | 0.03 | −0.07 ± 0.04 | 0.07 |
Data presented as mean ± SD. Multiple linear regression investigating the influence of menopausal status on baseline and peak NVC responses. Model coefficients investigate the relationship between early post-menopause (1–3 years), and late post-menopause (6+ years) to a reference group of pre-menopausal women (34.0 ± 10.2 years) on the variables of interest. Age was added to the model to account for any variance explained by differences in age between groups. For variable of age, model coefficients represent the change in variable units for every year increase in age. Bold indicated significant relationship (P < 0.05). β-coefficients for early post-menopausal and late post-menopausal females are presented compared to reference group of premenopausal females. PCAv: posterior cerebral artery velocity; AUC: area under the curve; Amp: amplitude; τ: time constant; TD: time delay; CVRi: cerebrovascular resistance index; CVC: cerebrovascular conductance index; MAP: mean arterial pressure; PETCO2: end-tidal carbon dioxide; HR: heart rate.