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. 2017 Aug 31;7:10149. doi: 10.1038/s41598-017-09752-7

Table 2.

Univariate models.

Model Dependent variable Predictor b Bootstrap 95% CI se t p Zero- order Partial Semi- Partial VIF
1 SDBOLD brain score Age Group −0.89 (−1.16, −0.59) 0.14 −6.21 3.67 * 10 −8 −0.61 −0.60 −0.60 1.09
Absolute CBF 0.00 (−0.01, 0.01) 0.01 −0.44 0.66 0.13 −0.05 −0.04 1.09
2 SDBOLD brain score Age Group −0.69 (−1.09, −0.34) 0.17 −3.97 1.77 * 10 −4 −0.61 −0.43 −0.37 1.66
BOLD CVR 0.40 (−0.08, 0.80) 0.24 1.66 0.10 0.51 0.20 0.16 1.66
3 SDBOLD brain score Age Group −0.75 (−1.06, −0.43) 0.16 −4.73 1.16 * 10 −5 −0.61 −0.50 −0.45 1.37
M 0.24 (−0.12, 0.55) 0.16 1.49 0.14 0.44 0.18 0.14 1.37
4 SDBOLD brain score Age Group −0.67 (−1.03, −0.031) 0.19 −3.57 6.79 * 10 −4 −0.61 −0.40 −0.34 1.90
Absolute CBF 0.00 (−0.01, 0.01) 0.01 −0.39 0.70 0.13 −0.05 −0.04 1.15
BOLD CVR 0.29 (−0.21. 0.80) 0.27 1.08 0.28 0.51 0.13 0.10 2.01
M 0.17 (−0.24, 0.53) 0.17 0.99 0.33 0.44 0.12 0.09 1.64
5 CorrSD−CBF Age Group −0.05 (−0.12, 0.02) 0.04 −1.30 0.20 −0.16 n/a n/a n/a
6 CorrSD−CVR Age Group −0.10 (−0.17, −0.02) 0.04 −2.50 0.02 −0.29 n/a n/a n/a

Note: SD = standard deviation; CI = confidence interval; BOLD = blood oxygen level-dependent; YA = young adults; OA = older adults; CBF = cerebral blood flow; CVR = cerebrovascular reactivity; M = maximal BOLD signal change; VIF = variance inflation factor. Significant p-values are in bold font. “Zero-order”, “partial,” and “semi-partial” columns reflect effect sizes in Pearson’s correlation metric. Levene’s test for equality of variances was insignificant in all models (ps ranged from 0.12 to 0.95). Finally, the frequency of males and females was significantly different in the young (20 male, 8 female) and older (11 male, 32 female) groups (Chi square = 14.49, p = 1.41 * 10−4); however, sex had no predictive effect in any model reported above (all ps ranged from 0.21 to 0.52), and also had no appreciable effect on the unique effect of any predictor of interest. We thus report all final models above without further control for participant sex. Finally, there were no robust interactions between age group and any vascular parameter in Models 1–4 (all ps > 0.25).