Table 2.
Mean difference in rate of change in cognitive scores comparing tertiles of mean SBP, standard deviation, coefficient variation and variation independent of mean SBP (N=976)
| T1 | T2 | T3 | P-trend | |
|---|---|---|---|---|
| Global scores* mean change: −0.41 points/y | ||||
| Tertile of mean SBP | ||||
| <115.22 mm Hg | 115.22–128.76 mm Hg | ≥128.77 mm Hg | ||
| Model 1 | 0 (ref) | 0.09 (−0.10, 0.28) | 0.09 (−0.12, 0.29) | 0.43 |
| Model 2 | 0 (ref) | 0.09 (−0.10, 0.29) | 0.00 (−0.22, 0.22) | 0.99 |
| Tertile of Standard Deviation of SBP | ||||
| <9.30 mm Hg | 9.30–15.00 mm Hg | ≥15.01 mm Hg | ||
| Model 1 | 0 (ref) | −0.13 (−0.33, 0.06) | −0.24 (−0.43, −0.04) | 0.02 |
| Model 2 | 0 (ref) | −0.13 (−0.33, 0.06) | −0.27 (−0.47, −0.07) | 0.008 |
| Tertile of Coefficient of Variation of SBP | ||||
| <7.50% | 7.50–12.18% | ≥12.19% | ||
| Model 1 | 0 (ref) | −0.15 (−0.34, 0.05) | −0.31 (−0.51, −0.12) | 0.002 |
| Model 2 | 0 (ref) | −0.13 (−0.32, 0.06) | −0.31 (−0.50, −0.11) | 0.002 |
| Tertile of Variation Independent of Mean SBP | ||||
| <1.03% | 1.04–1.67% | ≥1.68% | ||
| Model 1 | 0 (ref) | −0.19 (−0.39, 0.00) | −0.28 (−0.47, −0.08) | 0.005 |
| Model 2 | 0 (ref) | −0.17 (−0.36, 0.02) | −0.27 (−0.47, −0.08) | 0.006 |
|
| ||||
| Composite scores* mean change: −0.062 SU/y | ||||
| Tertile of mean SBP | ||||
| Model 1 | 0 (ref) | 0.015 (−0.013, 0.043) | 0.010 (−0.020, 0.039) | 0.55 |
| Model 2 | 0 (ref) | 0.015 (−0.013, 0.043) | −0.001 (−0.033, 0.031) | 0.95 |
| Tertile of Standard Deviation of SBP | ||||
| Model 1 | 0 (ref) | −0.020 (−0.048, 0.008) | −0.034 (−0.062, −0.005) | 0.02 |
| Model 2 | 0 (ref) | −0.020 (−0.048, 0.008) | −0.038 (−0.066, −0.009) | 0.01 |
| Tertile of Coefficient of Variation of SBP | ||||
| Model 1 | 0 (ref) | −0.024 (−0.052, 0.004) | −0.045 (−0.073, −0.016) | 0.002 |
| Model 2 | 0 (ref) | −0.022 (−0.049, 0.006) | −0.044 (−0.072, −0.016) | 0.002 |
| Tertile of Variation Independent of Mean SBP | ||||
| Model 1 | 0 (ref) | −0.030 (−0.058, −0.002) | −0.040 (−0.068, −0.012) | 0.006 |
| Model 2 | 0 (ref) | −0.027 (−0.055, 0.001) | −0.039 (−0.067, −0.011) | 0.006 |
|
| ||||
| Verbal memory* mean change: −0.051 SU/y | ||||
| Tertile of mean SBP | ||||
| Model 1 | 0 (ref) | 0.008 (−0.025, 0.040) | 0.020 (−0.014, 0.054) | 0.25 |
| Model 2 | 0 (ref) | 0.008 (−0.024, 0.041) | 0.005 (−0.032, 0.042) | 0.79 |
| Tertile of Standard Deviation of SBP | ||||
| Model 1 | 0 (ref) | −0.017 (−0.050, 0.016) | −0.036 (−0.068, −0.003) | 0.03 |
| Model 2 | 0 (ref) | −0.018 (−0.051, 0.015) | −0.041 (−0.075, −0.008) | 0.02 |
| Tertile of Coefficient of Variation of SBP | ||||
| Model 1 | 0 (ref) | −0.013 (−0.045, 0.020) | −0.047 (−0.080, −0.014) | 0.004 |
| Model 2 | 0 (ref) | −0.010 (−0.043, 0.022) | −0.046 (−0.079, −0.013) | 0.006 |
| Tertile of Variation Independent of Mean SBP | ||||
| Model 1 | 0 (ref) | −0.020 (−0.052, 0.012) | −0.041 (−0.074, −0.008) | 0.01 |
| Model 2 | 0 (ref) | −0.017 (−0.049, 0.016) | −0.040 (−0.072, −0.007) | 0.02 |
Numbers in table are mean difference compared with tertile 1 (95% CI) unless otherwise specified. A negative β coefficient indicates faster rate of decline in cognitive performance. Model 1 adjusted for age, gender, education, time, and time interactions with each covariate. Model 2 additionally adjusted for urbanization index, ever smoking, physical activity, ever used antihypertensive treatment, mean SBP for variability analysis, and time interactions with each covariate.
Global score combined results of immediate recall of a 10-word list, delayed recall of a 10-word list, counting backward from 20, serial 7 subtraction, and orientation; Composite scores were computed by baseline z scores of memory scores and the rest of the cognitive scores, and were averaged into a single measure. Verbal memory score combined results of immediate and delayed recall of a 10-word list.