Table 2.

Risk of cognitive impairment by systolic/diastolic blood pressure level

	HR [95% CI] for mild/moderate/severe cognitive impairment (MMSE<24)			HR [95% CI] for moderate/severe cognitive impairment (MMSE<18)
	Unadjusted model	Basic model †	Fully adjusted model ‡	Unadjusted model	Basic model †	Fully adjusted model ‡
SBP
No. of participants	12,271	12,241	11,946	12,271	12,241	11,946
No. of events	4,413	4,401	4,280	2,092	2,089	2,034
No. of person years	61,805.7	61,672.9	60,446.1	66,619.9	66,472.8	65,167.7
<110 mmHg	1.21[1.04, 1.41]*	1.10[0.94, 1.28]	1.11[0.95, 1.30]	1.45[1.17, 1.79]***	1.32[1.06, 1.63]*	1.32[1.06, 1.64]*
110–119 mmHg	1.02[0.90, 1.15]	1.06[0.94, 1.20]	1.07[0.94, 1.21]	0.96[0.80, 1.17]	1.02[0.85, 1.24]	1.03[0.85, 1.25]
120–129 mmHg	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)
130–139 mmHg	1.19[1.08, 1.30]***	1.17[1.06, 1.28]***	1.17[1.07, 1.29]***	1.25[1.09, 1.44]**	1.22[1.06, 1.40]**	1.23[1.07, 1.42]**
140–149 mmHg	1.26[1.14, 1.39]***	1.21[1.10, 1.34]***	1.21[1.10, 1.34]***	1.26[1.09, 1.45]**	1.18[1.02, 1.36]*	1.19[1.03, 1.38]*
150–159 mmHg	1.37[1.22, 1.54]***	1.22[1.09, 1.37]***	1.24[1.10, 1.39]***	1.48[1.25, 1.74]***	1.29[1.09, 1.51]**	1.30[1.10, 1.54]**
160–169 mmHg	1.50[1.32, 1.69]***	1.27[1.12, 1.44]***	1.29[1.13, 1.46]***	1.51[1.26, 1.81]***	1.22[1.01, 1.46]*	1.22[1.01, 1.47]*
170–179 mmHg	1.75[1.50, 2.05]***	1.33[1.14, 1.55]***	1.34[1.14, 1.56]***	2.14[1.73, 2.64]***	1.52[1.23, 1.88]***	1.58[1.27, 1.96]***
>180 mmHg	2.01[1.77, 2.28]***	1.48[1.30, 1.69]***	1.54[1.35, 1.75]***	2.24[1.87, 2.69]***	1.57[1.31, 1.89]***	1.62[1.35, 1.96]***
P-trend	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
DBP
No. of participants	12,258	12,228	11,934	12,258	12,228	11,934
No. of events	4,408	4,396	4,276	2,091	2,088	2,033
No. of person years	61,730.8	61598	60,375.3	66,541.9	66,394.8	65,093.7
<70 mmHg	0.94[0.83, 1.06]	0.83[0.73, 0.94]**	0.84[0.74, 0.96]**	1.12[0.94, 1.33]	0.98[0.82, 1.16]	0.99[0.83, 1.18]
70–79 mmHg	1.03[0.95, 1.11]	0.98[0.90, 1.06]	0.97[0.89, 1.05]	1.07[0.95, 1.21]	1.01 [0.89, 1.13]	1.00[0.88, 1.12]
80–89 mmHg	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)	1.00(referent)
90–99 mmHg	1.10[1.02, 1.19]*	1.09[1.01, 1.18]*	1.09[1.01, 1.18]*	1.18[1.05, 1.32]**	1.15[1.02, 1.28]*	1.12[1.00, 1.26]*
100–109 mmHg	1.30[1.16, 1.47]***	1.21[1.08, 1.37]***	1.20[1.06, 1.35]**	1.38[1.16, 1.63]***	1.21[1.01, 1.43]*	1.18[0.99, 1.41]
>110 mmHg	1.16[1.00, 1.35]*	1.20[1.04, 1.39]*	1.19[1.02, 1.38]*	1.25[1.01, 1.54]*	1.31[1.06, 1.62]*	1.25[1.01, 1.56]*
P-trend	<0.001	<0.001	<0.001	0.01	0.001	0.003

The results were based on regular cox regression taking SBP/DBP level as a categorical variable in the model.

^†Basic model: adjusted for age, sex, education, co-residence, and residence;

^‡Fully adjusted model: additionally adjusted for smoking, drinking, frequent vegetable consumption, frequent fruit consumption, frequent physical activity, impaired activity of daily living, obesity, activities of daily living, self-reported diabetes mellitus, self-reported heart disease, and self-reported cerebrovascular disease.

HR: hazard ratio; CI: confidence interval; MMSE: mini-mental state examination; SBP: systolic blood pressure; DBP: diastolic blood pressure.

^*0.01 ≤ P < 0.05

^**0.001 ≤ P < 0.01

^***P < 0.001

HR: hazard ratio; CI: confidence interval; MMSE: mini-mental state examination; SBP: systolic blood pressure; DBP: diastolic blood pressure.