Analysis of the relationship between blood pressure variability and subtle cognitive decline in older adults

Table 1 General characteristics of participants

	NC (n = 237)	SCD (n = 182)	P value
Age, yr	70.35 ± 9.57	72.19 ± 10.31	0.002
Sex (male, %)	169 (71.31%)	127 (69.78%)	0.219
Education, yr	11.49 ± 4.12	10.05 ± 3.79	0.037
BMI (kg/m2)	22.47 ± 4.91	23.16 ± 5.03	0.291
Smoking, n (%)	51 (21.52)	39 (21.43)	0.479
Drinking, n (%)	72 (30.38)	57 (31.32)	0.517
Hypertension, n (%)	104 (43.88)	83 (45.60)	0.153
Diabetes, n (%)	35 (14.77)	31 (17.03)	0.021
CAD, n (%)	29 (12.24)	27 (14.84)	0.149
FBG (mmol/L)	5.41 ± 1.17	5.93 ± 1.61	0.037
PBG (mmol/L)	8.75 ± 2.81	8.59 ± 2.63	0.275
Scr (µmol/L)	82.45 ± 29.51	79.43 ± 28.72	0.117
TC (mmol/L)	4.53 ± 1.37	4.19 ± 0.95	0.093
TG (mmol/L)	1.32 ± 0.75	1.42 ± 0.81	0.055
HDL-C (mmol/L)	1.15 ± 0.51	1.17 ± 0.49	0.213
LDL-C (mmol/L)	2.39 ± 0.83	2.21 ± 0.79	0.314
SBP SD	10.52 ± 2.94	14.15 ± 4.37	0.000
DBP SD	7.32 ± 2.74	9.45 ± 3.07	0.040
SBP CV	12.35 ± 3.74	16.97 ± 4.91	0.000
DBP CV	9.85 ± 2.73	12.63 ± 3.81	0.006

NC: The control group; SCD: Subtle cognitive decline; BMI: Body mass index; CAD: Coronary artery disease; FBG: Fasting blood glucose; PBG: Postprandial blood glucose; Scr: Serum creatinine; TC: Total cholesterol; TG: Triglycerides; HDL-C: High-density lipoprotein cholesterol; LDL-C: Low-density lipoprotein cholesterol; SBP SD: 24-h systolic blood pressure standard deviation; SBP CV: 24-h systolic blood pressure coefficient of variation; DBP SD: 24-h diastolic blood pressure standard deviation; DBP CV: 24-h diastolic blood pressure variation coefficient.

Table 2 Scores of personnel cognition scale in two groups

Index	NC (n = 207)	SCD (n = 175)	F (P value)
MMSE	28.97 ± 2.13	26.15 ± 1.62	49.327 (< 0.001)
MoCA	25.74 ± 2.96	22.93 ± 3.27	57.319 (< 0.001)
AVLT recognition	21.39 ± 5.27	19.31 ± 3.77	3.572 (0.041)
AVLT delayed recall	6.32 ± 2.29	4.17 ± 1.59	8.351 (0.011)
BNT	24.15 ± 3.14	22.59 ± 3.57	0.275 (0.179)
SDMT	39.29 ± 12.57	34.26 ± 11.09	4.529 (0.032)
TMT-A	53.14 ± 23.95	57. 83 ± 26.71	0.127 (0.359)
TMT-B	133.49 ± 39.72	154.97 ± 45.21	5.273 (0.019)
Rey CFT copy	34.59 ± 3.71	31.49 ± 4.25	8.319 (0.014)
Rey CFT recall	16.72 ± 5.93	13.27 ± 6.41	9.592 (< 0.001)
AFT	16.79 ± 4.52	16.32 ± 4.17	0.035 (2.531)
PrM	14.31 ± 4.15	12.29 ± 4.52	3.572 (0.031)

NC: The control group; SCD: Subtle cognitive decline; MMSE: Mini-mental State Examination; MoCA: Montreal Cognitive Assessment; AVLT: Auditory Verbal Learning Test; BNT: Boston Naming Test; SDMT: Symbol Digit Modalities Test; TMTA, TMT-B: Trail Making Test Part A and B; Rey CFT: Rey-Osterrieth Complex Figure Text; AFT: Animal Fluency Test; PrM: Prospective Memory Test.

Table 3 Logistic regression analysis influencing factors of cognitive impairment

Index	β	SE	Wald	P value	OR	95%CI
Age	0.37	0.09	17.59	0.000	1.63	1.45-1.81
Education	0.75	0.13	20.31	0.000	1.92	1.75-2.31
Diabetes	0.11	0.03	13.27	0.000	1.21	1.09-1.37
SBP SD	1.31	0.24	26.15	0.000	3.95	2.57-4.72
SBP CV	0.95	0.21	30.63	0.000	3.71	2.69-4.63
DBP SD	2.47	0.61	8.59	0.023	9.72	3.51-18.95
DBP CV	0.85	0.19	27.33	0.002	3.01	2.65-3.91

SBP SD: 24-h systolic blood pressure standard deviation; SBP CV: 24-h systolic blood pressure coefficient of variation; DBP SD: 24-h diastolic blood pressure standard deviation; DBP CV: 24-h diastolic blood pressure coefficient of variation.

Table 4 Correlation between blood pressure variability and cognitive function by multivariate linear regression analysis

Outcome		Unadjusted model	P value	Adjusted model 1	P value	Adjusted model 2	P value
		β (95%CI)		β (95%CI)		β (95%CI)
Memory	SBP SD	-0.82 (-1.17 to -0.49)	< 0.001	-0.57 (-0.91 to -0.22)	< 0.001	-0.51 (-0.89 to -0.21)	< 0.001
	SBP CV	-0.79 (-1.15 to -0.42)	< 0.001	-0.61 (-0.93 to -0.32)	< 0.001	-0.59 (-0.91 to -0.25)	< 0.001
	DPB SD	-0.31 (-0.56 to -0.07)	< 0.05	-0.29 (-0.51 to -0.08)	0.029	-0.27 (-0.49 to -0.07)	0.035
	DPB CV	-0.27 (-0.55 to 0.01)	0.037	-0.26 (-0.47 to -0.08)	0.041	-0.23 (-0.41 to -0.03)	0.049
Language	SBP SD	0.04 (-0.02 to 0.09)	0.155	0.03 (-0.01 to 0.07)	0.165	0.03 (-0.02 to 0.09)	0.172
	SBP CV	0.04 (-0.01 to 0.11)	0.153	0.03 (-0.01 to 0.09)	0.167	0.03 (-0.02 to -0.10)	0.157
	DPB SD	0.11 (-0.01 to 0.23)	0.241	0.09 (0.02 to 0.19)	0.305	0.09 (0.01 to 0.18)	0.291
	DPB CV	0.08 (-0.02 to 0.17)	0.195	0.07 (-0.01 to 0.15)	0.236	0.07 (-0.02 to 0.16)	0.229
Attention	SBP SD	-0.76 (-1.07 to -0.39)	< 0.001	-0.67 (-1.03 to -0.21)	< 0.001	-0.70 (-1.01 to -0.39)	< 0.001
	SBP CV	-0.69 (-0.95 to -0.27)	< 0.001	-0.61 (-0.93 to -0.25)	< 0.001	-0.59 (-0.87 to -0.31)	< 0.001
	DPB SD	-0.17 (-0.35 to 0.02)	0.09	-0.11 (-0.32 to 0.01)	0.13	-0.12 (-0.31 to 0.02)	0.13
	DPB CV	-0.15 (-0.29 to -0.01)	0.08	-0.09 (-0.03 to 0.02)	0.15	-0.08 (-0.02 to 0.03)	0.17
Visuospatial ability	SBP SD	-0.27 (-0.39 to -0.14)	< 0.01	-0.21 (-0.35 to -0.10)	< 0.01	-0.20 (-0.33 to 0.06)	< 0.01
	SBP CV	-0.31 (-0.42 to -0.21)	< 0.01	-0.27 (-0.39 to -0.14)	< 0.01	-0.22 (-0.40 to -0.05)	< 0.01
	DPB SD	-0.11 (-0.25 to -0.03)	0.147	-0.07 (-0.02 to 0.03)	0.163	-0.06 (-0.02 to 0.01)	0.179
	DPB CV	-0.15 (-0.29 to 0.01)	0.133	-0.08 (-0.19 to 0.02)	0.182	-0.08 (-0.18 to 0.03)	0.195
Executive function	SBP SD	0.16 (0.05 to 0.28)	0.217	0.12 (-0.02 to 0.23)	0.327	0.11 (-0.01 to 0.27)	0.401
	SBP CV	0.15 (0.05 to 0.26)	0.195	0.11 (-0.01 to 0.21)	0.313	0.10 (0.01 to 0.0.21)	0.374
	DPB SD	0.23 (0.09 to 0.39)	0.291	0.19 (0.03 to 0.34)	0.307	0.17 (0.02 to 0.33)	0.351
	DPB CV	0.19 (0.03 to 0.37)	0.277	0.15 (0.04 to 0.27)	0.295	0.15 (0.04 to 0.29)	0.283
Social cognition	SBP SD	-0.06 (-0.10 to 0.02)	0.571	-0.04 (-0.12 to 0.07)	0.653	-0.03 (-0.11 to 0.06)	0.692
	SBP CV	-0.05 (-0.09 to 0.04)	0.612	-0.02 (-0.13 to 0.11)	0.713	0.01 (-0.14 to 0.13)	0.865
	DPB SD	0.17 (0.08 to 0.27)	0.187	0.14 (-0.03 to 0.31)	0.295	0.13 (-0.02 to 0.29)	0.312
	DPB CV	0.16 (0.04 to 0.29)	0.203	0.13 (-0.01 to 0.30)	0.323	0.12 (-0.02 to 0.27)	0.371

Unadjusted model: Random intercept for the study center. Adjusted model 1: Corrected for age, education, and diabetes. Adjusted model 2: Corrected for age, education, diabetes, body mass index, hypertension, coronary artery disease, smoking, drinking, blood lipids, and serum creatinine levels. SBP SD: 24-hsystolic blood pressure standard deviation; SBP CV: 24-h systolic blood pressure coefficient of variation; DBP SD: 24-h diastolic blood pressure standard deviation; DBP CV: 24-h diastolic blood pressure coefficient of variation.