B-type natriuretic peptide as a predictor of declining cognitive function and dementia—a cohort study of an elderly general population with a 5-year follow-up

Figures & data

Figure 1. Flow chart of the study.

Table I. Base-line characteristics and drug treatment in all participants (n = 464) according to their B-type natriuretic peptide (BNP) tertiles.

	BNP pmol/L
	<23.5	23.5–53.7	>53.7	P-value
Characteristics:
Age, mean (SD)	78.6 (3.4)	79.8 (4.2)	81.3 (4.6)	<0.001
Women, %	71.9	70.8	74.2	NS
Body mass index, mean (SD)	27.3 (4.3)	26.4 (4.5)	25.7 (4.0)	0.007
MMSE, median (IQR)	27 (25–29)	28 (25–29)	26 (24–29)	0.014
MMSE <24 points, %	13.7	18.2	23.2	NS
education in years, mean (SD)	6.8	7.1	7.1	NS
Zung's depression scale, mean (SD)	38.8 (8.6)	39.1 (7.3)	40.2 (8.0)	NS
Medication:
Regular medication, %	84.3	88.3	96.7	0.001
Beta-blocker, %	28.1	40.9	64.9	<0.001
ACE inhibitors/ARBs, %	15.0	17.5	29.8	0.003
Diuretics, %	34.0	24.0	47.7	<0.001
Ca-channel blockers, %	19.0	20.1	14.6	NS
Statins, %	3.9	7.1	3.3	NS
Oral diabetes medication, %	5.9	7.1	9.3	NS
Insulin, %	3.3	3.9	4.0	NS
Previous illnesses:
Myocardial infarction, %	26.8	35.7	34.4	NS
Hypertension, %	58.2	63.6	62.3	NS
Heart failure, %	14.4	16.2	43.0	<0.001
Atrial fibrillation, %	3.9	10.4	31.1	<0.001
Diabetes, %	21.6	15.6	24.5	NS
Stroke, %	6.5	7.1	17.2	0.014
Smoking:
Non-smoker, %	69.9	74.0	77.5	NS
Ex-smoker, %	23.5	23.4	17.2	NS
Smoker, %	6.5	7.9	4.6	NS
Blood pressure, systolic, mean (SD)	151.9 (22.8)	157.1 (24.3)	149.9 (25.0)	0.026
Blood pressure, diastolic, mean (SD)	78.5 (9.54)	77.6 (10.2)	73.7 (11.8)	0.037
Laboratory data:
Haemoglobin, mean (SD) g/L	135.2 (12.6)	133.6 (11.8)	131.7 (13.5)	NS
Cr-Cl, mean (SD) mL/min	56.4 (15.1)	54.8 (16.3)	47.2 (13.3)	<0.001
FP-gluc, mean (SD) mmol/L	5.7 (1.34)	5.5 (1.13)	5.7 (1.52)	NS
Lipids:
Total cholesterol, mean (SD) mmol/L	5.90 (1.21)	5.73 (1.18)	5.45 (1.21)	0.005
LDL-cholesterol, mean (SD) mmol/L	4.08 (1.06)	3.89 (1.02)	3.74 (1.02)	NS
HDL-cholesterol, mean (SD) mmol/L	1.46 (0.40)	1.56 (0.40)	1.41 (0.43)	0.009
Trigly, median (IQR) mmol/L	1.47 (1.0–2.0)	1.25 (0.9–1.6)	1.29 (1.0–1.8)	0.038

To convert lipids to mg/dL, multiply by 38.6.MMSE = Mini Mental State Examination score; SD = standard deviation; ACE = angiotensin-converting enzyme; ARB = angiotensin II receptor blocker; Cr-Cl = creatinine clearance; fP-gluc = fasting plasma glucose; LDL = low-density lipoprotein; HDL = high-density lipoprotein; trigly = triglycerides.

Table II. Associations of clinical variables with base-line MMSE, decline of MMSE and new cases of dementia in 5-year follow-up.

	Base-line MMSE		Decline of MMSE		New dementia cases
	beta	P-value	beta	P-value	OR and (95% CI) per 1 SD increase	P value
Age	−0.335	<0.001	0.056	0.348	1.51 (1.14–2.11)	0.006
Sex	0.077	0.100	0.035	0.562	0.82 (0.42–1.58)	0.547
Body mass index	−0.018	0.696	−0.011	0.861	0.96 (0.72–1.30)	0.748
Education in years	0.392	<0.001	0.006	0.921	0.48 (0.32–0.75)	<0.001
Smoking	0.088	0.060	−0.009	0.878	2.07 (0.96–4.44)	0.062
NYHA class I–II versus III-IV^a	−0.177	<0.001	0.040	0.506	0.95 (0.46–1.96)	0.883
Hypertension	0.032	0.490	−0.049	0.415	0.50 (0.28–0.89)	0.019
Previous heart failure	−0.141	0.002	−0.012	0.847	1.25 (0.62–2.51)	0.528
Atrial fibrillation	−0.081	0.083	0.115	0.053	1.96 (0.90–4.24)	0.089
Diabetes	0.020	0.664	0.025	0.672	0.49 (0.21–1.13)	0.094
Previous stroke	−0.149	0.001	0.036	0.549	1.01 (0.41–2.51)	0.982
Heart rate	−0.127	0.006	−0.107	0.071	0.87 (0.58–1.14)	0.237
Haemoglobin	0.125	0.007	−0.071	0.234	0.77 (0.60–1.13)	0.137
Creatinine clearance	0.182	<0.001	−0.075	0.207	0.73 (0.53–1.00)	0.071
Cholesterol	0.067	0.151	0.070	0.242	1.13 (0.84–1.52)	0.411
LDL-cholesterol	0.020	0.664	0.082	0.171	1.16 (0.87–1.54)	0.322
HDL-cholesterol	0.174	<0.001	−0.015	0.802	0.96 (0.72–1.29)	0.798
Triglycerides	−0.079	0.091	0.036	0.551	1.06 (0.78–1.44)	0.710
B-type natriuretic peptide	−0.151	0.001	0.140	0.019	1.55 (1.13–2.12)	0.007
Systolic blood pressure	0.060	0.197	−0.056	0.348	1.00 (0.61–1.27)	0.499
Diastolic blood pressure	0.085	0.070	−0.062	0.297	0.80 (0.58–1.00)	0.071
Base-line MMSE	–	–	0.007	0.906	0.34 (0.23–0.89)	<0.001

Smoking was reclassified as non-smokers versus others.

^aNYHA class III—IV compared with I—II, participants with higher NYHA class had lower base-line MMSE.

MMSE = Mini-Mental State Examination; beta = standardized regression coefficient; OR = adjusted odds ratio; CI = 95% confidence interval; SD = standard deviation; NYHA = New York Heart Association; LDL = low-density lipoprotein; HDL = high-density lipoprotein.

Table III. Multivariable logistic regression model presenting adjusted odds ratios and 95% confidence intervals per 1 SD increase of clinical variables for the association with future dementia. The model on the left includes the variables significant in Table II. The model on the right is similar but also adjusted with the base-line MMSE.

	OR (95% CI)	P-value	MMSE adjusted OR (95% CI)	P-value
Age	1.30 (0.89–1.88)	0.172	1.28 (0.73–1.60)	0.180
Hypertension	0.53 (0.27–0.95)	0.034	0.52 (0.27–1.00)	0.050
Education in years	0.50 (0.33–0.77)	0.001	0.69 (0.44–1.07)	0.100
B-type natriuretic peptide	1.53 (1.09–2.16)	0.016	1.46 (1.03–2.09)	0.030

CI = confidence interval; MMSE = Mini-Mental State Examination score; OR = odds ratio.

Figure 2. Box plots for B-type natriuretic peptide of the participants. Participants divided to groups according to their follow-up visit dementia status. Participants with no dementia (n = 230) BNP = mean 39.3 (SD 37.2) pg/mL, Alzheimer's disease (n = 42) BNP = 56.9 (57.6) pg/mL, vascular dementia (n = 10) BNP = 79.6 (56.7) pg/mL. ANOVA P = 0.001 in between the groups.