Use of white blood cell counts to predict metabolic syndrome in the elderly: a 4 year longitudinal study

Figures & data

Figure 1. Study design.

Figure 2. Receiver-operating characteristic (ROC) analysis showing WBC level cutoff point (black square) used to predict metabolic syndrome in the study group. (a) Males. (b) Females.

Figure 3. Kaplan–Meier estimates of metabolic syndrome during follow-up according to the white blood cell levels predicting at baseline in validation group.

Table 1. Demographic data of the study group and validation group at baseline and follow-up.

		Follow-up
	Baseline	MetS (−)	MetS (+)	p
(a) Study group
Male
n	1754	1351	403
Age (years)	65.0 ± 5.1	68.8 ± 5.1	67.3 ± 5.7	<0.001
Body mass index (kg/m^2)	22.8 ± 2.5	22.5 ± 2.6	24.7 ± 2.3	<0.001
Waist circumference (cm)	81.4 ± 7.5	80.6 ± 7.3	88.7 ± 6.9	<0.001
Systolic blood pressure (mmHg)	125.8 ± 17.9	125.8 ± 17.9	137.0 ± 17.5	<0.001
Diastolic blood pressure (mmHg)	74.5 ± 10.6	72.4 ± 10.3	79.8 ± 10.5	<0.001
Fasting plasma glucose (mg/dl)	98.4 ± 12.8	100.9 ± 17.5	107.9 ± 19.6	<0.001
Total cholesterol (mg/dl)	200.4 ± 34.7	194.9 ± 33.6	197.7 ± 35.6	<0.001
HDL-C (mg/dl)	51.5 ± 12.9	57.1 ± 14.1	45.1 ± 12.1	<0.001
LDL-C (mg/dl)	127.8 ± 31.2	119.1 ± 30.2	121.7 ± 30.6	0.127
Triglyceride (mg/dl)	105.7 ± 48.7	93.5 ± 40.7	154.2 ± 61.3	<0.001
Log TG	2.0 ± 0.2	1.9 ± 0.2	2.2 ± 0.2	<0.001
WBC Count (10^3/μl)	6.0 ± 1.4	5.8 ± 1.3	6.3 ± 1.4	<0.001
Female
n	1674	1204	470
Age (years)	63.5 ± 4.0	67.2 ± 4.1	65.9 ± 4.5	<0.001
Body mass index (kg/m2)	23.2 ± 2.9	22.7 ± 2.7	25.0 ± 2.9	<0.001
Waist circumference (cm)	75.2 ± 7.2	74.1 ± 6.7	81.4 ± 7.2	<0.001
Systolic blood pressure (mmHg)	126.7 ± 17.7	127.7 ± 18.3	137.4 ± 15.8	<0.001
Diastolic blood pressure (mmHg)	72.5 ± 10.2	70.9 ± 10.2	77.2 ± 10.3	<0.001
Fasting plasma glucose (mg/dl)	96.7 ± 12.4	97.8 ± 11.8	104.9 ± 18.4	<0.001
Total cholesterol (mg/dl)	214.9 ± 37.5	211.1 ± 34.4	211.0 ± 37.1	0.964
HDL-C (mg/dl)	62.0 ± 14.4	68.1 ± 15.3	54.6 ± 13.8	<0.001
LDL-C (mg/dl)	131.6 ± 34.2	124.0 ± 31.8	126.6 ± 32.8	0.135
Triglyceride (mg/dl)	106.3 ± 44.6	95.0 ± 38.1	149.2 ± 61.0	<0.001
Log TG	2.0 ± 0.2	1.9 ± 0.2	2.1 ± 0.2	<0.001
WBC Count (10^3/μl)	5.7 ± 1.4	5.4 ± 1.3	5.9 ± 1.3	<0.001
(b) Validation group
Male
n	537	327	210
Age (years)	63.5 ± 4.8	66.9 ± 4.7	65.5 ± 5.2	0.002
Body mass index (kg/m^2)	23.6 ± 2.7	22.9 ± 2.3	25.0 ± 2.8	<0.001
Waist circumference (cm)	83.1 ± 7.5	81.4 ± 6.7	88.6 ± 7.6	<0.001
Systolic blood pressure (mmHg)	124.9 ± 18.0	123.4 ± 16.6	134.5 ± 15.0	<0.001
Diastolic blood pressure (mmHg)	74.5 ± 10.8	71.6 ± 9.7	78.7 ± 10.3	<0.001
Fasting plasma glucose (mg/dl)	102.4 ± 14.4	102.3 ± 13.5	108.9 ± 17.8	<0.001
Total cholesterol (mg/dl)	200.7 ± 33.1	195.7 ± 31.0	201.3 ± 31.5	0.042
HDL-C (mg/dl)	55.3 ± 12.8	56.4 ± 12.7	45.6 ± 10.4	<0.001
LDL-C (mg/dl)	123.8 ± 30.2	120.8 ± 27.4	125.1 ± 28.9	0.085
Triglyceride (mg/dl)	108.2 ± 50.3	92.8 ± 46.4	153.8 ± 55.6	<0.001
Log TG	2.0 ± 0.2	1.9 ± 0.2	2.2 ± 0.2	<0.001
WBC Count (10^3/μl)	6.0 ± 1.4	5.7 ± 1.3	6.0 ± 1.5	0.007
Female
n	574	330	244
Age (years)	62.5 ± 3.7	65.8 ± 3.3	64.8 ± 4.2	<0.001
Body mass index (kg/m^2)	23.4 ± 2.9	22.7 ± 2.7	24.7 ± 3.0	<0.001
Waist circumference (cm)	75.2 ± 7.0	73.8 ± 6.2	79.7 ± 7.0	<0.001
Systolic blood pressure (mmHg)	125.8 ± 17.1	123.7 ± 15.8	134.7 ± 17.4	<0.001
Diastolic blood pressure (mmHg)	71.6 ± 9.5	69.0 ± 9.6	76.3 ± 10.5	<0.001
Fasting Plasma Glucose (mg/dl)	99.7 ± 12.3	98.6 ± 8.9	104.8 ± 11.2	<0.001
Total cholesterol (mg/dl)	213.3 ± 35.2	213.1 ± 33.5	212.6 ± 36.1	0.867
HDL-C (mg/dl)	64.4 ± 14.9	65.4 ± 13.5	53.4 ± 13.8	<0.001
LDL-C (mg/dl)	126.7 ± 32.6	128.6 ± 31.1	127.4 ± 31.5	0.652
Triglyceride (mg/dl)	110.2 ± 51.8	95.6 ± 39.2	159.4 ± 63.8	<0.001
Log TG	2.0 ± 0.2	1.9 ± 0.2	2.2 ± 0.2	<0.001
WBC Count (10^3/μl)	5.7 ± 1.4	5.3 ± 1.2	5.6 ± 1.3	0.002

MetS (−), without metabolic syndrome; MetS (+), with metabolic syndrome; HDL-C, high-density lipoprotein cholesterol; LDL-C, Low-density lipoprotein cholesterol; Log TG, log transformation of triglyceride; WBC, white blood cell. Data are shown as mean ± SD.

Table 2. Univariate and multivariate analyses of baseline white blood cell levels and metabolic-related components at follow-up in the study group.

	Univariate		Multivariate
	γ	p	β	p
Male
Age	0.016	0.500	—	—
Waist circumference	0.112	<0.001	0.009	0.024
Systolic blood pressure	0.038	0.115	—	—
Diastolic blood pressure	0.013	0.580	—	—
Fasting plasma glucose	0.047	0.047	0.003	0.081
HDL-C	−0.144	<0.001	−0.008	0.001
LDL-C	0.075	0.002	0.002	0.044
Triglyceride	0.173	<0.001	0.003	0.000
Female
Age	0.008	0.758	—	—
Waist circumference	0.097	<0.001	0.010	0.150
Systolic blood pressure	0.097	<0.001	0.007	0.094
Diastolic blood pressure	0.079	0.001	0.008	<0.001
Fasting plasma glucose	0.081	0.001	−0.003	0.412
HDL-C	−0.146	<0.001	0.007	0.002
LDL-C	0.057	0.020	−0.005	0.011
Triglyceride	0.205	<0.001	0.001	0.103

HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol.

Table 3. Cox regression between baseline variables, white blood cell levels, and components of MetS and whether subjects had MetS after follow-up.

	Hazard ratio	p Value
(a) Study group
Male
White blood cell (>5.7 10^3/µl)	1.602 (1.277–2.011)	<0.001
Waist circumference (≥90 cm)	2.631 (1.951–3.548)	<0.001
Blood pressure (SBP ≥ 130 or DBP ≥ 85 mmHg)	2.022 (1.615–2.533)	<0.001
Fasting plasma glucose (≥100 mg/dl)	1.214 (0.964–1.528)	<0.001
Triglyceride (≥150 mg/dl)	2.229 (1.650–3.012)	<0.001
High-density lipoprotein (<40 mg/dl)	2.801 (2.094–3.748)	<0.001
Female
White blood cell (>5.0 10^3/µl)	1.923 (1.515–2.441)	<0.001
Waist circumference (≥80 cm)	3.049 (2.381–3.904)	<0.001
Blood pressure (SBP ≥ 130 or DBP ≥ 85 mmHg)	1.380 (1.114–1.711)	0.003
Fasting plasma glucose (≥100 mg/dl)	1.351 (1.065–1.713)	0.013
Triglyceride (≥150 mg/dl)	2.135 (1.564–2.913)	<0.001
High-density lipoprotein (<50 mg/dl)	2.255 (1.731–2.937)	<0.001
(b) Validation group
Male
White blood cell (>5.7 10^3/µl)	1.351 (0.953–1.916)	0.091
Waist circumference (≥90 cm)	5.545 (3.277–9.385)	<0.001
Blood pressure (SBP ≥ 130 or DBP ≥ 85 mmHg)	1.564 (1.093–2.237)	0.014
Fasting plasma glucose (≥100 mg/dl)	1.275 (0.900–1.806)	0.172
Triglyceride (≥150 mg/dl)	3.570 (2.065–6.171)	<0.001
High-density lipoprotein (<40 mg/dl)	2.827 (1.391–5.744)	0.004
Female
White blood cell (>5.0 10^3/µl)	1.923 (1.341–2.756)	<0.001
Waist circumference (≥80 cm)	4.725 (3.024–7.382)	<0.001
Blood pressure (SBP ≥ 130 or DBP ≥ 85 mmHg)	1.605 (1.141–2.260)	0.007
Fasting plasma glucose (≥100 mg/dl)	1.778 (1.265–2.499)	0.001
Triglyceride (≥150 mg/dl)	2.411 (1.465–3.968)	0.001
High-density lipoprotein (<50 mg/dl)	2.937 (1.720–5.013)	<0.001

Table 4. The κ coefficient test between predicted and observed metabolic syndrome in the validation group.

	Observed MetS at follow-up
	MetS (−)	MetS (+)	κ	p
Male
Predicted MetS by WBC
MetS (−)	163	89	0.078	0.089
MetS (+)	164	121
Female
Predicted MetS by WBC
MetS (−)	134	64	0.110	<0.001
MetS (+)	196	180

MetS, metabolic syndrome; MetS (−), without metabolic syndrome; MetS (+), with metabolic syndrome; WBC, white blood cell.