Inverse relationship between vitamin D levels and platelet indices in Korean adults

Figures & data

Table 1. Characteristics of subjects according to deficiency, insufficiency, and sufficiency of vitamin D.^a

	Vitamin D group^b
	Deficiency (n = 961)	Insufficiency (n = 1896)	Sufficiency (n = 333)	P-value
Age (y)	45.0 ± 9.2	45.0 ± 8.9	47.6 ± 9.5	<0.001
Female gender (%)	47.1	21.5	15.0	<0.001
Body mass index (kg/m^2)	24.1 ± 3.3	24.6 ± 3.1	23.9 ± 2.6	0.001
Waist circumference (cm)	85.1 ± 8.9	86.8 ± 8.1	85.1 ± 7.2	0.002
Current smoker (%)	31.3	36.8	30.0	0.008
Alcohol ingestion (%)	30.8	38.9	38.3	<0.001
Regular exercise (%)	34.5	44.7	42.6	<0.001
SBP (mmHg)	120.6 ± 15.2	120.6 ± 15.0	119.4 ± 14.4	0.343
DBP (mmHg)	78.8 ± 11.1	78.9 ± 11.1	77.4 ± 11.2	0.045
Fasting glucose (mg/dl)	98.1 ± 23.3	97.3 ± 21.6	94.9 ± 13.2	<0.001
Total cholesterol (mg/dl)	203.4 ± 37.5	201.1 ± 34.9	199.3 ± 35.3	0.120
HDL cholesterol (mg/dl)	59.5 ± 15.4	59.0 ± 14.7	61.9 ± 15.7	<0.001
Triglycerides^c (mg/dl)	151.6 ± 100.1	133.8 ± 77.1	102.5 ± 54.3	<0.001
WBC (10^3 cells/μl)	5.7 ± 1.4	5.6 ± 1.4	5.4 ± 1.3	0.002
Hemoglobin (g/dl)	14.6 ± 1.4	15.0 ± 1.2	15.1 ± 1.1	0.020
CRP^c (mg/l)	0.1 ± 0.3	0.1 ± 0.2	0.1 ± 0.2	0.074
Diabetes^d (%)	7.8	7.3	4.5	0.122
Hypertension^e (%)	29.2	29.8	29.9	0.607
Vitamin D (ng/ml)	8.1 ± 1.4	14.0 ± 2.7	24.8 ± 4.5	<0.001
Platelets (10^3/μl)	261.5 ± 51.2	249.8 ± 47.6	246.9 ± 47.4	<0.001
Mean platelet volume (fl)	8.5 ± 0.8	8.4 ± 0.8	8.3 ± 0.8	0.028

SBP: systolic blood pressure; DBP: diastolic blood pressure; HDL: high-density lipoprotein; CRP: C-reactive protein; WBC: white blood cell.

^aData are expressed as mean ± SD, or percentage.

^bVitamin D deficiency, insufficiency, and sufficiency were defined as <10.0, 10.0–20.0, and >20.0 ng/ml, respectively.

^cLog transformed values were used for comparison.

^dDiabetes was defined as a history of taking antidiabetic medication or FBG level ≧ 126 mg/dl.

^eHypertension was defined as a history of taking antihypertensive medication or systolic blood pressure (SBP) ≧ 140 mmHg, diastolic blood pressure (DBP) ≧ 90 mmHg.

Figure 1. Platelet count according to vitamin D groups. P-values were calculated by ANOVA: platelet count was 261.5±51.2×10³/μL in 25(OH)D deficiency, 249.8±47.6×10³/μL in 25(OH)D insufficiency, 246.9±47.4× 10³/μL in 25(OH)D sufficiency.

Figure 2. Mean platelet volume according to vitamin D groups. P-values were calculated by ANOVA: mean platelet volume was 8.5±0.8fL in 25(OH)D deficiency, 8.4±0.8fL in 25(OH)D insufficiency, 8.3±0.8fL in 25(OH)D sufficiency.

Figure 3. The expected inverse relationship between platelet count and mean platelet volume. P-value was calculated by Pearson’s correlation.

Table 2. Correlations between platelet indices and continuous variables (Pearson’s correlation).

	Platelet count		Mean platelet volume
	r	P-value	r	P-value
Age	−0.004	0.040	0.005	0.799
Body mass index	0.032	0.074	−0.024	0.168
SBP	−0.026	0.138	0.026	0.149
DBP	−0.019	0.283	0.004	0.813
WBC	0.241	<0.001	0.008	0.637
Hemoglobin	−0.114	<0.001	−0.052	0.003
Creatinine	−0.121	<0.001	0.024	0.169
Fasting glucose	0.005	0.770	−0.023	0.193
Total cholesterol	0.123	<0.001	−0.064	<0.001
HDL cholesterol	−0.010	0.577	−0.006	0.723
Log (triglycerides)	0.072	<0.001	−0.021	0.247
Log (CRP)	0.108	<0.001	−0.009	0.630

SBP: systolic blood pressure; DBP: diastolic blood pressure; WBC: white blood cell; HDL: high-density lipoprotein; CRP: C-reactive protein.

Table 3. Correlations between platelet indices and nominal variables (t-tests).

		Platelet count		Mean platelet volume
		Mean ± SD	P-value	Mean ± SD	P-value
Gender	M	249.44 ± 48.44	<0.001	8.40 ± 0.81	0.869
	F	262.20 ± 49.47		8.41 ± 0.85
Current smoker	Y	253.01 ± 49.05	0.495	8.40 ± 0.82	0.706
	N	251.65 ± 48.07		8.40 ± 0.81
Alcohol ingestion	Y	254.15 ± 49.88	0.177	8.41 ± 0.83	0.352
	N	251.41 ± 48.47		8.38 ± 0.82
Regular exercise	Y	248.52 ± 47.12	<0.001	8.43 ± 0.80	0.030
	N	256.20 ± 49.77		8.37 ± 0.84
Diabetes^a	Y	253.57 ± 50.63	0.874	8.35 ± 0.78	0.338
	N	253.04 ± 48.95		8.41 ± 0.83
Hypertension^b	Y	253.04 ± 49.23	0.973	8.44 ± 0.84	0.088
	N	253.10 ± 49.01		8.39 ± 0.82

^aDiabetes was defined as a history of taking antidiabetic medication or FBG level ≧126 mg/dL.

^bHypertension was defined as a history of taking antihypertensive medication or systolic blood pressure (SBP) ≧ 140 mmHg, diastolic blood pressure (DBP) ≧ 90 mmHg.

Table 4. Multiple linear regression analyses showing the independent contribution of vitamin D group to platelet count.

	Platelet count
	Β	P-value
Model 1^a	−8.711	<0.001
Model 2^b	−6.559	<0.001
Model 3^c	−3.461	<0.022

^aNot Adjusted.

^bAdjusted for sex and age.

^cAdjusted for sex, age, regular exercise, WBC, total cholesterol, hemoglobin, creatinine, CRP.

Table 5. Multiple linear regression analyses showing the independent contribution of vitamin D group to mean platelet volume.

	Mean platelet volume
	β	P-value
Model 1^a	−0.085	<0.001
Model 2^b	−0.080	0.002
Model 3^c	−0.082	0.002

^aNot Adjusted.

^bAdjusted for regular exercise, hemoglobin, total cholesterol.

^cAdjusted for regular exercise, hemoglobin, total cholesterol, diabetes, hypertension, BMI.