Table 2.

Selected characteristics [medians (interquartile range) or percent] by quartile of circulating vitamin D binding protein concentration in the CPS-II cohort

Characteristic	Q1 (<272 μg/mL)	Q2 (272 – <294 μg/mL)	Q3 (294 – <334 μg/mL)	Q4 (≥ 334 μg/mL)	p-value*
Age (years)	71.6 (66.1 – 75.9)	72.5 (68.3 – 76.0)	70.1 (65.4 – 74.9)	67.8 (64.0 – 73.8)	0.06
Male (%)	74.0	72.6	64.1	38.2	0.003
Race (%)
White	96.0	98.0	97.4	100.0	0.69
BMI‡ (kg/m2)	27.3 (23.6 – 29.6)	24.8 (23.0 – 27.4)	25.1 (22.1 – 27.5)	25.4 (23.2 – 28.2)	0.09
Smoking Status‡ (%)
Never	37.0	42.2	36.8	53.1	0.52
Former	63.0	55.6	57.9	43.8
Current	0.0	2.2	5.3	3.1
History of diabetes‡ (%)	22.0	13.7	12.8	2.9	0.10
History of kidney failure† (%)	0	0	0	2.9	0.25
Physically active‡ (MET-hrs/week)	14.0 (7.0 – 26.5)	14.0 (7.0 – 24.5)	14.0 (7.0 – 24.0)	13.9 (7.0 – 29.0)	0.89
College graduate† (%)	62.0	51.0	38.5	45.5	0.77
Intake/day‡
Total energy (kcal)	1 881 (1 445 – 2 254)	1 842 (1 538 – 2 159)	1 719 (1 378 – 2 082)	1 628 (1 495 – 2 137)	0.56
Dietary vitamin D (IU)	178 (141 – 283)	183 (114 – 303)	167 (125 – 283)	188 (160 – 220)	0.85
Dietary calcium (mg)	738 (630 – 945)	786 (539 – 1 144)	671 (500 – 1 133)	742 (633 – 1 115)	0.81
Alcohol (drinks)	0.17 (0 – 0.87)	0.20 (0 – 1.13)	0.07 (0 – 0.37)	0.07 (0 – 0.60)	0.38
Use of dietary supplements‡ (%)
Vitamin D	11.9	9.8	6.5	22.3	0.29
Calcium	36.6	25.6	42.9	48.3	0.21
Family history of kidney cancer† (%)	0	0	2.6	2.9	0.42
Family history of any other cancer‡ (%)	60.0	51.0	64.1	79.4	0.07

^*Chi square test or Fisher’s exact test (when cells have expected counts <5) for categorical variables and Wilcoxon test for continuous variables

^†Assessed at baseline in 1982

^‡Assessed at the time closest to blood collection