Serum vitamin D levels and survival of patients with colorectal cancer: Post-hoc analysis of a prospective cohort study

Table 1 Patient characteristics according to quartile of serum 25OHD (n = 257)

	Quartile 1 (3-7 ng/mL) n = 71	Quartile 2 (8-10 ng/mL) n = 58	Quartile 3 (11-15 ng/mL) n = 65	Quartile 4 (16-36 ng/mL) n = 63	P value
Serum 25OHD, ng/mL, mean ± SD	5.2 ± 1.7	9.0 ± 0.8	12.6 ± 1.4	21.9 ± 5.2
Age at surgery, years	64 ± 15	66 ± 13	65 ± 12	65 ± 10	0.76*¹
Gender, % female	41	43	34	26	0.18*²
Stage, %					0.78*²
Stage I	21	17	18	24
Stage II	23	31	37	22
Stage III	35	32	31	35
Stage IV	21	20	14	19
Location of tumor,%					0.24*²
Proximal colon	38	44	40	27
Distal colon	32	19	18	23
Rectum	30	37	42	50
Type of resection, %					0.84*²
R0	76	79	82	81
R1	9	10	8	4
R2	15	11	10	15
Number of lymph nodes with metastasis	2.2 ± 4.0	3.0 ± 6.8	2.2 ± 4.0	1.6 ± 3.0	0.87*³
Time period of surgery					< 0.001*²
May 2003 - December 2005	27	43	55	65
January 2006 - January 2008	73	57	45	35

*1: P value was calculated using one-way analysis of variance.
*2: P value was calculated using chi-square test.
*3: P value was calculated using Kruskal-Wallis rank test.
R0, no residual tumor; R1, microscopic residual tumor; R2, macroscopic residual tumor.

ISSN: 1471-2407