Serum 25-hydroxyvitamin D and postmenopausal breast cancer survival: a prospective patient cohort study

Breast Cancer Research

Table 5 Multivariate-adjusted^a stratified analyses of overall mortality according to tertiles of serum 25(OH)D

		Serum 25(OH)D
		Continuous			Categorical
		per 10 nmol/L decrement			< 35 nmol/L		35-55 nmol/L		≥ 55 nmol/L
Variable	Total no.	HR	95%CI	P _trend ^b	HR	95%CI	HR	95%CI		P _interaction ^c
BMI, kg/m^2d										0.74
< 26	382	1.05	0.66 to 1.44	0.81	0.64	0.08 to 5.00	0.02	0.00 to 2.06	Referent
≥ 26	393	1.15	0.94 to 1.36	0.20	2.57	0.88 to 7.54	0.60	0.19 to 1.92	Referent
Leisure time physical activity, MET-h/wk										0.49
< 37	631	1.04	0.92 to 1.17	0.50	1.19	0.62 to 2.29	0.63	0.30 to 1.32	Referent
≥ 37	629	1.19	1.03 to 1.35	0.03	1.90	0.85 to 4.24	0.57	0.22 to 1.48	Referent
HRT use										0.40
Never, past	746	1.13	1.01 to 1.25	0.04	1.89	1.09 to 3.26	0.61	0.31 to 1.19	Referent
Current	506	1.03	0.86 to 1.21	0.73	0.89	0.26 to 3.05	1.17	0.46 to 2.98	Referent
ER status										0.78
ER⁺	903	1.08	0.97 to 1.19	0.17	1.70	0.95 to 3.05	0.72	0.39 to 1.35	Referent
ER^-	276	1.09	0.84 to 1.35	0.50	1.48	0.38 to 5.76	0.81	0.21 to 3.09	Referent

25(OH)D, 25-hydroxyvitamin D; BMI, body mass index; CI, confidence interval; ER, estrogen receptor; HR, hazard ratio; HRT, hormone replacement therapy.
^a Stratified by age at diagnosis and season, adjusted for tumor size, nodal status, metastases, tumor grade, estrogen/progesterone receptor status, diabetes, mode of detection.
^b Calculated by using serum 25(OH)D as a continuous variable.
^c Calculated by entering in the model the cross-product of 25(OH)D as a continuous variable with the covariate as a binary variable. Cutpoints for BMI and leisure time physical activity were based on median values.
^d Participants with blood collection after start of chemotherapy and with BMI obtained more than one month before/after blood collection were excluded from this analysis stratified by BMI.

ISSN: 1465-542X