Circulating levels of 25-hydroxyvitamin D and risk of breast cancer: a nested case-control study

Breast Cancer Research

Table 4 Odds ratios and 95% confidence intervals for breast cancer risk according to pre-specified categories of circulating 25(OH)D concentration by season^a

		Pre-specified categories, nmol/L				Continuous^b	Pvalue
		< 50	50-74	75+	P _trend
Winter (Jan., Feb., March, April)
Both cohorts^c	Cases/controls	391/704	244/472	65/116
	OR (95% CI)	1.0 (ref)	0.94 (0.77, 1.15)	1.06 (0.76, 1.48)	0.95	0.97 (0.82, 1.15)	0.74
NYUWHS	Cases/controls	193/331	105/217	35/65
	OR (95% CI)	1.0 (ref)	0.82 (0.61, 1.10)	0.91 (0.58, 1.44)	0.35	0.90 (0.73, 1.13)	0.37
NSMSC	Cases/controls	198/373	139/255	30/51
	OR (95% CI)	1.0 (ref)	1.10 (0.83, 1.46)	1.25 (0.76, 2.06)	0.34	1.11 (0.85, 1.47)	0.44
Summer (July, Aug., Sept.)
Both cohorts^c	Cases/controls	113/186	217/348	99/212
	OR (95% CI)	1.0 (ref)	1.02 (0.75, 1.38)	0.76 (0.53, 1.09)	0.14	0.82 (0.64, 1.05)	0.12
NYUWHS	Cases/controls	77/121	125/190	67/148
	OR (95% CI)	1.0 (ref)	1.07 (0.73, 1.56)	0.69 (0.45, 1.07)	0.10	0.80 (0.60, 1.07)	0.14
NSMSC	Cases/controls	36/65	92/158	32/64
	R (95% CI)	1.0 (ref)	0.99 (0.59, 1.67)	0.89 (0.46, 1.70)	0.72	0.88 (0.52, 1.47)	0.61

^aAdjusted for age at menarche (continuous), family history of breast cancer (no or yes), age at first birth/parity (≤ 20, 21-25, 26-30, > 30 years, nulliparous), body mass index (continuous), hormone replacement therapy use (never or ever), and alcohol consumption (continuous). ^bOdds ratio (OR) for a doubling in 25(OH)D level. ^cAdjusted for cohort in addition to all factors in footnote a. 25(OH)D, 25-hydroxyvitamin D; CI, confidence interval; NSMSC, Northern Sweden Mammary Screening Cohort; NYUWHS, New York University Women's Health Study; ref, reference.

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