Table 2. The odds ratios for breast cancer risk by plasma 25(OH)D concentration.

Plasma 25(OH)D	Cases		Controls		Crude model OR (95% CI)	Adjusted model* OR (95% CI)
Categorized (ng/ml)	No.	%	No.	%
Q1 (≤10.4)	325	54.8	145	25.0	1.00 (Reference)	1.00 (Reference)
Q2 (10.4–13.4)	148	25.0	145	25.0	0.44 (0.32–0.60)	0.43 (0.31–0.60)
Q3 (13.4–17.9)	81	13.6	145	25.0	0.28 (0.19–0.39)	0.24 (0.17–0.35)
Q4 (>17.9)	39	6.6	145	25.0	0.11 (0.07–0.17)	0.10 (0.06–0.15)
p-trend					<0.001	<0.001
Continuous
per 1 ng/ml increment	593		580		0.85 (0.82–0.88)	0.84 (0.81–0.87)

^*The OR was adjusted by age, age at first birth, age at menarche, use of contraceptive, menopausal status, first-degree relatives’ history of breast cancer and season of blood collection.