. Author manuscript; available in PMC: 2015 Mar 25.

Published in final edited form as: Am J Perinatol. 2011 Apr 15;28(9):667–672. doi: 10.1055/s-0031-1276731

Table 2.

Unadjusted and Adjusted ORs for Preterm Birth According to Vitamin D Status

Serum 25(OH)D Level (nmol/L)	Controls (n)	Preterm Birth (n)	Unadjusted OR (95% CI)	p Value	Adjusted OR (95% CI)^*	p Value
≥ 75	88	29	1.00 (Reference group)	–	1.00 (Reference group)	–
50–74.9	24	8	1.01 (0.42–2.46)	0.61	0.87 (0.34–2.25)	0.77
<50	8	3	1.14 (0.31–4.26)	0.99	0.82 (0.19–3.57)	0.79

Adjusted for maternal age (continuous), insurance status (dichotomous), body mass index (continuous), gestational age at serum collection (continuous), and season of blood draw (winter, spring, summer, fall).

25(OH)D, 25-hydoxyvitamin D; CI, confidence interval; OR, odds ratio.