Table 3.

Adjusted¹ odds ratio (95% Confidence Interval) of overall, spontaneous, and placental preterm birth (PTB) in association with an interquartile range difference in urinary trace metal concentration and by principal components (PC).

	Overall PTB	Spontaneous PTB	Placental PTB
Metal	(n cases = 99) (n controls = 291)	(n cases = 46) (n controls = 291)	(n cases = 22) (n controls = 291)
As	0.98 (0.72, 1.33)	0.89 (0.58, 1.38)	1.07 (0.49, 2.35)
Ba	1.27 (0.90, 1.77)	1.27 (0.84, 1.93)	1.51 (0.75, 3.04)
Cd	1.03 (0.78, 1.37)	1.13 (0.79, 1.63)	1.73 (0.64, 4.66)
Cu	1.41 (1.12, 1.78)	1.52 (1.14, 2.03)	1.50 (0.99, 2.27)
Hg	1.13 (0.85, 1.51)	1.28 (0.82, 1.98)	1.02 (0.70, 1.50)
Mn	1.08 (0.85, 1.37)	1.14 (0.77, 1.69)	0.97 (0.58, 1.61)
Mo	1.05 (0.80, 1.37)	1.14 (0.71, 1.82)	0.97 (0.60, 1.58)
Ni	0.96 (0.75, 1.22)	1.19 (0.77, 1.85)	0.99 (0.71, 1.39)
Pb	1.19 (0.91, 1.55)	1.15 (0.82, 1.60)	1.45 (0.91, 2.31)
Se	1.33 (0.98, 1.81)	1.69 (1.11, 2.57)	0.83 (0.53, 1.29)
Sn	0.89 (0.65, 1.22)	0.99 (0.68, 1.43)	0.83 (0.53, 1.29)
Tl	0.96 (0.79, 1.16)	0.95 (0.64, 1.41)	0.96 (0.66, 1.42)
Zn	1.15 (0.85, 1.57)	1.21 (0.78, 1.90)	1.04 (0.50, 2.14)
Be	0.48 (0.18, 1.29)	0.37 (0.09, 1.64)	0.93 (0.17, 4.98)
Cr	1.83 (0.93, 3.61)	1.39 (0.57, 3.37)	4.19 (1.16, 15.1)
U	1.61 (0.79, 3.27)	2.05 (0.88, 4.80)	1.58 (0.36, 6.87)
W	1.33 (0.73, 2.42)	1.94 (0.95, 3.97)	0.71 (0.16, 3.09)
Principal Components
Toxic	1.03 (0.79, 1.34)	1.02 (0.72, 1.44)	1.37 (0.80, 2.33)
Essential	1.36 (1.05, 1.76)	1.58 (1.14, 2.20)	1.16 (0.64, 2.10)
Fish-related	1.05 (0.83, 1.35)	1.09 (0.79, 1.51)	0.93 (0.59, 1.46)

¹Adjusted for specific gravity, maternal age, race, education, pre-pregnancy BMI, gestational age at time of sample collection. Shading denotes metals with >70% of samples below the limit of detection modeled as detect vs. non-detect.