Table 2.

Associations between urinary metal concentrations and Z-scores for birth weight in the prenatal cohort (discovery set) and the Healthy Baby Cohort (replication set).

	β in the optimal elastic net model in the prenatal cohort a	Association between metals and birth weight in the Healthy Baby Cohort b
		β (95% CI)	P
V	−0.011	−0.035 (−0.059, −0.010)	0.006∗
Mn	−0.007	−0.020 (−0.045, 0.005)	0.12
Fe	−0.082	−0.013 (−0.040, 0.014)	0.35
Co	0.034	0.073 (0.049, 0.097)	<0.001∗
Zn	0.072	0.040 (0.016, 0.065)	0.001∗
Sr	0.089	0.028 (0.005, 0.052)	0.02
Cs	−0.046	−0.015 (−0.034, 0.004)	0.12
Ba	−0.031	−0.007 (−0.030, 0.016)	0.55

β, regression coefficient; CI, confidence interval; FDR, false discovery rate.

∗ P-values remained significant after Bonferroni correction (P < 0.00625; 0.05/8 metals).

^aOnly metals with non-zero regression coefficients in the optimal elastic net model were shown.

^bAs a validation, associations between each metal and Z-scores for birth weight were estimated using linear regression models. All pairwise interactions were estimated jointly in the validation set using a single linear regression model.