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. Author manuscript; available in PMC: 2018 Oct 1.
Published in final edited form as: Environ Int. 2017 Jul 25;107:205–215. doi: 10.1016/j.envint.2017.07.016

Table 5. SEM estimates for the associations with GDM diagnosis or birth size measures per doubling of environmental pollutant exposures (latent constructsa), and direct and indirect effects from mediation analyses.

Outcome / Exposure Total Effectb Direct Effectb Indirect Effectb
Estimate (95% CI)c P Estimate (95% CI) c P Estimate (95% CI)c P

GDM (no/yes)
 OCs 0.45 (0.05, 0.86) 0.03 na na na na
 PFASs -0.25 (-1.06, 0.56) 0.72 na na na na
 Mercury -0.10 (-0.32, 0.11) 0.34 na na na na
Smoking (yes vs no)d -0.01 (-1.07, 1.05) 0.65 na na na na
Weight (g)
 OCs 16 (-27, 58) 0.48 15 (-27, 57) 0.48 0.7 (-4, 5) 0.77
 PFASs -169 (-359, 21) 0.11 -177 (-375, 21) 0.09 8 (-22, 38) 0.48
 Mercury 19 (-26, 64) 0.82 22 (-23, 66) 0.31 -2 (-8, 4) 0.48
Smoking (yes vs no)d -144 (-226, -62) 0.001 na na na na
Length (cm)
 OCs 0.05 (-0.13, 0.23) 0.57 0.06 (-0.12, 0.24) 0.55 0.00 (-0.01, 0.01) 0.75
 PFASs -0.06 (-0.96, 0.84) 0.91 -0.05 (-0.97, 0.86) 0.93 -0.01 (-0.05, 0.04) 0.54
 Mercury 0.02 (-0.18, 0.23) 0.83 0.02 (-0.19, 0.22) 0.88 0.01 (-0.01, 0.02) 0.31
Smoking (yes vs no)d -0.58 (-0.95, -0.20) 0.003 na na na na
Head circumference (cm)
 OCs 0.13 (0.01, 0.25) 0.02 0.13 (0.01, 0.25) 0.03 0.00 (-0.01, 0.01) 0.74
 PFAS -0.25 (-0.87, 0.37) 0.43 -0.24 (-0.86, 0.37) 0.44 -0.01 (-0.03, 0.02) 0.63
 Mercury 0.05 (-0.07, 0.17) 0.40 0.05 (-0.07, 0.17) 0.44 0.00 (-0.01, 0.01) 0.41
Smoking (yes vs no)d -0.21 (-0.43, 0.03) 0.09 na na na na
a

The latent construct of OC exposures is estimated based on measured maternal serum concentrations of ΣPCB, DDE and DDT. The latent construct of PFAS exposures is estimated based on measured maternal serum concentrations of PFOS, PFOA, PFHxS, PFDA and PFNA. The latent construct of mercury exposures is estimated based on measured mercury concentrations in maternal hair and cord blood.

b

The total effect reflects the estimated association between exposure and outcome unadjusted for any mediator. The direct effect reflects the estimated association adjusted for GDM as a mediator. The indirect effect approximates the difference between the total and direct effects.

c

All estimates are adjusted simultaneously for the three latent constructs of environmental pollutant exposures, and maternal age at delivery, education, parity, pre-pregnancy BMI (continuous), smoking during pregnancy and child sex. Estimates for the associations with GDM reflect the change in GDM odds (probit) per doubling of environmental pollutant exposures OR in the group of mothers who smoked during pregnancy compared to the reference exposure category (i.e. non-smokers: mean estimate=0). Estimates for the associations with the birth size measures reflect the mean change of the birth size measure per doubling of environmental pollutant exposures OR in the group of newborns whose mothers smoked during pregnancy compared to the reference exposure group (i.e. newborns of non-smokers: mean estimate=0). Estimates above 0 indicate positive associations, and estimates below 0 indicate inverse associations for all exposure-outcome associations shown in this table.

d

The estimates for smoking are extracted from the same outcome model as the latent constructs of environmental pollutant exposures and are shown for comparative purposes.

na: not applicable

SEM: structural equation model

GDM: gestational diabetes mellitus