Table 3.

Structural equation model for the mediated effect of arsenic exposure on birth gestational age through variation of the top-ten CpGs captured in the main principal component (PC₁) in the discovery phase.

Pathway	Effect	β Coefficient (95% CIs)	P value
log2 (As Water) → PC1	Direct	0.69 (0.50, 0.87)	<0.001
PC1→ Birth gestational age	Direct	−0.42 (−0.59, −0.25)	<0.001
Sex→ Birth gestational age	Direct	−0.05 (−1.17, 1.07)	0.93
log2 (As Water)→ Birth gestational age	Direct	0.06 (−0.18, 0.30)	0.62
log2 (As Water)→ PC1→ Birth gestational age	Indirect	−0.29 (−0.42, −0.15)	<0.001