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. Author manuscript; available in PMC: 2021 Apr 1.
Published in final edited form as: Environ Int. 2020 Feb 29;137:105523. doi: 10.1016/j.envint.2020.105523

Table 3.

Risk Ratios (RR) and 95% Confidence Intervals (95% Cis) for preterm birth (<37 weeks) per natural log-unit increase in maternal preconception urinary phenol concentrations among 417 mothers in the Environment and Reproductive Health (EARTH) Study, 2005–2018.

Phenol
Biomarker		 Preterm Birth
Model 1
Unadjusteda 		Preterm Birth
Model 2
Covariatesb 		Preterm Birth
Model 3
Covariates + Prenatalc 		Preterm Birth
Model 4
Covariates + Paternal Precond
RR (95% CI) RR (95% CI) RR (95% CI) RR (95% CI)
Bisphenol A
1.95 (1.23, 3.09) 1.94 (1.20, 3.14) 2.20 (1.29, 3.75) 2.00 (1.00, 3.99)
p-values 0.005 0.007 0.004 0.05
Preterm Birth n/N 34/417 34/417 31/384 18/228
Bisphenol S
2.31 (1.04, 5.14) 2.42 (1.01, 5.77) 3.33 (1.13, 8.80) DNC
p-values 0.04 0.05 0.03
Preterm Birth n/N 9/163 9/163 7/145 2/74
∑Parabense
0.99 (0.76, 1.29) 0.99 (0.76, 1.30) 0.90 (0.63, 1.29) 1.00 (0.65, 1.54)
p-values 0.93 0.95 0.57 0.99
Preterm Birth n/N 33/405 33/405 30/372 17/221
Benzophenone-3
0.91 (0.70, 1.19) 0.91 (0.68, 1.22) 0.93 (0.63, 1.39) 1.55 (0.89, 2.70)
p-values 0.50 0.53 0.74 0.12
Preterm Birth n/N 21/278 21/278 18/254 8/137
Triclosan
0.77 (0.58, 1.02) 0.78 (0.59, 1.04) 0.78 (0.53, 1.14) 1.16 (0.68, 1.97)
p-values 0.07 0.10 0.19 0.59
Preterm Birth n/N 21/278 21/278 18/254 8/137

Note: n, number of preterm birth cases; N, sample size for maternal preconception biomarker concentrations; DNC, did not converge.

a

Models 1: Unadjusted.

b

Models 2: Adjusted for age (continuous), BMI (continuous), ART (yes/no), smoking (ever/never), education (categorical).

c

Models 3: Adjusted for age (continuous), BMI (continuous), ART (yes/no), smoking (ever/never), education (categorical) + prenatal biomarker exposure (continuous log-concentration).

d

Models 4: Adjusted for age (continuous), BMI (continuous), ART (yes/no), smoking (ever/never), education (categorical) + paternal preconception biomarker exposure (continuous log-concentration).

e

ΣParabens: the molar sum of parabens was estimated by dividing each concentration by its molecular weight and then summing: ∑Parabens = [(Methylparaben * (1/152.15)) + Propylparaben * (1/180.20)) + Butylparaben * (1/194.23))]. We then weighted this sum by the molecular weight of methylparaben (152.15) to convert the molar concentration to units of ng/ml.