Table 7.
Mediation analysis among males.
| Skinfold thickness (mm) | B MI for age z–s core | Waist circumference (cm) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Exposure | Total effect | Direct effect | Indirect effect (Sobel p–value) | Total effect | Direct effect | Indirect effect (Sobel p–value) | Total effect | Direct effect | Indirect effect (Sobel p–value) |
| HSD11B2 CpG #1 AS MEDIATOR | |||||||||
| MEHP | |||||||||
| T1 | 2.67 (−0.37, 5.71)* | 3.12 (−0.09, 6.33)* | −0.48 (0.27) | 0.28 (0.002, 0.57)** | 0.31 (0.01, 0.60)** | −0.02 (0.40) | 1.86 (−0.61, 4.33) | 2.25 (−0.3, 4.8)* | −0.39 (0.26) |
| T2 | 0.63 (−2.42, 3.67) | 0.9 (−2.13, 3.93) | −0.24 (0.55) | 0.23 (−0.08, 0.55) | 0.25 (−0.06, 0.56) | −0.01 (0.58) | 1.41 (−0.91, 3.74) | 1.61 (−0.67, 3.9) | −0.19 (0.55) |
| T3 | −0.63 (−3.63, 2.37) | 0.3 (−2.34, 2.94) | −0.89 (0.11) | 0.09 (−0.18, 0.37) | 0.18 (−0.08, 0.43) | −0.06 (0.21) | −0.34 (−2.57, 1.89) | 0.37 (−1.67, 2.41) | −0.68 (0.12) |
| PA visit 1 | −1.90 (−3.91, 0.11)* | −1.87 (−3.76, 0.02)* | −0.24 (0.37) | −0.15 (−0.36, 0.05) | −0.16 (−0.36, 0.04) | −0.01 (0.68) | −1.33 (−2.9, 0.24) | −1.31 (−2.86, 0.23) | −0.11 (0.47) |
| MBzP | |||||||||
| T1 | 1.91 (−0.3, 4.12)* | 1.71 (−0.41, 3.83) | 0.23 (0.37) | 0.19 (−0.001, 0.39)* | 0.18 (−0.01, 0.38)* | 0.01 (0.59) | 1.55 (−0.13, 3.22)* | 1.38 (−0.22, 2.99)* | 0.19 (0.36) |
| T2 | 2.00 (−0.43, 4.43) | 2.06 (−0.24, 4.37)* | 0.07 (0.83) | 0.25 (0.01, 0.49)** | 0.26 (0.02, 0.50)** | 0.00 (0.83) | 2.11 (0.27, 3.95)** | 2.13 (0.37, 3.88)** | 0.05 (0.83) |
| T3 | −0.49 (−2.93, 1.94) | −1.35 (−3.8, 1.1) | 0.84 (0.12) | −0.12 (−0.33, 0.09) | −0.17 (−0.40, 0.07) | 0.05 (0.25) | −0.35 (−2.24, 1.55) | −0.98 (−2.98, 1.02) | 0.63 (0.14) |
| PA visit 1 | −2.43 (−4.69, −0.17)** | −2.29 (−4.58, −0.01)* | −0.11 (0.73) | −0.17 (−0.41, 0.07) | −0.17 (−0.42, 0.08) | 0.00 (0.77) | −1.91 (−3.64, −0.19)** | −1.86 (−3.6, −0.11)** | −0.05 (0.73) |
| HSD11B2 CpG #2 AS MEDIATOR | |||||||||
| MEHP | |||||||||
| T1 | 2.67 (−0.37, 5.71)* | 3.02 (−0.1, 6.14)* | −0.37 (0.34) | 0.28 (0.002, 0.57)** | 0.32 (0.04, 0.6)** | −0.04 (0.33) | 1.86 (−0.61, 4.33) | 2.19 (−0.2, 4.59)* | −0.33 (0.33) |
| T2 | 0.63 (−2.42, 3.67) | 0.83 (−2.32, 3.98) | −0.17 (0.69) | 0.23 (−0.08, 0.55) | 0.26 (−0.06, 0.57) | −0.02 (0.69) | 1.41 (−0.91, 3.74) | 1.58 (−0.76, 3.91) | −0.15 (0.69) |
| T3 | −0.63 (−3.63, 2.37) | −0.51 (−3.4, 2.38) | −0.07 (0.80) | 0.09 (−0.18, 0.37) | 0.12 (−0.15, 0.39) | −0.01 (0.80) | −0.34 (−2.57, 1.89) | −0.25 (−2.42, 1.92) | −0.06 (0.80) |
| PA visit 1 | −1.90 (−3.91, 0.11)* | −1.52 (−3.34, 0.31) | −0.64 (0.26) | −0.15 (−0.36, 0.05) | −0.11 (−0.33, 0.1) | −0.06 (0.38) | −1.33 (−2.9, 0.24) | −1.01 (−2.59, 0.57) | −0.43 (0.34) |
| MBzP | |||||||||
| T1 | 1.91 (−0.30, 4.12)* | 2.09 (−0.16, 4.33)* | −0.16 (0.55) | 0.19 (−0.001, 0.39)* | 0.21 (0.01, 0.40)** | −0.02 (0.54) | 1.55 (−0.13, 3.22)* | 1.71 (0.06, 3.37)** | −0.15 (0.54) |
| T2 | 2.00 (−0.43, 4.43) | 1.95 (−0.38, 4.27) | 0.19 (0.54) | 0.25 (0.01, 0.49)** | 0.25 (0.01, 0.48)** | 0.02 (0.54) | 2.11 (0.27, 3.95)** | 2.02 (0.27, 3.76)** | 0.16 (0.53) |
| T3 | −0.49 (−2.93, 1.94) | −0.6 (−2.95, 1.74) | 0.08 (0.68) | −0.12 (−0.33, 0.09) | −0.12 (−0.32, 0.08) | 0.01 (0.68) | −0.35 (−2.24, 1.55) | −0.42 (−2.23, 1.39) | 0.07 (0.68) |
| PA visit 1 | −2.43 (−4.69, −0.17)** | −2.04 (−4.23, 0.15)* | −0.39 (0.25) | −0.17 (−0.41, 0.07) | −0.14 (−0.39, 0.11) | −0.03 (0.32) | −1.91 (−3.64, −0.19)** | −1.65 (−3.35, 0.04)* | −0.26 (0.30) |
Effect estimates (95% CI) are reported in the table.
p < 0.1,
p < 0.05.
Phthalate concentrations (μg/L) were natural log transformed. Total effects represent the effect estimate of the phthalate concentrations on measures of adiposity from a generalized estimating equation relating repeated measures of adiposity to phthalates leaving the potential mediator (DNA methylation at HSD11B2 CpG sites 1 or 2) out of the model and adjusting for specific gravity, maternal education, and age. Direct effects represent the effect estimate of phthalate concentration in the same model but with DNA methylation also included. The indirect effect is the product of the effect of the exposure on the mediator and the effect of the mediator on the outcome. The Sobel test was used to test significance of the mediation pathway.