Table 2.
Direct and indirect effects of E-DII on markers of T2D risk with body composition as mediators in black South African (SA) women.
| Variables | Total Effect (c) | Direct Effect (c’) | Indirect Effect (αβ) | Proportion of Mediation | |||
|---|---|---|---|---|---|---|---|
| Mediators and Outcomes | Estimate (95%CI) | p-Value | Estimate (95%CI) | p-value | 95%CI | p-value | % |
| Fasting glucose (mmol/L) | 0.17 (0.01–0.34) | 0.04 | |||||
| via waist circumference (cm) | 0.12 (−0.07–0.32) | 0.21 | 0.04 (−0.03–0.12) | 0.25 | 23.5 | ||
| via BMI (kg/m2) | 0.13 (−0.05–0.32) | 0.16 | 0.04 (−0.03–0.10) | 0.28 | 23.5 | ||
| via VAT (cm2) | 0.07 (−0.10–0.24) | 0.42 | 0.10 (0.00–0.20) | 0.04 | 58.8 | ||
| via body fat mass (kg) | 0.14 (−0.05–0.33) | 0.14 | 0.03 (−0.03–0.08) | 0.371 | 17.6 | ||
| Fasting insulin (mUI/mL) | 1.70 (0.45–2.96) | 0.008 | |||||
| via waist circumference (cm) | 0.38 (−0.87–1.63) | 0.55 | 1.32 (0.40–2.25) | 0.005 | 77.6 | ||
| via BMI (kg/m2) | 0.71 (−0.51–1.93) | 0.26 | 0.99 (0.20–1.78) | 0.01 | 58.2 | ||
| via VAT (cm2) | 0.08 (−1.19–1.35) | 0.90 | 1.62 (0.60–2.64) | 0.002 | 95.3 | ||
| via body fat mass (kg) | 0.89 (−0.30–2.09) | 0.14 | 0.81 (0.11–1.51) | 0.02 | 47.6 | ||
| HbA1c (%) | 0.10 (0.01–0.18) | 0.02 | |||||
| via waist circumference (cm) | 0.07 (−0.02–0.15) | 0.14 | 0.03 (−0.00–0.06) | 0.07 | 30.0 | ||
| via BMI (kg/m2) | 0.08 (−0.01–0.16) | 0.08 | 0.02 (−0.01–0.05) | 0.13 | 20.0 | ||
| via VAT (cm2) | 0.05 (−0.02–0.14) | 0.18 | 0.04 (0.00–0.08) | 0.04 | 40.0 | ||
| via body fat mass (kg) | 0.08 (−0.00–0.17) | 0.06 | 0.01 (−0.01–0.04) | 0.19 | 10.0 | ||
| HOMA2-IR | 0.25 (0.07–0.44) | 0.008 | |||||
| via waist circumference (cm) | 0.05 (−0.15–0.26) | 0.59 | 0.20 (0.05–0.35) | 0.009 | 80.0 | ||
| via BMI (kg/m2) | 0.10 (−0.09–0.30) | 0.30 | 0.15 (0.02–0.28) | 0.02 | 60.0 | ||
| via VAT (cm2) | 0.00 (−0.20–0.21) | 0.97 | 0.25 (0.08–0.41) | 0.003 | 100.0 | ||
| via body fat mass (kg) | 0.13 (−0.05–0.32) | 0.16 | 0.12 (0.01–0.23) | 0.03 | 48.0 | ||
| Two-hour glucose (mmol/L) | 0.48 (0.10–0.86) | 0.01 | |||||
| via waist circumference (cm) | 0.34 (−0.08–0.76) | 0.11 | 0.14 (−0.01–0.028) | 0.06 | 29.2 | ||
| via BMI (kg/m2) | 0.39 (−0.02–0.81) | 0.06 | 0.09 (−0.04–0.21) | 0.17 | 18.8 | ||
| via VAT (cm2) | 0.21 (−0.15–0.56) | 0.26 | 0.27 (0.08–0.47) | 0.006 | 56.3 | ||
| via body fat mass (kg) | 0.42 (0.00–0.83) | 0.05 | 0.06 (−0.04–0.17) | 0.27 | 12.5 | ||
| Matsuda Index * | 0.05 (0.02–0.09) | 0.003 | |||||
| via waist circumference (cm) | 0.01 (−0.04–0.06) | 0.62 | 0.04 (0.00–0.08) | 0.03 | 80.0 | ||
| via BMI (kg/m2) | 0.02 (−0.02–0.07) | 0.31 | 0.03 (−0.00–0.06) | 0.05 | 60.0 | ||
| via VAT (cm2) | −0.01 (−0.06–0.05) | 0.85 | 0.05 (0.01–0.10) | 0.01 | 100.0 | ||
| via body fat mass (kg) | 0.03 (−0.01–0.07) | 0.16 | 0.02 (−0.00–0.05) | 0.08 | 40.0 | ||
Regression coefficients c, α, β and c’ are shown in Figure 1a,b. All estimates were adjusted for the potential effects of age. BMI, body mass index; DII, dietary inflammatory index; HbA1c, glycated hemoglobin; HOMA2-IR, Homeostasis Model Assessment- insulin resistance; VAT, visceral adipose tissue. * Matsuda index was modelled as an inverse variable in order to calculate the proportion of mediation effect, thus the regression coefficients are positive instead of negative.