Table 5. Direct and indirect effects of nut consumption on markers of insulin resistance and inflammation with BMI, WC, apVAT, VAI and LAP as mediators among US adults.
| Mediator and outcomes |
Direct effect (γ') | Indirect effect (α#β) | Proportion of mediation, % | ||
|---|---|---|---|---|---|
| Estimate | P | Estimate | Sobel test statistic | ||
| BMI | |||||
| Serum CRP (mg/dl) | −0.032* | <0.001 | −0.008* | <0.001 | 20.1% |
| Serum apolipoprotein B (mg/dL) | −0.005 | 0.977 | −0.024 | 0.352 | 81.1% |
| Fasting blood glucose (mg/dl) | −0.402* | <0.001 | −0.091* | <0.001 | 18.4% |
| Plasma Insulin (uU/mL) | −0.014* | <0.001 | −0.003* | <0.001 | 18.0% |
| HOMA-IR | −0.017* | <0.001 | −0.003 | 0.226 | 17.4% |
| HOMA-B | −0.006 | 0.198 | −0.002 | 0.123 | 22.4% |
| HbA1c (%) | −0.015* | <0.001 | −0.002* | <0.001 | 15.6% |
| 2 h Blood glucose (mg/dL) | −0.802* | <0.001 | −0.094 | 0.256 | 10.1% |
| TyG index | −0.007* | <0.001 | −0.003* | <0.001 | 29.6% |
| TG:HDL ratio | −0.027 | 0.235 | −0.014* | <0.001 | 29.3% |
| WC | |||||
| Serum CRP (mg/dl) | −0.035* | <0.001 | −0.008* | <0.001 | 21.6% |
| Serum apolipoprotein B (mg/dL) | −0.025 | 0.925 | −0.352 | 0.625 | 65.2% |
| Fasting blood glucose (mg/dL) | −0.395* | <0.001 | −0.100* | <0.001 | 20.6% |
| Plasma Insulin (uU/mL) | −0.014* | <0.001 | −0.004 | 0.352 | 21.6% |
| HOMA-IR | −0.017* | <0.001 | −0.004 | 0.296 | 21.2% |
| HOMA-B | −0.006 | 0.263 | −0.003 | 0.635 | 20.3% |
| HbA1c (%) | −0.015* | <0.001 | −0.003* | <0.001 | 16.5% |
| 2 h Blood glucose (mg/dL) | −0.832* | <0.001 | −0.128 | 0.133 | 13.4% |
| TyG index | −0.006* | <0.001 | −0.003* | <0.001 | 21.6% |
| TG:HDL ratio | −0.253 | 0.133 | −0.010* | <0.001 | 39.5% |
| apVAI | |||||
| Serum CRP (mg/dL) | −0.231* | <0.001 | −0.003 | 0.132 | 13.6% |
| Serum apolipoprotein B (mg/dL) | 0.562 | 0.102 | −0.103 | 0.826 | 12.0% |
| Fasting blood glucose (mg/dL) | −0.352 | 0.235 | −0.032 | 0.621 | 10.1% |
| Plasma Insulin (uU/mL) | −0.014 | 0.235 | −0.001 | 0.362 | 1.25% |
| HOMA-IR | −0.018* | <0.001 | −0.001 | 0.425 | 10.3% |
| HOMA-B | −0.001 | 0.523 | −0.0006 | 0.426 | 35.6% |
| HbA1c (%) | −0.006 | 0.426 | 0.001 | 0.235 | 21.1% |
| 2 h Blood glucose (mg/dL) | −0.900 | 0.125 | −0.138 | 0.425 | 13.3% |
| TyG index | −0.003 | 0.142 | −0.001 | 0.429 | 9.2% |
| TG:HDL ratio | −0.038 | 0.415 | −0.006 | 0.352 | 14.3% |
| VAI | |||||
| Serum CRP (mg/dL) | −0.035* | <0.001 | −0.005* | <0.001 | 14.5% |
| Serum apolipoprotein B (mg/dL) | 0.273 | 0.412 | −0.235 | 0.415 | 12.6% |
| Fasting blood glucose (mg/dL) | −0.384* | <0.001 | −0.133* | <0.001 | 24.1% |
| Plasma Insulin (uU/mL) | −0.0102* | <0.001 | −0.008* | <0.001 | 46.5% |
| HOMA-IR | −0.012* | <0.001 | −0.010* | <0.001 | 43.6% |
| HOMA-B | −0.004 | 0.235 | −0.005* | <0.001 | 56.2% |
| HbA1c (%) | −0.015* | <0.001 | −0.003* | <0.001 | 17.2% |
| 2 h Blood glucose (mg/dL) | −0.532 | 0.415 | −0.462* | <0.001 | 44.3% |
| TyG index | 0.001 | 0.362 | −0.011* | <0.001 | 13.2% |
| TG:HDL ratio | 0.026 | 0.096 | −0.061* | <0.001 | 75.2% |
| LAP | |||||
| Serum CRP (mg/dL) | −0.034* | <0.001 | −0.006* | <0.001 | 17.1% |
| Serum apolipoprotein B (mg/dL) | 0.161 | 0.235 | −0.221* | <0.001 | 7.6% |
| Fasting blood glucose (mg/dL) | −0.402* | <0.001 | −0.090* | <0.001 | 21.3% |
| Plasma Insulin (uU/mL) | −0.010* | <0.001 | −0.007* | <0.001 | 37.2% |
| HOMA-IR | −0.014* | <0.001 | −0.008* | <0.001 | 36.6% |
| HOMA-B | −0.004 | 0.352 | −0.003* | <0.001 | 21.2% |
| HbA1c (%) | −0.015* | <0.001 | −0.002* | <0.001 | 14.4% |
| 2 h Blood glucose (mg/dL) | −0.632 | 0.241 | −0.365* | <0.001 | 34.2% |
| TyG index | −0.002 | 0.425 | −0.007 | 0.241 | 76.2% |
| TG:HDL ratio | 0.004 | 0.965 | −0.035* | <0.001 | 10.2% |
Abbreviations: BMI: body mass index, WC: waist circumference, apVAT: anthropometrically-predicted visceral adipose tissue, HOMA-IR: Homeostatic model assessment of insulin resistance; HOMA-B: Homeostatic model assessment of β-cell function, HbA1c: glycated haemoglobin A1c, TyG index: triglyceride-glucose index, HDL: high-density lipoprotein, CRP: C-reactive protein.
All estimates were adjusted for age, sex, race/ethnicity, educational, smoking and level of physical activity. Regression coefficients α, β, γ and γ’ are shown in Supplementary Figure 1.