TABLE 3.
Overall and sub-group meta-analysis of the associations between salivary cortisol concentration and adiposity-related outcomes among children based on 11 included studies.
| Heterogeneity |
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| Sample | Adiposity outcomes | N of studies | Effect size (β, 95% CI) | P value | I2 (%) | χ2 | P-value | Tau-squared | P-value (Egger’s test)c |
| 1. Total daily output of salivary cortisol (lnAUCi or logAUCi, cross-sectional studies) | |||||||||
| (1) Salivary cortisol (lnAUCi; β, 95% CI)a | BMI z-score | 3 | 0.52 (−0.45, 1.49) | 0.29 | 70.0 | 6.66 | 0.04 | 0.48 | 0.655 |
| Measurement method | |||||||||
| LC-MS/MSb | BMI z-score | 1 | 0.05 (−1.74, 1.84) | 0.96 | – | – | – | – | |
| ELISA | BMI z-score | 2 | 0.66 (−0.62, 1.93) | 0.31 | 84.9 | 6.60 | 0.01 | 0.73 | |
| Country developmental context | |||||||||
| Developing countryb | BMI z-score | 1 | 0.05 (−1.74, 1.84) | 0.96 | – | – | – | – | |
| Developed country | BMI z-score | 2 | 0.66 (−0.62, 1.93) | 0.31 | 84.9 | 6.60 | 0.01 | 0.73 | |
| (2) Salivary cortisol (logAUCi; r, 95% CI) | BMI | 4 | 0.25 (0.04, 0.46) | 0.02 | 79.5 | 14.6 | 0.002 | 0.03 | 0.147 |
| Measurement method | |||||||||
| ELISA | BMI | 3 | 0.33 (0.09, 0.58) | <0.001 | 65.6 | 5.82 | 0.06 | 0.03 | |
| TRFIAb | BMI | 1 | 0.07 (0.01, 0.14) | 0.03 | – | – | – | – | |
| Sex | |||||||||
| Boysb | BMI | 1 | 0.30 (0.03, 0.57) | 0.03 | – | – | – | – | |
| Girls | BMI | 2 | 0.31 (−0.19, 0.80) | 0.002 | 92.0 | 12.49 | <0.001 | 0.12 | |
| Country developmental context | |||||||||
| Developed countries | BMI | 3 | 0.30 (0.02,0.61) | <0.001 | 86.2 | 14.47 | 0.001 | 0.06 | |
| Developing countriesb | BMI | 1 | 0.15 (−0.06, 0.37) | <0.001 | – | – | – | – | |
| Age group | BMI | ||||||||
| ≤12 years | BMI | 3 | 0.30 (0.02, 0.61) | <0.001 | 86.2 | 14.47 | 0.001 | 0.07 | |
| >12 years | BMI | 1 | 0.15 (−0.06, 0.37) | 0.17 | – | – | – | – | |
| (3) Morning salivary cortisol (r, 95% CI, cross-sectional studies) | BMI/BMI z-score | 2 | 0.15 (−0.17, 0.47) | 0.367 | 72.2 | 3.59 | 0.06 | 0.04 | – |
| (4) Morning salivary cortisol (β, 95% CI, cohort studies | BMI | 2 | −0.66 (−1.79, 0.47) | 0.25 | 82.9 | 5.86 | 0.02 | 0.57 | – |
BMI, body mass index; AUCi, saliva cortisol area-under-the-curve-increase; LC-MS/MS, liquid chromatography tandem mass spectrometry; ELISA, enzyme-linked immunosorbent assay; TRFIA, a time-resolved fluorescence immunoassay.
aAge of the children in the three studies were ≤12 years, and they did not report the association between salivary cortisol concentration and BMI/BMI z-score for boys or girls. Thus, we did not do the subgroups analysis across gender and age groups.
bIn the sub-group meta-analysis, only one study was included, so the data reported in the original study was presented.
cThe Egger’s tests was used to indicate the existence of publication bias. If p-value < 0, it was indicated that publication bias was existed, otherwise, no publication bias existed. Numbers in bold indicate significance.