Association of salivary C-reactive protein with the obesity measures and markers in children

Figures & data

Table 1 Anthropometric measurements of study subjects

Parameter	NW	OW/OB	p-value
Sex (N=76)	40	36	-
Male/Female (41/35)	20/20	21/15	-
Age (years)	8.38±0.23	8.49±0.23	p<0.73
Height (cm)	131.9±1.82	135.6±1.67	p<0.14
Weight (kg)	28.32±1.05	39.32±1.83***	p<0.0001
BMI (kg/m^2)	16.01±0.24	21.10±0.50***	p<0.0001
BMI z-score	−0.04±0.13	2.02±0.11***	p<0.0001
Waist Circumference (cm)	60.18±0.74	71.19±1.44***	p<0.0001
WC z-score	0.15±0.08	1.26±0.08***	p<0.0001
WHtR z-score	−0.13±0.10	1.02±0.08***	p<0.0001

Notes: ***p-values were compared to NW group. Data presented as mean±SEM.

Abbreviations: BMI, body mass index; WC, waist circumference; WHtR, waist-to-height ratio; NW, normal weight; OW/OB, overweight/obese; SEM, standard error.

Figure 1 Salivary concentration of obesity markers in comparison with normal weight (NW) and overweight/obese (OW/OB) participants. Magnetic Luminex performance multiplex assay shows the expression of (A) resistin (n=40 and 36), (B) CCL2/MCP-1 (n=40 and 36), (C) TNF-α (n=40 and 36), (D) IL-6 (n=40 and 31), (E) CRP (n=40 and 35), (F) IL-10 (n=40 and 33), and (G) complement Factor D/adipsin (n=40 and 36). Data are expressed with Box-Whisker plots with median, first (25th percentile) and third (75th) quartile range with minimum and maximum of the blot. ***p<0.0001 vs NW; **p<0.001 vs NW.

Abbreviation: NS, not significant.

Table 2 Area under the curve derived by ROC curve analysis

Parameter	AUC	SE	Cut-off	Sensitivity	1-Specificity	Significance	95% CI
							Lower	Upper
BMI z-score	0.992	0.007	1.11	0.97	0.03	0.0001	0.978	1.000
WC z-score	0.943	0.029	0.71	0.94	0.08	0.0001	0.886	1.000
WHtR z-score	0.943	0.026	0.48	0.90	0.13	0.0001	0.891	0.994
CRP	0.866	0.044	4.54	0.87	0.25	0.0001	0.780	0.952
Resistin	0.731	0.063	7.19	0.61	0.25	0.001	0.606	0.855
MCP-1	0.715	0.065	4.13	0.65	0.15	0.002	0.587	0.844
TNF-α	0.694	0.067	1.74	0.55	0.18	0.005	0.564	0.825
IL-6	0.673	0.066	2.70	0.61	0.33	0.01	0.544	0.801

Abbreviations: ROC, receiver operating curve; AUC, area under curve; BMI, body mass index; WC, waist circumference; WHtR, waist-to-height ratio; CRP, C-reactive protein; MCP-1, monocyte chemoattractant protein 1; TNF-α, tumor necrosis factor – α; IL-6, interleukin-6; SE, standard error; CI, confidence interval.

Figure 2 Receiver operating characteristic (ROC) curve analysis demonstrating the discriminative value of the participating children in anthropometric and obesity markers such as CRP, IL-6, CCL2/MCP-1, resistin, and TNF-α. Diagonal solid line represents the reference line.

Abbreviations: BMI, body mass index; WC, waist circumference; WHtR, waist-to-height ratio; CRP, C-reactive protein; MCP-1, monocyte chemoattractant protein 1; TNF-α, tumor necrosis factor – α; IL-6, interleukin-6.

Table 3 Pairwise Pearson Correlation between salivary obesity biomarkers and anthropometric parameters

	CRP		Resistin		MCP-1		TNF-α		IL-6		Complement factor D/adipsin		IL-10
	r	p	r	p	r	p	r	p	r	p	r	p	r	p
BMI z-score	0.573	<0.0001	0.450	<0.0001	0.441	<0.0001	0.188	<0.105	0.209	<0.080	−0.190	<0.100	−0.401	<0.0001
WC z-score	0.542	<0.0001	0.440	<0.0001	0.430	<0.0001	0.159	<0.171	0.168	<0.162	−0.154	<0.184	−0.436	<0.0001
WHtR z-score	0.525	<0.0001	0.421	<0.0001	0.389	<0.001	0.170	<0.142	0.141	<0.239	−0.160	<0.168	−0.406	<0.0001
CRP	1	-	0.547	<0.0001	0.448	<0.0001	0.679	<0.0001	0.738	<0.0001	0.010	<0.935	−0.406	<0.0001
Resistin	0.547	<0.0001	1	-	0.803	<0.0001	0.117	<0.312	0.221	<0.064	0.529	<0.0001	−0.802	<0.0001
MCP-1	0.448	<0.0001	0.803	<0.0001	1	-	−0.053	<0.651	0.146	<0.223	0.569	<0.0001	−0.876	<0.0001
TNF-α	0.679	<0.0001	0.117	<0.312	−0.053	<0.651	1	-	0.898	<0.0001	−0.197	<0.089	0.110	<0.353
IL-6	0.738	<0.0001	0.221	<0.064	0.146	<0.223	0.898	<0.0001	1	-	−0.073	<0.544	−0.084	<0.488
CFD/Adipsin	0.010	<0.935	0.529	<0.0001	0.569	<0.0001	−0.197	<0.089	−0.073	<0.544	1	-	−0.540	<0.0001
IL-10	−0.406	<0.0001	−0.802	<0.0001	−0.876	<0.0001	0.110	<0.353	−0.084	<0.488	−0.540	<0.0001	1	-

Abbreviations: r, Pearson Correlation; BMI, body mass index; WC, waist circumference; WHtR, waist-to-height ratio; CRP, C-reactive protein; MCP-1, monocyte chemoattractant protein 1; TNF-α, tumor necrosis factor – α; IL-6, interleukin-6; CFD, complement factor D; IL-10, interleukin-10.

Figure 3 Result of linear regression analysis and Pearson correlation analysis between natural log-transformed CRP data and BMI z-score, WC z-score and WHtR z-score. Scatter plot represented with the p-value of 0.0001 for Pearson correlation coefficients.

Abbreviations: BMI, body mass index; WC, waist circumference; WHtR, waist-to-height ratio; CRP, C-reactive protein.

Figure 4 Evaluation of the correlation of natural log-transformed CRP with other obesity biomarkers. Scatter plot shows the correlation coefficient values with of CRP with resistin, CCL2/MCP-1, TNF-α, IL-6, IL-10, and complement factor D/adipsin.

Abbreviation: CRP, C-reactive protein.