Association of Serum Amylase Activity and the Copy Number Variation of AMY1/2A/2B with Metabolic Syndrome in Chinese Adults

Figures & data

Table 1 Clinical Characteristics of the Study Participants

Factors	GROUP		χ^2/t	p
	Healthy	Patient
	N=300	N=260
Sex (M/F)	207/93	164/96	2.185	0.139*
Age (y)	37.72±16.01	52.35±12.39	−11.954	<0.001
BMI (kg/m2)	22.81±2.62	25.61±4.15	−6.962	<0.001
SBP (mmHg)	118.65±13.88	136.31±17.52	−10.792	<0.001
DBP (mmHg)	70.78±10.13	82.96±12.40	−10.429	<0.001
FPG (mmol/L)	4.81±0.44	10.21±3.71	−23.307	<0.001
TG (mmol/L)	0.84(0.66~1.13)	2.21(1.56~3.29)	−17.682	<0.001^#
TC (mmol/L)	3.94±0.53	5.59±1.22	−20.321	<0.001
HDL-C (mmol/L)	1.46±0.25	1.13±0.37	12.089	<0.001
LDL-C (mmol/L)	2.36±0.45	3.67±1.03	−18.949	<0.001
T-AMY (U/L)	71.30±20.78	52.98±18.06	11.166	<0.001
P-AMY (U/L)	30.34±8.25	24.32±9.05	8.236	<0.001
S-AMY (U/L)	40.87±17.60	28.62±14.05	9.155	<0.001
	N=189	N=122
AMY1 CN (copies)	7.11±2.19	6.72±2.21	1.503	0.133
AMY2A CN (copies)	2.10±0.70	2.09±0.62	0.133	0.894
AMY2B CN (copies)	1.92±0.49	1.91±0.55	0.181	0.857

Notes: Data are expressed as mean ± SD. TG data expressed as median and range. p-values were determined using t-test, *using Chi-squared test, ^#using Mann–Whitney U-test.

Abbreviations: BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FPG, fasting plasma glucose; TG, triglyceride; TC, total cholesterol; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; T-AMY, total amylase; P-AMY, pancreatic amylase; S-AMY, salivary amylase; AMY1, salivary amylase gene; AMY2A/ AMY2B, pancreatic amylase gene; CN, copy number.

Table 2 Correlation Coefficients Between the Study Parameters

	T-AMY (U/L)	P-AMY (U/L)	S-AMY (U/L)	AMY1 CN (Copies)	AMY2A CN (Copies)	AMY2B CN (Copies)
Age (y)	−0.070	−0.052	−0.060	−0.002	−0.016	−0.008
BMI (kg/m^2)	−0.234**	−0.170**	−0.200**	−0.131*	−0.058	−0.014
SBP (mmHg)	−0.219**	−0.183**	−0.170**	−0.090	0.006	0.033
DBP (mmHg)	−0.220**	−0.160**	−0.186**	−0.121	−0.027	−0.012
FPG (mmol/L)	−0.375**	−0.306**	−0.310**	−0.037	−0.042	−0.003
TG (mmol/L)	−0.214**	−0.178**	−0.172**	−0.120*	−0.046	−0.021
TC (mmol/L)	−0.318**	−0.279**	−0.248**	−0.067	−0.101	−0.045
HDL-C (mmol/L)	0.287**	0.139**	0.289**	0.050	−0.015	−0.037
LDL-C (mmol/L)	−0.311**	−0.257**	−0.252**	−0.027	−0.100	−0.060

Notes: *p<0.05, **p<0.01.

Abbreviations: BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FPG, fasting plasma glucose; TG, triglyceride; TC, total cholesterol; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; T-AMY, total amylase; P-AMY, pancreatic amylase; S-AMY, salivary amylase; AMY1, salivary amylase gene; AMY2A/ AMY2B, pancreatic amylase gene; CN, copy number.

Table 3 Receiver Operating Characteristic (ROC) Curve Analyses to Compare the Diagnostic Value of Amylase and Other Biomarkers for MetS

Factors	CUT OFF	AUC	p value	95% CI OF AUC		Sensitivity (%)	Specificity (%)
				Lower	Upper
T-AMY (U/L)	≤58	0.766	<0.001	0.726	0.805	71.33	68.85
P-AMY (U/L)	≤23	0.724	<0.001	0.681	0.767	81.33	54.62
S-AMY (U/L)	≤32	0.725	<0.001	0.683	0.767	65.10	71.92
ALT (U/L)	>20.5	0.736	<0.001	0.694	0.778	77.67	61.24
Uric acid (μmol/L)	>410.7	0.594	<0.001	0.546	0.642	94.67	23.35
GGT (U/L)	>22.1	0.843	<0.001	0.810	0.876	79.67	75.97

Abbreviations: T-AMY, total amylase; P-AMY, pancreatic amylase; S-AMY, salivary amylase; ALT, alanine aminotransferase; GGT, γ-glutamyl transpeptidase; AUC, area under the ROC curve; CI, confident interval.

Table 4 Logistic Regression Analysis of MetS and Low Total, Pancreatic, and Salivary Amylase Activity

		OR	95% CI for OR		p value
			Lower	Upper
	P-AMY	2.773	1.890	4.068	<0.001
MODEL 1	S-AMY	3.991	2.753	5.783	<0.001
	T-AMY	5.499	3.826	7.903	<0.001
	P-AMY	3.598	2.303	5.622	<0.001
MODEL 2	S-AMY	4.231	2.756	6.494	<0.001
	T-AMY	6.642	4.350	10.143	<0.001

Notes: Low serum T-, P-, and S-AMY activities were lower than the cut-off values (≤58, 23, and 32 U/L, respectively). Reference: serum T-, P-, and S-AMY activities higher than the cut-off values (>58, 23, and 32 U/L, respectively). Model 1: unadjusted. Model 2: adjusted for sex, age, and BMI.

Abbreviations: OR, odds ratio; CI, confidence interval; T-AMY, total amylase; P-AMY, pancreatic amylase; S-AMY, salivary amylase; BMI, body mass index.

Figure 1 Receiver operating characteristic (ROC) curve analyses were used to evaluate the diagnostic value of amylase for MetS. ROC curve analyses the diagnostic value of serum total amylase, serum salivary amylase, and pancreatic amylase (T-, S-, P-AMY) and other markers for MetS.

Figure 2 Mean AMY1/2A/2B gene copy number (CN) in different age groups. (A) The mean AMY1 gene CNs were compared between patients and healthy controls in different age groups (age <45 y and ≥45 y); (B) CNs of genes AMY2A and (C) AMY2B were compared between patients and healthy controls in different age groups (age <45 y and ≥45 y). The Asterisk indicates a significant difference (p < 0.05).