Fatty liver is an independent risk factor for gallbladder polyps

Table 1 Age distribution of the whole study population and subjects with gallbladder polyps

Age (yr)	Whole study population (n = 13498)			Subjects with gallbladder polyps (n = 1405)
	Male	Female	Total	Male (%)	Female (%)	Total (%)
< 30	497	664	1161	57 (11.5)	34 (5.1)	91 (7.8)
30-39	1615	1590	3205	188 (11.6)	128 (8.1)	316 (9.9)
40-49	1915	1206	3121	286 (14.9)	134 (11.1)	420 (13.5)
50-59	1975	1512	3487	252 (12.8)	123 (8.1)	375 (10.8)
60-69	1013	829	1842	88 (8.7)	69 (8.3)	157 (8.5)
≥ 70	320	362	682	26 (8.1)	20 (5.5)	46 (6.7)
Total	7335	6163	13498	897 (12.2)	508 (8.2)	1405 (10.4)

Table 2 Comparison of baseline characteristics between the subjects with and without gallbladder polyps

Characteristics	GBP group (n = 1405)	Control group (n = 2810)	P value
Age (yr)	46.84 ± 11.72	46.84 ± 11.72	> 0.999
Gender (male, %)	897 (63.8%)	1794 (63.8%)	> 0.999
BMI (kg/m2)	23.93 ± 3.04	23.94 ± 3.34	0.866
Waist circumference (cm)	84.30 ± 9.04	84.36 ± 9.48	0.844
Visceral fat area (cm2)	92.38 ± 32.51	94.52 ± 38.50	0.059
ASM (kg)	20.88 ± 5.22	20.76 ± 5.00	0.452
Sarcopenia (%)	87 (6.2%)	215 (7.7%)	0.087
Hypertension (%)	643 (45.8%)	1273 (45.3%)	0.793
Diabetes (%)	116 (8.3%)	266 (9.5%)	0.211
Metabolic syndrome (%)	307 (21.9%)	626 (22.3%)	0.783
Fatty liver (%)	643 (45.8%)	1173 (41.7%)	0.013
Biochemistry
AST (IU/L)	26.02 ± 17.18	27.80 ± 15.39	0.001
ALT (IU/L)	26.50 ± 22.88	29.02 ± 22.00	0.001
Alkaline phosphatase (IU/L)	66.18 ± 18.63	67.22 ± 19.48	0.099
Gamma-glutamyltransferase (IU/L)	31.00 ± 66.11	33.99 ± 46.29	0.089
hs-CRP (mg/dL)	0.16 ± 0.65	0.14 ± 0.38	0.249
Total cholesterol (mg/dL)	195.29 ± 36.24	197.40 ± 35.75	0.071
Triglyceride (mg/dL)	113.40 ± 73.21	117.28 ± 79.25	0.125
HDL cholesterol (mg/dL)	54.98 ± 13.52	55.09 ± 13.76	0.812
CEA (ng/mL)	1.63 ± 1.05	1.61 ± 1.00	0.574
CA19-9 (IU/mL)	10.59 ± 9.17	10.80 ± 11.32	0.548
HBsAg (%)	53 (3.9%)	85 (3.1%)	0.200
HCV Ab (%)	5 (0.4%)	12 (0.4%)	> 0.999

Data are presented as mean± SD or number (%). GBP: Gallbladder polyp; BMI: Body mass index; ASM: Appendicular skeletal muscle mass; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; hs-CRP: High-sensitivity C-reactive protein; HDL: High-density lipoprotein; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; HBsAg: Hepatitis B virus surface antigen; HCV Ab: Hepatitis C virus antibody.

Table 3 Univariable analysis of the risk factors for gallbladder polyps

Variables	OR	95%CI	P value
BMI (kg/m2)
< 23	1.000
≥ 23, < 25	1.050	0.893-1.235	0.552
≥ 25	0.935	0.806-1.085	0.378
Waist circumference (cm)
≤ 90 (male), ≤ 80 (female)	1.000
> 90 (male), > 80 (female)	1.057	0.925-1.208	0.413
Hypertension
No	1.000
Yes	1.019	0.896-1.159	0.776
Diabetes
No	1.000
Yes	0.861	0.685-1.081	0.197
Metabolic syndrome
No	1.000
Yes	0.975	0.836-1.139	0.753
AST (IU/L)	0.991	0.986-0.996	0.001
ALT (IU/L)	0.994	0.991-0.998	0.001
Alkaline phosphatase (IU/L)	0.997	0.994-1.001	0.100
Gamma-glutamyltransferase (IU/L)	0.999	0.997-1.000	0.090
hs-CRP (mg/dL)	1.076	0.944-1.226	0.273
CEA (ng/mL)	1.018	0.956-1.085	0.574
CA19-9 (IU/mL)	0.998	0.992-1.004	0.549
HBsAg
No	1.000
Yes	1.255	0.885-1.779	0.203
HCV Ab
No	1.000
Yes	0.835	0.294-2.375	0.736
Total cholesterol (mg/dL)
< 200	1.000
200-240	0.948	0.824-1.091	0.459
≥ 240	0.875	0.708-1.080	0.213
Triglyceride (mg/dL)
< 150	1.000
≥ 150	0.932	0.798-1.088	0.372
HDL cholesterol (mg/dL)
> 40 (male), > 50 (female)	1.000
≤ 40 (male), ≤ 50 (female)	1.041	0.887-1.223	0.621
Sarcopenia
No	1.000
Yes	0.797	0.616-1.031	0.084
Visceral fat area (cm2)
Quartile I (male < 81.8, female < 55.2)	1.000
Quartile II (male 81.8-100.8, female 55.2-71.6)	1.069	0.890-1.283	0.477
Quartile III (male 100.8-121.8, female 71.6-92.5)	0.951	0.793-1.140	0.585
Quartile IV (male > 121.8, female > 92.5)	0.853	0.721-1.010	0.066
Fatty liver
No	1.000
Yes	1.178	1.035-1.340	0.013

OR: Odds ratio; CI: Confidence level; BMI: Body mass index; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; hs-CRP: High-sensitivity C-reactive protein; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; HBsAg: Hepatitis B virus surface antigen; HCV Ab: Hepatitis C virus antibody; HDL: High-density lipoprotein.

Table 4 Multivariable analysis of the risk factors for gallbladder polyps

Variables	OR	95%CI	P value
ALT (IU/L)	0.993	0.989-0.996	< 0.001
Fatty liver
No	1.000
Yes	1.413	1.218-1.638	< 0.001

OR: Odds ratio; CI: Confidence level; BMI: Body mass index; ALT: Alanine aminotransferase.

Table 5 Multivariable analysis of the association between gallbladder polyps and fatty liver grades according to gallbladder polyp size

Variables	OR	95%CI	P value
Total population
The presence of fatty liver	1.413	1.218-1.638	< 0.001
Fatty liver grade
No	1.000		< 0.0011
Mild	1.338	1.141-1.570	< 0.001
Moderate to severe	1.631	1.317-2.020	< 0.001
GBP ≥ 5 mm
The presence of fatty liver	1.629	1.335-1.988	< 0.001
Fatty liver grade
No	1.000		< 0.0011
Mild	1.523	1.228-1.888	< 0.001
Moderate to severe	2.137	1.662-2.749	< 0.001
GBP < 5 mm
The presence of fatty liver	1.318	1.085-1.602	0.005
Fatty liver grade
No	1.000		0.0381
Mild	1.315	1.072-1.613	0.009
Moderate to severe	1.332	0.990-1.792	0.058

¹P value for the test of trend of odds. OR: Odds ratio; CI: Confidence level; GBP: Gallbladder polyp.