Prevalence and risk factors of steatosis and advanced fibrosis using transient elastography in the United States’ adolescent population

Table 1 General characteristics of study population

	All participants (n = 740)
Age	15 (13-16)
Sex, n (%)
Male	386 (52.16)
Female	354 (47.84)
Race, n (%)
Mexican American	130 (17.57)
Other Hispanic	55 (7.43)
Non-Hispanic White	229 (30.95)
Non-Hispanic Black	171 (23.11)
Non-Hispanic Asian	83 (11.22)
Other race-including multi-racial	72 (9.73)
Smoking, n (%)	6 (0.84)
Steatosis grade, n (%)
S0	538 (72.8)
S1	63 (8.53)
S2	39 (5.28)
S3	99 (13.4)
Fibrosis result, n (%)
F0-F1	693 (93.65)
F2	26 (3.51)
F3	12 (1.62)
F4	9 (1.22)
Waist-to-height ratio	0.48 (0.43-0.55)
Waist-to-hip ratio	0.57 (0.53-0.63)
Body mass index, n (%)
Underweight	4 (0.54)
Normal	392 (53.33)
Risk of overweight	128 (17.41)
Overweight	211 (28.71)
Days physically active at least 60 min	4 (2-5)
Hours/day watch TV or videos past 30 d, n (%)
Less than 1 h	107 (14.72)
1 h	121 (16.64)
2 h	166 (22.83)
3 h	105 (14.44)
4 h	78 (10.73)
5 h or more	150 (20.63)
Hours/day use computer past 30 d, n (%)
Less than 1 h	68 (9.34)
1 h	85 (11.68)
2 h	131 (17.99)
3 h	83 (11.4)
4 h	100 (13.74)
5 h or more	261 (35.85)

Table 2 Univariate Analysis of participant characteristics and steatosis grade

	Steatosis grade				Coefficient	P value
	S0 (n = 538)	S1 (n = 63)	S2 (n = 39)	S3 (n = 99)
Age	14 (13-16)	14 (13-16)	15 (14-16)	15 (14-16)	0.0562	0.016a
Sex
Male	273 (50.74%)	29 (46.03%)	20 (51.28%)	64 (64.65%)	0.1747	0.027 a
Female	265 (49.26%)	34 (53.97%)	19 (48.72%)	35 (35.35%)
Race
Mexican American	82 (15.24%)	11 (17.46%)	7 (17.95%)	30 (30.3%)	0.3542	< 0.001a
Other Hispanic	42 (7.81%)	5 (7.94%)	1 (2.56%)	7 (7.07%)	-0.0903	0.549
Non-Hispanic White	178 (33.09%)	18 (28.57%)	13 (33.33%)	20 (20.2%)	-0.2008	0.019 a
Non-Hispanic Black	128 (23.79%)	10 (15.87%)	11 (28.21%)	21 (21.21%)	-0.0440	0.640
Non-Hispanic Asian	60 (11.15%)	8 (12.7%)	4 (10.26%)	11 (11.11%)	-0.0026	0.983
Other Race-Including Multi-Racial	48 (8.92%)	11 (17.46%)	3 (7.69%)	10 (10.1%)	0.0666	0.618
Smoking	4 (0.77%)	1 (1.59%)	0 (0%)	1 (1.04%)	0.0732	0.868
Waist-to-height ratio	0.45 (0.42-0.51)	0.54 (0.47-0.59)	0.57 (0.48-0.62)	0.6 (0.55-0.66)	6.5565	< 0.001a
Waist-to-hip ratio	0.56 (0.52-0.6)	0.6 (0.57-0.65)	0.63 (0.57-0.68)	0.64 (0.61-0.69)	6.6835	< 0.001a
Body mass index					0.6128	< 0.001a
Underweight	4 (0.75%)	0 (0%)	0 (0%)	0 (0%)
Normal	349 (65.48%)	22 (34.92%)	10 (25.64%)	10 (10.1%)
Risk of overweight	97 (18.2%)	14 (22.22%)	8 (20.51%)	9 (9.09%)
Overweight	83 (15.57%)	27 (42.86%)	21 (53.85%)	80 (80.81%)
Days physically active at least 60 min	4 (2-6)	3.5 (1-5)	4 (2-5)	4 (2-5)	-0.0167	0.348
Hours/day watch TV or videos past 30 d	2 (1-4)	2 (1-4)	3 (1.75-5)	2 (1-4.25)	0.0421	0.070
Hours/day use computer past 30 d	3 (2-5)	4 (2-5)	5 (2-5)	4 (2-5)	0.0560	0.014a
Diet
Energy (1000 kcal)	1.82 (1.43-2.45)	1.75 (1.26-2.28)	1.62 (1.33-2)	1.71 (1.34-2.38)	-0.0732	0.145
Protein (mg)	63.59 (48.32-86.06)	63.15 (40.29-77.27)	53.38 (37.92-80.78)	64.1 (49.36-87.48)	-0.0732	0.145
Carbohydrate (mg)	230.94 (180.54-301.73)	233.36 (154.21-296.51)	213.08 (169.63-253.71)	219.06 (173.09-290.58)	-0.0005	0.178
Total sugars (mg)	94.74 (67.04-133.77)	89.84 (54.32-140.86)	75.37 (51.43-97.67)	90.5 (63.35-127.21)	-0.0008	0.224
Dietary fiber (mg)	12.85 (9.25-17.36)	12.2 (8.77-18.3)	12.5 (9.24-16.79)	12.2 (8.8-16.4)	-0.0051	0.368
Total fat (mg)	75.09 (55.41-97.52)	66.13 (43.61-93.44)	62.68 (45.53-83.34)	71.58 (47.42-95.31)	-0.0016	0.143
Total saturated fatty acids (mg)	25.07 (17.39-35.43)	24.43 (11.47-32.25)	18.7 (11.7-30.89)	22.91 (14.97-31.11)	-0.0044	0.122
Cholesterol (mg)	197 (132.88-320.5)	165 (90.25-305.5)	162 (72.38-283.63)	199 (134-279.25)	-0.0003	0.254
Systolic blood pressure (mm Hg)	106 (100-114)	108 (103.5-114.5)	112 (104-120)	112 (104-120)	0.0254	< 0.001a
Diastolic blood pressure (mm Hg)	62 (54-68)	60 (51.5-68)	62 (55.5-70)	60 (54-66)	-0.0038	0.222
Triglycerides, refrig serum (mg/dL)1	74 (57-98)	79 (62-103)	78.5 (70-105.5)	98 (68-159)	0.0051	< 0.001a
Uric acid (mg/dL)	4.7 (4-5.6)	5.1 (4.15-6.05)	5.45 (4.65-6.15)	5.75 (4.7-6.7)	0.1984	< 0.001a
Aspartate aminotransferase (IU/L)1	18 (16-22)	18 (15.25-21.75)	16.5 (15-21)	20.5 (18-27)	0.0151	0.002a
Alanine aminotransferase (IU/L)1	12 (10-15)	15 (11.25-19)	14 (10-17.5)	20.5 (14-34)	0.0372	< 0.001a
Gamma glutamyl transferase (IU/L)1	12 (10-15)	12 (10-18.75)	15.5 (10-19)	18 (12-24)	0.0375	< 0.001a
Alkaline phosphatase (ALP) (IU/L)	130 (87-225.75)	121 (86.75-235)	135 (75.5-188)	126.5 (99-188)	-0.0003	0.537
Total bilirubin (mg/dL)1	0.4 (0.3-0.6)	0.3 (0.23-0.48)	0.4 (0.3-0.5)	0.4 (0.3-0.4)	-0.3419	0.009a
Total protein (g/dL)	7.3 (7-7.5)	7.3 (7-7.5)	7.35 (7.15-7.6)	7.35 (7.2-7.6)	0.3620	0.002a
Albumin, refrigerated serum (g/dL)	4.3 (4.1-4.5)	4.3 (4.1-4.5)	4.25 (4.05-4.45)	4.2 (4-4.4)	-0.5553	< 0.001a
Iron frozen, serum (μg/dL)	85 (61-113)	86 (58.25-105.75)	69 (49.5-85.75)	75 (56-103)	-0.0027	0.013a
Total iron binding capacity (μg/dL)	348 (317.5-382)	366 (342-392.25)	360 (326.25-406.5)	356 (322-385)	0.0015	0.092
Transferrin Saturation (%)	24 (17-33)	23 (15.25-30.75)	19 (13.5-26)	22.5 (15-30)	-0.0104	0.004a
Ferritin (ng/mL)	39.2 (24.85-59.85)	35.25 (18.75-57.5)	30.85 (14.65-60.15)	59.2 (35-93.12)	0.0038	< 0.001a
Total cholesterol (mg/dL)	150 (134-168)	158 (132.75-174)	152 (139.5-166.25)	157 (139.25-178.75)	0.0032	0.035a
Low-density lipoprotein cholesterol (mg/dL)	78.8 (64.8-94.6)	85.8 (69.15-107.45)	82.5 (70.1-97.8)	87 (70.6-103.6)	0.0041	0.019a
Direct high-density lipoprotein cholesterol (mg/dL)	53 (46-61)	50 (46-56)	48 (41.5-55)	44 (39-51)	-0.0238	< 0.001a
HS C-reactive protein (mg/L)1	0.49 (0.32-1.01)	0.72 (0.35-1.51)	0.95 (0.43-1.89)	1.76 (0.87-3.74)	0.0448	< 0.001a
Platelet count (1000 cells/uL)	258 (228-292)	269 (228.5-318.5)	273 (239-307)	282 (248-313)	0.0026	< 0.001a
Hemoglobin A1c (%)1	5.3 (5.1-5.5)	5.3 (5.1-5.45)	5.3 (5.1-5.6)	5.4 (5.2-5.5)	0.2280	0.054
Fasting glucose (mg/dL)	97 (93-101)	98 (93.25-101.75)	101 (94-103)	99.5 (96-103)	0.0219	0.017a
Insulin (pmol/L)	54.96 (39.84-79.38)	101.1 (71.58-130.8)	88.32 (62.28-118.14)	129.63 (75.66-185.46)	0.0086	< 0.001a
Homeostatic model assessment for insulin resistance	2.23 (1.58-3.32)	4.08 (2.96-5.47)	3.56 (2.64-4.96)	5.34 (3.08-7.78)	0.1976	< 0.001a

¹Skewness > 3.

^aP < 0.05. HS: High sensitivity.

Table 3 Predictors of steatosis grade in multivariate level

Predictors	Coefficient (standard error)	P value
Alanine aminotransferase (IU/L)1	0.3912 (0.1159)	0.001
Homestatic model assessment for insulin resistance	0.0684 (0.0247)	0.006
Waist-to-height ratio	3.2299 (0.0912)	0.001
Body mass index	0.2335 (0.0912)	0.011

¹Log-transformed predictor. Number of observations = 307; Adjusted R² = 0.37;

Table 4 Univariate Analysis of participant characteristics and fibrosis stage

	Fibrosis stage				Coefficient	P value
	F0 - F1 (n = 693)	F2 (n = 26)	F3 (n = 12)	F4 (n = 9)
Age	15 (13-16)	15 (13-17)	14 (13-15)	15 (14.75-17)	0.0106	0.276
Sex
Male	356 (51.37%)	17 (65.38%)	6 (50%)	7 (77.78%)	0.0533	0.105
Female	337 (48.63%)	9 (34.62%)	6 (50%)	2 (22.22%)
Race
Mexican American	123 (17.75%)	4 (15.38%)	0 (0%)	3 (33.33%)	-0.0049	0.909
Other Hispanic	53 (7.65%)	1 (3.85%)	1 (8.33%)	0 (0%)	-0.0535	0.393
Non-Hispanic White	222 (32.03%)	3 (11.54%)	2 (16.67%)	2 (22.22%)	-0.0685	0.054
Non-Hispanic Black	148 (21.36%)	13 (50%)	8 (66.67%)	2 (22.22%)	0.1309	< 0.001a
Non-Hispanic Asian	78 (11.26%)	4 (15.38%)	0 (0%)	1 (11.11%)	-0.0222	0.669
Other Race-Including Multi-Racial	69 (9.96%)	1 (3.85%)	1 (8.33%)	1 (11.11%)	-0.0230	0.679
Smoking	5 (0.75%)	0 (0%)	0 (0%)	1 (11.11%)	0.3967	0.032a
Waist-to-height ratio	0.48 (0.43-0.55)	0.49 (0.44-0.61)	0.49 (0.4-0.61)	0.5 (0.42-0.68)	0.3746	0.042a
Waist-to-hip ratio	0.57 (0.53-0.62)	0.59 (0.54-0.69)	0.6 (0.52-0.64)	0.59 (0.5-0.7)	0.2804	0.215
Body mass index					0.0330	0.079
Underweight	4 (0.58%)	0 (0%)	0 (0%)	0 (0%)
Normal	370 (53.78%)	11 (42.31%)	6 (50%)	5 (55.56%)
Risk of overweight	126 (18.31%)	2 (7.69%)	0 (0%)	0 (0%)
Overweight	188 (27.33%)	13 (50%)	6 (50%)	4 (44.44%)
Days physically active at least 60 min	4 (2-5)	4 (2-5)	2.5 (0.5-6)	5 (2.5-6)	-0.0039	0.597
Hours/day watch TV or videos past 30 d	2 (1-4)	2 (1-4)	2.5 (2-4.5)	2 (0-3.5)	-0.0027	0.779
Hours/day use computer past 30 d	3 (2-5)	5 (3-5)	4 (2.5-5)	3 (0.75-5)	0.0062	0.519
Steatosis grade					0.0757	< 0.001a
S0	518 (74.86%)	13 (50%)	3 (25%)	4 (44.44%)
S1	57 (8.24%)	2 (7.69%)	3 (25%)	1 (11.11%)
S2	35 (5.06%)	2 (7.69%)	2 (16.67%)	0 (0%)
S3	82 (11.85%)	9 (34.62%)	4 (33.33%)	4 (44.44%)
Diet
Energy (1000 kcal)	1.8 (1.4-2.42)	1.5 (1.37-2.11)	1.62 (1.4-1.75)	1.75 (1.32-2.4)	-0.0225	0.282
Protein (mg)	63.69 (46.81-85.41)	50.66 (42.74-94.29)	59.33 (45.9-76.55)	68.03 (49.61-73.78)	-0.0004	0.405
Carbohydrate (mg)	230.55 (174.26-299.84)	202.56 (152.11-255.23)	204.26 (177.87-238.7)	242.27 (186.12-305.52)	-0.0001	0.671
Total sugars (mg)	92.59 (64.25-133.63)	87.43 (58.07-120.32)	75.76 (62.31-94.74)	94.74 (85.8-123.02)	-0.0001	0.697
Dietary fiber (mg)	12.7 (9.25-17.1)	10.8 (7.62-17.64)	10.4 (9.02-14.29)	12.85 (10.8-16.96)	-0.0018	0.461
Total fat (mg)	74.07 (52.04-97.34)	55.7 (45.07-79.29)	65.98 (50.43-78.07)	69.09 (45.95-97.94)	-0.0007	0.091
Total saturated fatty acids (mg)	24.72 (16.8-34.81)	21.06 (14.84-29.88)	23.04 (18.87-27.64)	22.84 (18.35-28.35)	-0.0020	0.083
Cholesterol (mg)	197 (129.13-317.63)	150.5 (85-213.25)	162.5 (118.38-228.88)	146.5 (124.75-310.25)	-0.0002	0.065
Systolic blood pressure (mmHg)	106 (102-114)	108 (103.5-126.5)	108 (100.5-120)	116 (113-122)	0.0066	< 0.001a
Diastolic blood pressure (mmHg)	62 (54-68)	64 (53-71)	56 (50.5-65.5)	60 (56-68)	-0.0001	0.967
Triglycerides, refrig serum (mg/dL)1	78 (61-104)	67.5 (50-111)	88 (61.75-161)	88.5 (56.5-121.5)	0.0276	0.471
Uric acid (mg/dL)	4.9 (4.1-5.8)	5 (3.7-6)	4.7 (3.3-5.98)	5.75 (4.2-7.45)	0.0079	0.560
Aspartate aminotransferase (IU/L)1	18 (16-22)	18 (15-25)	15 (14-23)	29 (20-32)	0.0882	0.137
Alanine aminotransferase (IU/L)1	13 (10-17)	14 (9-20)	12 (9.5-15)	20.5 (15-37.5)	0.0738	0.046a
Gamma glutamyl transferase (IU/L)1	13 (10-17)	12 (9-16)	12 (10-19.5)	20.5 (14-32.5)	0.0047	0.018a
Alkaline phosphatase (IU/L)	129 (88-222.5)	121.5 (81-205)	187 (127.75-242.75)	113 (105-129.5)	-0.0001	0.470
Total bilirubin (mg/dL)1	0.4 (0.3-0.5)	0.3 (0.2-0.6)	0.4 (0.3-0.5)	0.45 (0.35-0.7)	0.0178	0.577
Total protein (g/dL)	7.3 (7-7.5)	7.15 (6.8-7.3)	7.3 (7-7.63)	7.2 (7.15-7.45)	-0.0156	0.745
Albumin, refrigerated serum (g/dL)	4.3 (4.1-4.5)	4.05 (3.8-4.4)	4.2 (4.03-4.3)	4.3 (4.1-4.65)	-0.0744	0.229
Iron frozen, Serum (μg/dL)	83 (59-112)	80.5 (47-88)	88 (68-106)	67.5 (58-120.5)	0.0001	0.777
Total iron binding capacity (μg/dL)	352 (322-387)	346 (314-378)	355 (315.25-375.25)	314 (310-327.5)	-0.0009	0.018a
Transferrin saturation (%)	23 (17-32)	22 (15-26)	28 (19.25-31.5)	20 (18-39)	0.0013	0.377
Ferritin (ng/mL)	39.3 (24.5-62.1)	45.55 (24.45-61.85)	56.25 (29-71)	102.35 (35.75-141)	0.0009	0.030a
Total cholesterol (mg/dL)	151 (134-171)	140.5 (136-156)	161 (143-175)	131 (119-147.5)	-0.0010	0.102
Low-density lipoprotein cholesterol (mg/dL)	81 (66.2-97.6)	77.5 (64.2-92.6)	88.2 (71.6-91.4)	57.2 (55.5-80.1)	-0.0013	0.082
Direct high-density lipoprotein cholesterol (mg/dL)	51 (44-59)	49.5 (44-58)	50 (46-62)	49.5 (39-56)	-0.0012	0.426
HS C-reactive protein (mg/L)1	0.57 (0.35-1.39)	0.83 (0.34-1.34)	0.72 (0.37-1.12)	0.97 (0.53-7.09)	0.0240	0.134
Platelet count (1000 cells/uL)	262 (230-297.5)	275.5 (242-302.5)	262.5 (226-277)	262.5 (234-275)	-0.0001	0.769
Hemoglobin A1c (%)1	5.3 (5.1-5.5)	5.3 (5.25-5.6)	5.45 (5.25-5.65)	5.35 (5.15-5.6)	0.4629	0.098
Fasting glucose (mg/dL)	98 (94-102)	99 (94-103)	101 (95.5-104.25)	92 (89.75-95.75)	-0.0031	0.490
Insulin (pmol/L)	64.83 (43.38-99)	70.26 (45.87-183.17)	87.06 (59.28-160.28)	51.42 (27.29-127.14)	0.0005	0.291
Homeostatic model assessment for insulin resistance	2.61 (1.71-3.96)	2.66 (1.96-7.9)	4.08 (2.34-6.66)	1.95 (1.1-4.95)	0.0101	0.383

¹Skewness > 3.

^aP < 0.05. HS: High sensitivity.

Table 5 Predictors of fibrosis stage in multivariate level

Predictors	Coefficient (standard error)	P value
Steatosis grade	0.0730 (0.0172)	< 0.001
Race: Non-Hispanic Black	0.1352 (0.0430)	0.002
Smoke	0.4065 (0.1845)	0.028
Systolic blood pressure (mmHg)	0.0040 (0.0019)	0.035

Number of observations = 643; Adjusted R² = 0.0598.

Table 6 Predictive performance of liver fibrosis indices

Liver fibrosis indices (Predictor)		Outcome	Predictive performance
Index	Cutoff		Accuracy	PPV	NPV	Sensitivity	Specificity
APRI	0.7	F4	98.45%	0%	98.8%	0.0%	99.7%
FIB4	1.3	F4	98.61%	0%	98.8%	0.0%	99.8%
PNFI	9	F4	85.31%	3.26%	99.1%	37.5%	85.9%
PNFI	3	S1-S3	85.60%	83.33%	86.2%	59.7%	95.5%

APRI: Aspartate aminotransferase to platelet ratio index; FIB4: Fibrosis-4 index; NPV: Negative predictive value; PNFI: Pediatric non-alcoholic fatty liver disease fibrosis index; PPV: Positive predictive value.