Table II.

Trends in mean ALT and in the prevalence of suspected NAFLD among US adolescents (12–19 y) by race/ethnicity, sex, and weight status, NHANES 1988–1994 to 2009–2010

	1988–1994	1999–2002	2003–2006	2007–2010	P = trend
All adolescents	N = 2739	N = 4004	N = 3824	N = 2138
ALT, mean, U/L	13.3 (0.3)	19.1 (0.4)	19.7 (0.2)	19.8 (0.3)	<.0001
Suspected NAFLD,* %	3.9 (0.5)	9.1 (0.8)	10.4 (0.9)	10.7 (0.9)	<.0001
Prevalence of suspected NAFLD* by adolescent subgroup
	N = 708	N = 962	N = 989	N = 673
Non-Hispanic white, %	4.5 (0.8)	7.4 (1.1)	9.7 (1.1)	10.1 (1.4)	.0006
	N = 946	N = 1167	N = 1342	N = 494
Non-Hispanic black, %	1.9 (0.6)	7.6 (0.9)	7.8 (0.8)	9.7 (1.4)	<.0001
	N = 953	N = 1536	N = 1218	N = 577
Mexican American, %	5.4 (0.8)	15.4 (1.1)	14.9 (0.9)	15.2 (1.5)	<.0001
	N = 1280	N = 2011	N = 1956	N = 1159
Males, %	5.6 (1.1)	12.1 (1.2)	14.6 (1.3)	14.7 (1.3)	<.0001
	N = 1459	N = 1993	N = 1868	N = 979
Females, %	2.1 (0.6)	5.9 (0.8)	5.8 (0.7)	6.3 (0.9)	.002
	N = 458	N = 689	N = 672	N = 392
Overweight (BMI 85th – <95th percentile), %	10.1 (2.3)	20.5 (2.5)	17.8 (1.8)	17.2 (2.6)	.14
	N = 393	N = 843	N = 43	N = 482
Obese (BMI ≥95th percentile), %	20.7 (3.6)	32.4 (2.4)	37.9 (2.6)	38.2 (2.9)	<.0001
	N = 67	N = 184	N = 214	N = 133
Severely obese (BMI ≥99th percentile), %	27.2 (10.0)	52.1 (5.2)	58.8 (4.1)	51.6 (7.2)	.03

All results are proportions with SE unless indicated as a mean.

^*Suspected NAFLD = overweight or obesity + ALT >25.8 boys or >22.1 for girls.