Prevalence and risk factors of nonalcoholic fatty liver disease in a general population, the HUNT study

Figures & data

Figure 1. Flowchart of the selection of cases with NAFLD in the third Trøndelag Health Study (HUNT3), Norway. *Several participants with more than one diagnosis.

Table 1. Characteristics of cases with NAFLD and the reference population.

		Cases (n = 2373)		Reference population (n = 45,554)
Age (years)
	Mean (SD)	52.1	(14.0)	53.5	(16.1)
	Median (IQR)	53.7	(42.4–61.6)	53.8	(41.6–65.0)
Sex
	Women, no. (%)	1502	63.3	25,151	55.2
	Men, no. (%)	871	36.7	20,403	44.8
ALT (IU/L)
	Mean (SD)	80.1	(43.0)	25.6	(11.2)
	Median (IQR)	72.0	(54.0–88.0)	23.0	(18.0–31.0)
Tobacco smoking status
	Never, no. (%)	1018	42.9	19,147	42.0
	Previous, no. (%)	805	33.9	14,381	31.6
	Current, no. (%)	482	20.3	10,756	23.6
	Missing, no. (%)	68	2.9	1270	2.8
BMI (kg/m^2)
	Mean (SD)	29.6	(4.9)	27.0	(4.3)
	Median (IQR)	29.4	(26.2–32.6)	26.6	(24.0–29.5)
	<25.0, no. (%)	416	17.5	15,187	33.3
	25.0–29.9, no. (%)	889	37.5	20,251	44.5
	≥30.0, no. (%)	1052	44.3	9911	21.8
	Missing, no. (%)	16	0.7	205	0.5
Waist circumference (cm)
	Mean (SD)	99.6	(13.0)	93.2	(12.2)
	Median (IQR)	99.0	(91.0–108.0)	93.0	(85.0–101.0)
	Normal, no. (%)	292	12.3	12,783	28.1
	Increased, no. (%)	509	21.4	14,076	30.9
	Very increased, no. (%)	1562	65.8	18,439	40.5
	Missing, no. (%)	10	0.4	256	0.6
Hypertension
	Absent, no. (%)	807	34.0	20,742	45.5
	Present, no. (%)	1558	65.7	24,706	54.2
	Missing, no. (%)	8	0.3	106	0.2
Diabetes mellitus
	Absent, no. (%)	2023	85.3	41,791	91.7
	Present, no. (%)	349	14.7	3748	8.2
	Missing, no. (%)	1	0.0	15	0.0
Triglycerides (mmol/L)
	Mean (SD)	2.1	(1.3)	1.6	(1.0)
	Median (IQR)	1.8	(1.2–2.6)	1.4	(1.0–2.0)
	Normal, no. (%)	1090	45.9	29,077	63.8
	Elevated, no. (%)	1283	54.1	16,477	36.2
	Missing, no. (%)	0	0.0	0	0.0
Cholesterol (mmol/L)
	Mean (SD)	5.7	(1.2)	5.5	(1.1)
	Median (IQR)	5.6	(4.8–6.4)	5.4	(4.7–6.2)
	Normal, no. (%)	2165	91.2	43,003	94.4
	Elevated, no. (%)	176	7.4	1886	4.1
	Missing, no. (%)	32	1.3	665	1.5
HDL (mmol/L)
	Mean (SD)	1.3	(0.4)	1.4	(0.3)
	Median (IQR)	1.2	(1.0–1.5)	1.3	(1.1–1.6)
	Normal, no. (%)	1419	59.8	34,312	75.3
	Lowered, no. (%)	922	38.9	10,576	23.2
	Missing, no. (%)	32	1.3	666	1.5

ALT: alanine aminotransferase; HDL: high density lipoproteins; IQR: interquartile range; NAFLD: nonalcoholic fatty liver disease; SD: standard deviation.

Table 2. The risk of NAFLD.

		Univariable analysis		Multivariable analysis
		OR	95% CI	OR	95% CI
Age (years)
		0.99	(0.99–1.00)	0.98	(0.98–0.98)
Sex
	Women	1.00	(reference)	1.00	(reference)
	Men	0.71	(0.66–0.78)	0.71	(0.64–0.79)
Tobacco smoking status
	Never	1.00	(reference)	1.00	(reference)
	Previously	1.05	(0.96–1.16)	1.04	(0.94–1.15)
	Current	0.84	(0.75–0.94)	0.79	(0.70–0.89)
BMI (kg/m^2)
	<25	1.00	(reference)	1.00	(reference)
	25.0–29.9	1.60	(1.42–1.80)	1.09	(0.94–1.26)
	>30	3.88	(3.45–4.35)	1.73	(1.46–2.05)
	p for trend	<0.001		<0.001
Waist circumference
	Normal	1.00	(reference)	1.00	(reference)
	Increased	1.58	(1.37–1.83)	1.35	(1.15–1.59)
	Very increased	3.71	(3.27–4.21)	1.97	(1.65–2.35)
	p for trend	<0.001		<0.001
Hypertension
	Absent	1.00	(reference)	1.00	(reference)
	Present	1.62	(1.49–1.77)	1.58	(1.42–1.76)
Diabetes
	Absent	1.00	(reference)	1.00	(reference)
	Present	1.92	(1.71–2.17)	1.48	(1.30–1.68)
Triglycerides (mmol/L)
	Normal	1.00	(reference)	1.00	(reference)
	Elevated	2.08	(1.91–2.26)	1.55	(1.41–1.71)
Cholesterol (mmol/L)
	Normal	1.00	(reference)	1.00	(reference)
	Elevated	1.85	(1.58–2.18)	1.52	(1.29–1.81)
HDL (mmol/L)
	Normal	1.00	(reference)	1.00	(reference)
	Lowered	2.11	(1.93–2.30)	1.33	(1.21–1.47)

CI: confidence interval; HDL: high density lipoproteins; NAFLD: nonalcoholic fatty liver disease; OR: odds ratio.