Central obesity and nonalcoholic fatty liver disease risk after adjusting for body mass index

Table 1 Baseline characteristics for studies included in meta-analysis

First author and year	Country	Case, n (M/W)	Control, n (M/W)	Design	Excluding1	Cut-off	Adjusted factors	NOS
High vs low category in waist circumference
Zelber-Sagi et al[27]	Israel	66/32	108/120	c-s	Hep B, C, DILI	102/88	5	8
Park et al[28]	Korea	62/84	118/86	c-s	Hep B, C	90/80	11	6
Choi et al[29]	Korea	246/68	216/129	c-s	Hep B, C	90/80	7	6
Tsai et al[30]	Taiwan	253/120	275/228	c-s	None	90/80	7	7
Kogiso et al[31]	Japan	33/24	60/113	c-s	Hep B, C	85/90	10	7
Das et al[32]	India	89/75	926/821	n-c-c	Hep B, C, DILI	90/80	6	8
Pinidiyapathirage et al[33]	Sri Lanka	45/27	144/185	c-s	Hep B, C	90/80	4	8
High vs low category in waist-to-hip ratio
Kogiso et al[31]	Japan	33/24	60/113	c-s	Hep B, C	0.845/0.845	10	7
Zheng et al[34]	China	189/61	192/48	c-c	Hep B, C	0.900/0.850	8	7
Wengert et al[35]	Germany	58/22	138/125	c-s	Hep B, C	NR	8	9
Per-unit increase in waist circumference
Yoon et al[36]	Korea	11/27	15/38	c-s	Other liver diseases	/	3	7
Church et al[22]	USA	24/0	218/0	n-c-c	Other liver diseases	/	3	7
Sung et al[37]	Korea	7155/1867	10461/11757	c-s	Hep B, C, DILI	/	2	6
Seo et al[20]	Korea	45/28	50/36	c-c	Hep B, C, DILI	/	12	8
Xu et al[38]	China	139/88	416/235	c-s	Other liver diseases	/	7	7
Sathiaraj et al[39]	India	77/21	75/27	c-c	Hep B, C, DILI	/	2	6
Zhou et al[40]	China	211	513	Cohort	Other liver diseases	/	11	8
Eshraghian et al[21]	Iran	127	705	c-s	DILI, other liver diseases	/	12	7
Cheah et al[41]	Malaysia	17/17	19/24	c-s	None	/	9	8
Foster et al[42]	USA	227/294	1144/1391	c-s	DILI, other liver diseases	/	9	7
Li et al[23]	China	28/51	130/233	Cohort	Other fatty liver	/	17	8

¹In addition to exclusion of alcoholic liver disease. c-c: Case-control; c-s: Cross-sectional; DILI: Drug-induced liver injury; Hep: Hepatitis; M: Men; n-c-c: Nested case-control; NOS: Newcastle-Ottawa scale; NR: Not reported; W: Women.

Table 2 Subgroup and meta-regression analyses of waist circumference and the risk of nonalcoholic fatty liver disease

Covariates	Subgroup	Studies, n	OR(95%CI)	P of Q	I2	Inter-groupP value	UnivariateP value	MultivariateP value
Per-unit increase in waist circumference
Region	East	9	1.076 (1.025-1.129)	0.000	73.6	0.006	0.171	0.214
	West	2	1.031 (1.016-1.046)	0.535	0.0
Design	c-s	8	1.063 (1.014-1.114)	0.000	79.1	0.157	0.764	0.984
	Others	3	1.071 (1.026-1.119)	0.254	26.9
Adjusted	Yes	7	1.051 (1.019-1.084)	0.035	55.8	0.031	0.489	0.770
(> 3 confounders)	No	4	1.126 (1.000-1.269)	0.000	85.0
Individuals	Yes	6	1.054 (1.025-1.083)	0.055	56.7	0.163	0.728	0.975
(> 700)	No	5	1.100 (0.991-1.22)	0.000	81.5
High vs low category of waist circumference
Design	c-s	5	2.113 (1.615-2.765)	0.180	36.2	0.057	0.642	0.947
	Others	2	4.072 (2.189-7.575)	0.512	0.0
Individuals	Yes	3	2.070 (1.546-2.774)	0.245	28.9	0.122	0.635	0.942
(> 600)	No	4	3.185 (2.010-5.046)	0.164	41.2

Table 3 Further analyses after adding several studies

Covariates	Subgroup	n of studies	OR(95%CI)	P of Q	I2	Inter-studyP value	UnivariateP value	MultivariateP value
Per-unit increase in waist circumference
Region	East	15	1.089 (1.057-1.122)	0.000	94.1	0.001	0.180	0.145
	West	5	1.040 (1.028-1.052)	0.149	40.8
Design	c-s	14	1.067 (1.042-1.193)	0.000	94.6	0.010	0.734	0.968
	Others	6	1.076 (1.049-1.103)	0.140	39.8
Adjusted	Yes	11	1.059 (1.038-1.081)	0.000	82.9	0.806	0.393	/
(> 3 factors)	No	9	1.101 (1.055-1149)	0.000	95.9
Adjusting for BMI	Yes	14	1.064 (1.040-1.089)	0.000	84.8	0.000	0.649	0.918
	No	6	1.086 (1.046-1.127)	0.000	95.3
Excluding ALD	Yes	16	1.079 (1.051-1.107)	0.000	90.0	0.000	0.603	0.869
	No	4	1.056 (1.022-1.093)	0.000	93.8
High vs low category of waist circumference
Region	East	11	2.687 (2.018-3.579)	0.000	74.4	0.000	0.545	0.934
	West	5	3.098 (2.005-4.785)	0.000	83.3
Design	c-s	12	2.471 (1.958-3.119)	0.000	72.3	0.000	0.015	0.078
	Other	4	5.212 (2.121-12.807)	0.858	0.0
Adjusted	Yes	10	3.002 (2.268-3.973)	0.000	73.1	0.000	0.459	/
(> 3 factors)	No	6	2.840 (2.184-3.691)	0.000	75.2
Adjusting for BMI	Yes	10	2.492 (1.898-3.271)	0.002	65.8	0.000	0.221	0.591
	No	6	3.281 (2.308-4.664)	0.000	79.5
Excluding ALD	Yes	12	2.856 (2.115-3.855)	0.000	74.9	0.000	0.910	1.000
	No	4	2.794 (1.716-4.549)	0.000	89.5

Table 4 Summary estimates by fixed- vs random-effects methods

	OR (95%CI)
	Fixed-effects	Random-effects
Categorical variable
WC	2.344 (1.831-3.000)	2.550 (1.799-3.615)
WHR	3.910 (2.255-6.780)	4.061 (1.529-10.790)
BMI	2.183 (1.582-3.013)	2.854 (1.604-5.080)
WC1	2.844 (2.082-3.885)	3.139 (2.067-4.767)
Per-unit increase
WC	1.043 (1.031-1.055)	1.065 (1.029-1.103)
BMI	1.121 (1.093-1.150)	1.250 (1.131-1.382)

¹Pooled same studies from above body mass index (BMI) category.