Table 1. A summary of studies on the association between pickled vegetables and risk of oesophageal cancer.

Study/Literature	Study place (period)	Case/control	Studied variable	Consumption rate/Matched/Adjusteda	Study design
Kinjo et al, 1998/E	Japan; Kagoshima, Okayama, Hyogo, Osaka, Aichi, Miyagi (1966–1981)	440/220 272	Pickles	No/No/Yes	Cohort; the outcome was oesophageal cancer death
Zhang et al, 2000/C	China; Cixian (1973–1997)	350/350	P. V.	Yes/Yes/No	P-B CCS
Tao et al, 1999/E	China; Shanghai (1984–1988)	71/1122	P. V.	Yes/No/Yes	Nested CCS (only men); the outcome was oesophageal cancer death
Hu et al, 1994/E	China; Heilongjiang (1985–1989)	196/392	P. Chinese cabbage	No/Yes/Yes	H-B CCS
Tran et al, 2005/E	China; Linxian (1986–2001)	1958/29 584	P. V.	No/No/Yes	Cohort
Ren and Han, 1991/C	China; Tangshan (1987–1989)	112/112	P. V.	Yes/Yes/Yes	H-B CCS
Wang et al, 1992 (Study I)/E	China; Shanxi: high-risk area (1988–1989)	210/396	P. V. juice	Yes/Yes/Yes	CCS; H-B cases, P-B controls
Wang et al, 1992 (Study II)/E	China; Shanxi: moderate-risk area (1988–1989)	116/396	P. V. juice	Yes/Yes/Yes	CCS; H-B cases, P-B controls
Chu et al, 1993/C	China; Huaian (1988–1989)	151/151	P. V.	Yes/Yes/Nob	P-B CCS
Liu et al, 2001a/C	China; Tianjin (1988–1989)	165/165	P. V.	Yes/Yes/No	P-B CCS (only men)
Cheng et al, 1992/E	Hong Kong (1989–1990)	400/1598	P. V.	Yes/Yes/Yes	H-B CCS
Wang et al, 1993/C	China; Yanting (1990–1991)	155/155	P. V.	No/Yes/Yes	H-B CCS
Chen et al, 1995/C	China; Jintang (1990–1992)	148/296	P. V.	Yes/Yes/No	P-B CCS
Shen et al, 1997/C	China; Huaian (1993–1994)	158/158	P. V.	Yes/Yes/Nob	P-B CCS
Wang et al, 1999/C	China; Yangzhong (1994–1995)	68/68	P. V.	No/Yes/Yes	H-B CCS
Gao et al, 1999/E	China; Yangzhong (1995)	81/234	P. V.	Yes/Yes/Yes	P-B CCS
Ji, 1999/C	China; Linxian (1995–1996)	67/65	P. V.	Yes/No/Yes	H-B CCS
Chen et al, 2003/C	China; Linxian (1995–1997)	702/702	P. V.	No/Yes/Yes	P-B CCS
Huang et al, 2000/C	China; Meizhou (1996–1999)	150/150	P. V.	No/Yes/Yes	H-B CCS
Takezaki et al, 2001/E	China; Pizhou (1996–2000)	199/333	P. V.	No/No/Yes	CCS; H-B cases, P-B controls
Hung et al, 2004/E	Taiwan (1996–2002)	364/532	Preserved and P. V.	Yes/Yes/Yes	H-B CCS (only men)
Chen et al, 2000/C	China; Rugao (1997–1998)	100/100	P. V.	No/Yes/No	H-B CCS
Phukan et al, 2001/E	India; Assam (1997–1998)	502/1004	Pickles	Yes/Yes/Yes	H-B CCS
Li and Yu, 2003/E	China; Chaoshan (1997–2000)	1248/1248	Pickles	No/Yes/Yes	H-B CCS
Xibib et al, 2003/E	China; Linxian (1998–2000)	211/633	Salted or P. V.	No/Yes/Yes	P-B CCS
Qi et al, 2001/C	China; Pizhou (1999)	103/103	P. V.	No/Yes/Yes	P-B CCS
Liu et al, 2001b/C	China; Tianjin (1999)	86/158	P. V.	No/No/Yes	P-B CCS
Gao et al, 2001/C	China; Huai’an (1999–2000)	93/98	P. V.	No/Yes/Yes	H-B CCS
Chen et al, 2004/C	China; Rugao (1999–2000)	100/100	P. V.	No/Yes/Yes	H-B CCS
Chitra et al, 2004/E	India; Coimbatore (1999–2000)	90/90	Pickles	Yes/Yes/No	H-B CCS
Peng et al, 2005/C	China; Anxi (2001–2002)	237/237	P. V.	No/Yes/Yes	H-B CCS
Feng et al, 2008b/C	China; Changzhi (2001–2005)	201/201	P. V.	Yes/Yes/No	H-B CCS
Yang et al, 2005/E	China; Yanting (2003–2004)	185/185	P. V.	Yes/Yes/Yes	CCS; H-B cases, P-B controls
Zhao et al, 2003/C	China; Feicheng (not reported)	217/212	P. V.	Yes/No/Yes	CCS. Origin of cases was not reported. Controls were healthy residents in a high-risk village

Abbreviations: C=Chinese; CCS=case–control study; E=English; H-B=hospital-based; P=pickled; P-B=population-based; V=vegetable.

^aThis column shows whether the proportion of cases and controls who consumed the studied variables were reported/group- or individual-matching of controls to cases for age/reporting adjusted ORs for the association between consumption of pickled vegetables and cancer.

^bAdjusted ORs were also reported for these studies but because 95% CIs were not presented (Supplementary Table 1), we included their univariate results in the meta-analysis.