. Author manuscript; available in PMC: 2021 Aug 1.

Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2020 Nov 13;30(2):396–403. doi: 10.1158/1055-9965.EPI-20-0919

Table 1. Prevalence of gallstones among gallbladder cancer (GBC) case-control study participants.

Variable		Presence of gallstone
Variable		GBC (n=1,170) N (%)	Controls (n = 2,525) N (%)
Self-reported gallstone using stringent definition ^b		145 (12.4)	54 (2.1)
Self-reported gallstone history^a		468 (40.0)	60 (2.4)
Gender	Male	120 (25.6)	13 (21.7)
Gender	Female	348 (74.4)	47 (78.3)
Geographical regions	North	207 (44.2)	16 (26.7)
	North East	181 (38.7)	28 (46.7)
	South	1 (0.2)	1 (1.6)
	West	47 (10.0)	12 (20.0)
	Central	32 (6.8)	3 (5.0)

^aSelf-Reported Gallstone; reported by study participant as either present/not present.

^bSelf reported gallstone using stringent definition; Gallstone history was ascertained using definition of self-reported gallstone; however those gallstones diagnosed within a year prior to the date of diagnosis of gallbladder cancer for cases or within a year prior to the date of interview for controls were excluded from the analysis