(b) Colon and rectal cancers.

Studies	Location	Year of Publication	Sample Size	Study Design	Exposition Measurement	Site of Cancer	Subgroups Included in the Analysis	Effect Size and CI
Gottlieb and Carr [65]	Louisiana, USA	1982	546 cases and 534 controls	Case-control	Exposure to chlorinated drinking water	Rectal	n.d.	All: OR = 1.68 (1.17–2.42)
Koivusalo et al. [52]	Finland	1997	621 431	Cohort	Questionnaires. Information on water-pipe connections, past drinking water quality, and treatment practices by waterworks was obtained from administrative registers and municipal waterworks. The level of mutagenicity was estimated by modelling	Colon and rectal	Sex	Colon: All: RR = 0.90 (0.77–1.04); Men: RR = 0.83 (0.66–1.04); Women: RR = 0.95 (0.78–1.85). Rectal: All: RR = 1.04 (0.86–1.26); Men: RR = 0.85 (0.66–1.09); Women: RR = 1.38 (1.03–1.85).
Hildesheim et al. [66]	Iowa, USA	1998	560 colon cases, 537 rectal cases, and 1983 controls	Case-control	TTHMs in tap water	Colon and rectal	n.d.	Colon: OR = 1.06 (0.7–1.6); Rectal: OR = 1.66 (1.1–2.6)
King et al. [57]	Ontario, Canada	2000	767 colon cases, 661 rectal cases, and 1545 controls	Case-control	Questionnaire about source of water. Water source and chlorination status were provided directly by treatment plant surveys. TTHMs modelling	Colon and rectal	Sex	Colon: OR = 1.87 (1.15–3.05) for Men; OR = 0.92 (0.49–1.71) for Women. Rectal: OR = 0.98 (0.56–1.72) for Men; OR = 0.72 (0.34–1.53) for Women
Bove et al. [63]	New York State, USA	2007	128 cases and 253 controls	Case-control	TTHMs in tap water + water consumption	Rectal	n.d.	THM4: OR = 1.01 (0.98–1.03); CLF: OR = 1.00 (0.93–1.09); BRF: OR = 1.20 (1.05–1.35)
Kuo et al. [69]	Taiwan	2009	2195 cases and 2195 controls	Case-control	Questionnaire & data on TTHM levels in drinking water in study. Municipalities were collected from the Taiwan Environmental Protection Administration	Colon	n.d.	All: OR = 1.04 (0.89–1.21)

NB: n.d.: No data; OR: Odds Ratio; RR: Risk Ratio; CLF: Chloroform; BRF: Bromoform; BDCM: Bromodichloromethane.