Table 1.

Keyword search used in the identification process.

Database	Search String
Scopus	TITLE-ABS-KEY ((“colorectal cancer” OR “colorectal neoplasm * 1” OR “colorectal tumor *” OR “colorectal carcinoma” OR “large bowel cancer”) AND (“cluster analysis” OR “spatial analysis” OR “geographical information system” OR “geographic distribution” OR “incidence distribution” OR “demography”)) AND (“risk factor *” OR “cancer risk” OR “determinant *”))
Web of Science	TS = ((“colorectal cancer” OR “colorectal neoplasm *” OR “colorectal tumor *” OR “colorectal carcinoma” OR “large bowel cancer”) AND (“cluster analysis” OR “spatial analysis” OR “geographical information system” OR “geographic distribution” OR “incidence distribution” OR “demography”)) AND (“risk factor *” OR “cancer risk” OR “determinant *”))
PubMed	((“colorectal cancer” OR “colorectal neoplasm *” OR “colorectal tumor *” OR “colorectal carcinoma” OR “large bowel cancer”) AND (“cluster analysis” OR “spatial analysis” OR “geographical information system” OR “geographic distribution” OR “incidence distribution” OR “demography”)) AND (“risk factor *” OR “cancer risk” OR “determinant *”))
EBSCOHost	((“colorectal cancer” OR “colorectal neoplasm *” OR “colorectal tumor *” OR “colorectal carcinoma” OR “large bowel cancer”) AND (“cluster analysis” OR “spatial analysis” OR “geographical information system” OR “geographic distribution” OR “incidence distribution” OR “demography”)) AND (“risk factor *” OR “cancer risk” OR “determinant *”))

¹ The symbol * was used in the search strategy as truncation and wildcard function to increase variability of selected keywords.