Table 4.

Results of multivariate analysis for colon cancer

factors	OR	95%CI	P
drining mixed source water (y = 1, n = 0)	2.387		1.243	4.587	0.009
mucous blood history (y = 1, n = 0)	3.508	1.370	8.985	0.009

Table 4 and Table 5 illustrated that, at P = 0.05 level, both for colon cancer and rectal cancer, the final logistic regression model comprised two factors: mixed water source drinking and mucous blood stool history.