Table 7. Significant environmental risk factors for duodenal ulcer in residents of Ardabil province; results of final step of multivariable logistic regression analysis.

Risk Factor		OR (95 % CI)	p -value
H.pylori infection	positive vs. negative	5.6 (1.9 – 8.8)	0.001
Smoking	Current vs. non	2.3 (1.4 – 6.5)	0.026
Gender	Men vs. women	3.6 (1.2 – 5.8)	0.008
Residence	Urban vs. Rural areas	1.9 (1.1 – 5.2)	0.039

Nagelkerke R Square = 0.637, method: Stepwise (Backward likelihood)