Question: Dr. Kim wanted to assess the evidence regarding whether the bacteria Helicobacter pylori (H. pylori) was a causal factor for duodenal ulcers, considering Hill's Causal Critiera. He used the following data in his assessment. Please indicate which causal criteria the data best correspond to: 1) In a study of 454 patients who were initially free of duodenal ulcer and who underwent endoscopy, 34 of 321 who were positive for H. pylori at endoscopy, had developed duodenal ulcer 10 years later (11%), compared to only 1 of 133 patients who were negative for H. pylori (0.8%)