1. Researchers were interested in looking at the relationship between eating bananas (more than 2 a day, 2 or less a day) and constipation (yes/no). They found a crude odds ratio of 2.44 Concemed that vegetarianism might be a confounder or effect modifier, they stratified the group by whether or not the participants were vegetarians. In the vegetarian group, the odds ratio was 3.62 and in the non- vegetarian group, the OR was 1.47. Was vegetarianism a confounder, an effect modifier or neither? How do you know? How would you report this relationship? 2. Researchers were looking at stress during final exams so they conducted a cohort study looking at the number of final exams (4 or more is high, less than 4 is low) and level of stress (high or low). They found a crude relative risk of 10.87. Concerned that major might be a confounder or effect modifier they divided all participants into STEM majors and other majors. The RR for STEM majors was 8.24 and the RR for all other majors was 8.24. Was major a confounder an effect modifier or neither? How do you know? How would you report this relationship? 3. Researchers were assessing the relationship between stress and sleep. A case control study was conducted dividing participants into groups based on whether or not they had insomnia 3 or more times a week or less than three times. Their stress levels were then assessed (high/low). The crude odds ratio was 5.69. Concerned that caffeine intake might be a confounder or an effect modifier of this relationship: participants were stratified into groups - those who drank caffeine containing drinks and those that did not. The OR for the caffeine-drinking group was 5.68 and the OR for the non- caffeine drinking group was 5.67. Was caffeine a confounder, an effect modifier or neither? How do you know? How would you report this relationship?
There were 1322 with blood pressure greater than 120/80. In this group, there were 38 people with CHD and 1284 without CHD. In the CHD group, 13 had diabetes. In the no CHD group. 93 had diabetes. Complete the table below The remaining study participants had normal blood pressure. In this group, there were 82 people with CHD, and the rest did not have CHD. In the CHD group, 70 participants did not have diabetes. In the no CHD group, 77 participants did have diabetes. Complete the table below. 4. Please calculate the appropriate measure of association for the two groups. 5. Based on your analysis of the data, is hypertension an effect modifier, a confounder or neither in this study? How do you know? 6. State how you would report your results.
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