This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': "The measure of strength of association between risk factor and outcome is: \nSelect and explain. \nA. Odds ratio, B. Attributable risk, C. Relative risk, D. Poisson's ratio", 'role': 'user'}, {'content': 'Answer: A \nExplanation: It is a measure of the strength of association between risk factor and outcome.\nThe derivation of the Odds ratio is based on three assumptions:\xa0\n\ta) The disease being investigated must be relatively rare. In fact, the majority of chronic\xa0diseases have a low incidence in the general population.\n\tb) The cases must be representative of those with the disease.\xa0\n\tc) The controls must be representative of those without the disease.\nFor example, the odds ratio is estimated at 8.1. This implies that the risk of oral cancer was 8.1 times greater in individuals who chewed tobacco than in those who did not chew tobacco.\n\nSoben Peter\xa0\nEssentials of preventive and community dentistry\xa0\n4th edition', 'role': 'assistant'}]