In a study of a disease in which all cases that developed were ascertained, if the relative risk for the association between a f
actor and the disease is equal to or less than 1.0, then:a. There is no association between the factor and the diseaseb. The factor protects against development of the diseasec. Either matching or randomization has been unsuccessfuld. The comparison group used was unsuitable, and a valid comparison is not possiblee. There is either no association or a negative association between the factor and the disease
The correct option is E: There is either no association or a negative association between the factor and the disease
Explanation:
Relative risk is a ratio that compares the risk of a health event between two groups. When the relative risk is 1, this means that the risk among the two groups are identical. When the relative risk is more than one, this means there is an increased risk for the exposed group. A risk ratio of less than 1, means that there is decreased exposure, which means negative association, which implies that exposure protect against the disease. Hence from the question, a value of relative risk less than or equal to one signifies no association or negative association.
