The relative risk of 1 indicates that
Relative risk is the ratio of the incidence of the disease (or death) among exposed and the incidence among non-exposed. A relative risk of 1 means the incidence in exposed and non-exposed is same. So there is no relation between disease and cause (exposure). Park, pg: 79
There is no cause effect relationship
Effect may be due to type 1 error
Strong correlation
Effect may be due to type 2 error
Epidemiology