In a coho study, to study association between factor and disease, the risk ratio was calculated to be equal to 1. What does this signifies?
(A) There is no association present between the factor and the disease (B) There is positive association between the factor and the disease (C) There is negative association between the factor and the disease (D) Data insufficient to comment
(A) Ans: A. There is no association present between the factor and the diseaseEstimation of relative risk (RR):Direct measure (or index) of strength of association between suspected cause and effect.RR=1 - Indicates no association.RR > 1 - Indicates positive association between exposure & disease under study.RR = 2 - Indicates incidence rate of disease is 2 times higher in exposed group (compared with unexposed).Impoant in etiological enquiries.