A study found Odd's ratio of maternal hypeension to have IUGR fetus to be 1:5. What is the interpretation drawn ?
Framework of a case control study (The 2 x 2 contigency table) Suspected or risk factors Cases (Disease present) Control (Disease absent) Present Absent a c b d a+c b+d Odds Ratio used to calculate strength of association between risk factor and outcome in case of case control studies. Odds Ratio (OR) = (a x d)/(b x c) Interpretation: OR >1 --> Positive association OR =1 --> No association OR <1 --> Negative/inverse association In this question, OR is 1:5, i.e, 1/5 = 0.2 hence inverse association.
Positive association
Common association
Inverse association
Rare outcome
Epidemiology