CH&E 4010 Lecture Notes - Lecture 16: Genetic Marker, Myocardial Infarction, Confounding

• School: Dalhousie University
• Department: Community Health&Epidemiology
• Course: CH&E 4010
• Professor: Leslie Campbell

Document Summary

Objectives: apply strategies for determining effect of confounding and effect modification. Interpret results of analysis to determine presence of confounding and effect modification. Is associated with both exposure of interest and outcome, but is not on the causal pathway. Is present to a greater or lesser degree in study group vs. comparison group, so distorts the association between the exposure and outcome of interest: positive confounder: effect of confounder overestimates magnitude of association (orcrude > Oradjusted: negative confounder: effect of confounder underestimates magnitude of association (orc < ora) Is a real effect - helps to clarify the relationship between an exposure and outcome in presence of other factors: we report effect modification by reporting stratum-specific effects (ors) we do not hold this constant. Example confounding or effect modification: there is a vaccination campaign in effect in some counties of a state to educate parents about childhood diseases and recommended vaccines for their children.