Published in:
01-03-2021 | Polycystic Ovary Syndrome | COMMENTARY
Are Mendelian randomization investigations immune from bias due to reverse causation?
Authors:
Stephen Burgess, Sonja A Swanson, Jeremy A Labrecque
Published in:
European Journal of Epidemiology
|
Issue 3/2021
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Excerpt
Mendelian randomization uses genetic variants as instrumental variables to make causal inferences about the effect of a risk factor on an outcome [
1,
2]. If a genetic variant satisfies the instrumental variable assumptions for the given risk factor and outcome [
3], then an association between the genetic variant and the outcome implies the risk factor affects the outcome in some individuals at some point in the life-course [
4]. Combining the instrumental variable assumptions with further assumptions and precise specification of the outcome (including specifying a time period for the outcome) allows valid testing of a more specific causal hypothesis and/or valid estimation of global or local, and point or period average causal effects [
5]. …