title: Bounds on natural direct effects in the presence of confounded intermediate variables.
abstract: In epidemiological studies we often want to learn about the direct effect of an exposure on an outcome, i.e. the effect that is not relayed by a specific intermediate variable. In the literature, there are two common definitions of direct effects; controlled and natural. When the intermediate variable and the outcome have common causes, neither the controlled nor the natural direct effect is identified. Cai et al. (Biometrics 2007; 64(3):695-701) derived bounds for the controlled direct effect under a set of hierarchical assumptions. In this paper we derive bounds on the natural direct effect under the same assumptions.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm Nobels väg 12, 171 77 Stockholm, Sweden. arvid.sjolander@ki.se
authors.forename: Arvid
authors.initials: A
authors.lastname: Sjölander
mesh_terms: D000924:Anticholesteremic Agents / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000188:drug therapy / Q000209:etiology; D015984:Causality; D002784:Cholesterol / Q000032:analysis; D002792:Cholestyramine Resin / Q000627:therapeutic use; D016001:Confidence Intervals; D015986:Confounding Factors, Epidemiologic; D015987:Effect Modifier, Epidemiologic; D006801:Humans; D006949:Hyperlipidemias / Q000209:etiology; D011382:Programming, Linear; D011897:Random Allocation; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
chemical_list: D000924:Anticholesteremic Agents; D002792:Cholestyramine Resin; D002784:Cholesterol