title: Stepping towards causation in studies of neighborhood and environmental effects: how twin research can overcome problems of selection and reverse causation.
abstract: No causal evidence is available to translate associations between neighborhood characteristics and health outcomes into beneficial changes to built environments. Observed associations may be causal or result from uncontrolled confounds related to family upbringing. Twin designs can help neighborhood effects studies overcome selection and reverse causation problems in specifying causal mechanisms. Beyond quantifying genetic effects (i.e., heritability coefficients), we provide examples of innovative measures and analytic methods that use twins as quasi-experimental controls for confounding by environmental effects. We conclude that collaboration among investigators from multiple fields can move the field forward by designing studies that step toward causation.
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, WA 98195, USA; Interdisciplinary Graduate Program in Nutritional Sciences, University of Washington, Seattle, WA 98195, USA. Electronic address: duncag@u.washington.edu.
authors.forename: Glen E
authors.initials: GE
authors.lastname: Duncan
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Brianna
authors.initials: B
authors.lastname: Mills
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Strachan
authors.affiliation: Department of Urban Design and Planning, Urban Form Lab, University of Washington, Seattle, WA 98195, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Hurvitz
authors.affiliation: Interdisciplinary PhD Program in Urban Design and Planning, Urban Form Lab, University of Washington, Seattle, WA 98195, USA.
authors.forename: Ruizhu
authors.initials: R
authors.lastname: Huang
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, WA 98195, USA; Department of Urban Design and Planning, Urban Form Lab, University of Washington, Seattle, WA 98195, USA.
authors.forename: Anne Vernez
authors.initials: AV
authors.lastname: Moudon
authors.affiliation: Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Turkheimer
mesh_terms: D015984:Causality; D004779:Environment Design / Q000706:statistics & numerical data*; D006801:Humans; D008962:Models, Theoretical; D018579:Patient Selection; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D040242:Risk Reduction Behavior; D018433:Twin Studies as Topic
keywords: Causality; Environment design; Lifestyle risk reduction; Social and built environments; Twin studies