title: Modelling decisions to undergo genetic testing for susceptibility to common health conditions: an ancillary study of the Multiplex Initiative.
abstract: New genetic tests reveal risks for multiple conditions simultaneously, although little is understood about the psychological factors that affect testing uptake. We assessed a conceptual model called the multiplex genetic testing model (MGTM) using structural equation modelling. The MGTM delineates worry, perceived severity, perceived risk, response efficacy and attitudes towards testing as predictors of intentions and behaviour. Participants were 270 healthy insured adults aged 25-40 from the Multiplex Initiative conducted within a health care system in Detroit, MI, USA. Participants were offered a genetic test that assessed risk for eight common health conditions. Confirmatory factor analysis revealed that worry, perceived risk and severity clustered into two disease domains: cancer or metabolic conditions. Only perceived severity of metabolic conditions was correlated with general response efficacy (β = 0.13, p<0.05), which predicted general attitudes towards testing (β = 0.24, p<0.01). Consistent with our hypothesised model, attitudes towards testing were the strongest predictors of intentions to undergo testing (β = 0.49, p<0.01), which in turn predicted testing uptake (OR 17.7, β = 0.97, p<0.01). The MGTM explained a striking 48% of the variance in intentions and 94% of the variation in uptake. These findings support use of the MGTM to explain psychological predictors of testing for multiple health conditions.
authors.affiliation: Department of Nursing and Health Studies, University of Washington Bothell, Bothell, WA, USA. cwade@uwb.edu
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Wade
authors.forename: Shoshana
authors.initials: S
authors.lastname: Shiloh
authors.forename: Samuel W
authors.initials: SW
authors.lastname: Woolford
authors.forename: J Scott
authors.initials: JS
authors.lastname: Roberts
authors.forename: Sharon Hensley
authors.initials: SH
authors.lastname: Alford
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Marteau
authors.forename: Barbara B
authors.initials: BB
authors.lastname: Biesecker
mesh_terms: D000328:Adult; D001007:Anxiety / Q000523:psychology; D003661:Decision Support Techniques; D005260:Female; D020022:Genetic Predisposition to Disease / Q000523:psychology*; D005820:Genetic Testing; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008659:Metabolic Diseases / Q000235:genetics / Q000523:psychology; D060885:Multiplex Polymerase Chain Reaction; D009369:Neoplasms / Q000235:genetics / Q000523:psychology; D010342:Patient Acceptance of Health Care / Q000523:psychology