title: Alternative recruitment strategies influence saliva sample return rates in community-based genetic association studies.
abstract: Collection of saliva for DNA extraction has created new opportunities to recruit participants from the community for genetic association studies. However, sample return rates are variable. No prior study has specifically addressed how study design impacts sample return. Using data from three large-scale genetic association studies we compared recruitment strategy and sample return rates. We found highly significant differences in sample return rates between the studies. In studies that recruited retrospectively, overall returns were much lower from families with a self-limiting condition who provided samples at a research centre or home visit, than adult elderly individuals with a chronic disease who provided samples by post (59% vs. 84%). Prospective recruitment was associated with high agreement to participate (72%), but subsequent low return of actual saliva samples (42%). A telephone call had marginal effect on recruitment in a retrospective family study, but significantly improved returns in a prospective family study. We found no effect upon DNA yield comparing observed versus unobserved sample collection, or between male and female adult participants. Overall, study design significantly impacts upon response rates for genetic association studies recruiting from the community. Our findings will help researchers in constructing and costing a recruitment protocol.
authors: Nuffield Department of Surgical Sciences, University of Oxford, Level 6, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, UK. m.bhutta@doctors.org.uk
authors: Mahmood F
authors: MF
authors: Bhutta
authors: Lindsey
authors: L
authors: Hobson
authors: Jane
authors: J
authors: Lambie
authors: Elizabeth S H
authors: ES
authors: Scaman
authors: Martin J
authors: MJ
authors: Burton
authors: Henk
authors: H
authors: Giele
authors: Sarra E
authors: SE
authors: Jamieson
authors: Dominic
authors: D
authors: Furniss
mesh_terms: D005191:Family Characteristics; D056726:Genetic Association Studies; D005828:Genetics, Population / Q000379:methods; D015277:Hotlines / Q000706:statistics & numerical data; D006801:Humans; D010358:Patient Participation / Q000706:statistics & numerical data*; D018579:Patient Selection; D011446:Prospective Studies; D012189:Retrospective Studies; D012463:Saliva / Q000166:cytology*; D013048:Specimen Handling / Q000379:methods / Q000706:statistics & numerical data*