title: Re-contacting participants for inclusion in the database of Genotypes and Phenotypes (dbGaP): Findings from three case-control studies of lung cancer.
abstract: BACKGROUND
  Since January 2008, the National Institutes of Health (NIH) has required that all investigators who receive NIH support submit de-identified high-throughput genomic data to the database of Genotypes and Phenotypes (dbGaP). The purpose of this study was to explore the feasibility of re-consenting participants from three inactive studies, conducted from 2000 through 2009, to submit their data to dbGaP.
  
  
  METHODS
  Participants were those enrolled in one of three prior population-based case-control studies of lung cancer who had given a DNA sample. Consent to release de-identified data to dbGaP took place via mailed forms and follow-up phone calls. Chi-squared tests were used to examine differences in re-contact and consent proportions between groups.
  
  
  RESULTS
  A total of 2,471 participants were initially eligible for re-contact. Six hundred and thirty-eight participants were found to be deceased (n = 627) or did not give permission to re-contact (n = 11). Of the 1,833 remaining participants, 42.3% provided written consent, 37.0% could not be located, 13.7% verbally agreed to have their data released but never returned written consent, 5.3% refused, and 1.6% were too ill at the time of contact. There were significant differences in ability to locate participants by age, race, gender, and case-control status; however, once located, there were no differences in re-consent rates.
  
  
  CONCLUSIONS
  This study demonstrates that while most previous study participants agreed to release data, a small proportion are opposed to submitting their data to dbGaP. In addition, it demonstrates the difficulty studies based on existing samples may have in locating inactive participants for re-consent.
authors.affiliation: Department of Oncology, Wayne State University School of Medicine, 4100 John R. Mailstop: MM04EP, Detroit, Michigan 48201 USA ; Karmanos Cancer Institute, Population Studies and Disparities Research Program, Detroit, MI USA.
authors.forename: Michele L
authors.initials: ML
authors.lastname: Cote
authors.affiliation: Center for Molecular Medicine and Human Genetics, Wayne State University School of Medicine, Detroit, MI USA.
authors.forename: M Jay
authors.initials: MJ
authors.lastname: Harrison
authors.affiliation: Department of Oncology, Wayne State University School of Medicine, 4100 John R. Mailstop: MM04EP, Detroit, Michigan 48201 USA.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Wenzlaff
authors.affiliation: Department of Oncology, Wayne State University School of Medicine, 4100 John R. Mailstop: MM04EP, Detroit, Michigan 48201 USA ; Karmanos Cancer Institute, Population Studies and Disparities Research Program, Detroit, MI USA.
authors.forename: Ann G
authors.initials: AG
authors.lastname: Schwartz