title: The Breakthrough Generations Study: design of a long-term UK cohort study to investigate breast cancer aetiology.
abstract: BACKGROUND
  The rationale, design, recruitment and follow-up methods are described for the Breakthrough Generations Study, a UK cohort study started in 2003, targeted at investigation of breast cancer aetiology.
  
  
  METHODS
  Cohort members have been recruited by a participant referral method intended to assemble economically a large general population cohort from whom detailed questionnaire information and blood samples can be obtained repeatedly over decades, with high completeness of follow-up and inclusion of large numbers of related individuals. 'First-generation' recruits were women contacted directly, or who volunteered directly, to join the study. They nominated female friends and family, whom we contacted, and those who joined ('second generation') nominated others, reiterated for up to 28 generations.
  
  
  RESULTS
  The method has successfully been used during 2003-2011 to recruit 112,049 motivated participants with a broad geographic and socioeconomic distribution, aged 16-102 years, who have completed detailed questionnaires; 92% of the participants gave blood samples at recruitment. When eligible, 2½ years after recruitment, >98% completed the first follow-up questionnaire. Thirty percent are first-degree relatives of other study members.
  
  
  CONCLUSIONS
  The 'generational' recruitment method has enabled recruitment of a large cohort who appear to have the commitment to enable long-term continuing data and sample collection, to investigate the effects of changing endogenous and exogenous factors on cancer risk.
authors: Section of Epidemiology, Institute of Cancer Research, Sir Richard Doll Building, 15 Cotswold Road, Sutton, Surrey SM2 5NG, UK. anthony.swerdlow@icr.ac.uk
authors: A J
authors: AJ
authors: Swerdlow
authors: M E
authors: ME
authors: Jones
authors: M J
authors: MJ
authors: Schoemaker
authors: J
authors: J
authors: Hemming
authors: D
authors: D
authors: Thomas
authors: J
authors: J
authors: Williamson
authors: A
authors: A
authors: Ashworth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016901:Intergenerational Relations; D008875:Middle Aged; D018579:Patient Selection; D011379:Prognosis; D011446:Prospective Studies; D012107:Research Design; D012307:Risk Factors; D011795:Surveys and Questionnaires; D006113:United Kingdom; D055815:Young Adult