title: The impact of population-based screening studies on hemochromatosis screening practices.
abstract: OBJECTIVE
  To determine if community population screening studies for hemochromatosis affected HFE genetic screening practices in non-study populations.
  
  
  METHODS
  An audit of all genetic testing for HFE mutations at London Health Sciences Center, London, Ontario, Canada from 1997 to 2010 was performed. The frequency of genetic testing and the frequency of C282Y homozygous cases identified during the years of the London Red Cross (1998-1999) and HEIRS (2000-2005) screening studies were compared with the corresponding frequencies in the specified years outside this range (1997-1998 and 2006-2010).
  
  
  RESULTS
  An increase in HFE gene mutation testing is seen during the London Red Cross study, and the frequency of testing rose further during the HEIRS study. Genetic screening activity continued to increase in the years after publication of the HEIRS study. The proportion of patients with homozygosity for C282Y mutation remained relatively constant despite fluctuations in numbers of persons screened per annum.
  
  
  CONCLUSIONS
  The rise in HFE gene testing among non-study populations during the HH studies could be explained by the Hawthorne effect, a phenomenon referring to the improvement or modification of behavior by a population as a consequence of it being studied. In this case, we postulate that primary care physicians at our center performed more HFE gene tests for their patients as a consequence of being affected by knowledge of the screening studies. Despite a general increase in testing during and after completion of the studies, the total number of hemochromatosis cases (C282Y homozygotes) diagnosed per annum remained relatively constant.
authors.affiliation: Department of Medicine, University Hospital, University of Western Ontario, 339 Windermere Rd, London, ON N6A 5A5, Canada. chandok.n@gmail.com
authors.forename: Natasha
authors.initials: N
authors.lastname: Chandok
authors.forename: Mark
authors.initials: M
authors.lastname: Speechley
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ainsworth
authors.forename: Subrata
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Paul C
authors.initials: PC
authors.lastname: Adams
mesh_terms: D015987:Effect Modifier, Epidemiologic; D056726:Genetic Association Studies; D005817:Genetic Counseling / Q000458:organization & administration*; D005820:Genetic Testing / Q000379:methods*; D006432:Hemochromatosis / Q000453:epidemiology / Q000235:genetics; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008131:London; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D009864:Ontario
chemical_list: C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins