title: A comparison of participants and non-participants in the Chennai Glaucoma Study-rural population.
abstract: OBJECTIVE
  To study whether the difference in the demographic characteristics of participants and non participants could result in biased prevalence estimates and associations.
  
  
  OBJECTIVE
  To compare the non-participant and participant characteristics, and to ascertain if non-response bias is present in the rural population of the Chennai Glaucoma Study (CGS).
  
  
  METHODS
  Rural participants and non-participants were compared with regard to socio-demographic variables (age, gender, religion, mother tongue, literacy and employment).
  
  
  RESULTS
  4800 subjects aged 40 years or over were enumerated, 82% (3934: 45% male and 55% female) responded. Gender did not influence participation (adjusted OR-1.11, CI: .91-1.36). Subjects in the 70-79 year age group were more likely to respond (OR-1.76; CI-1.31-2.38). Hindus had a higher participation rate than Christians or Muslims (adjusted OR-2.63, CI: 1.80-3.84). The other predictors of participation were illiteracy (adjusted OR-1.44, CI: 1.22-1.70), unemployment (OR-1.28, CI: 1.04-1.58), place of residence (main villages) (OR-6.66, 95% CI: 4.6-9.64).
  
  
  CONCLUSIONS
  Based on our study findings, it does not seem likely that participation bias will affect the study results.
authors: Glaucoma Projectm, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India.
authors: Pradeep P
authors: PP
authors: Paul
authors: Ronnie J
authors: RJ
authors: George
authors: Hemamalina
authors: H
authors: Arvind
authors: Madan
authors: M
authors: Raj
authors: Augustian
authors: S Ve
authors: SV
authors: Ramesh
authors: Prema
authors: P
authors: Sriram
authors: Govindasamy
authors: G
authors: Kumaramanickavel
authors: Catherine
authors: C
authors: McCarthy
authors: Lingam
authors: L
authors: Vijaya
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D005260:Female; D005901:Glaucoma / Q000453:epidemiology*; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010358:Patient Participation / Q000706:statistics & numerical data*; D015995:Prevalence; D045808:Refusal to Participate / Q000706:statistics & numerical data*; D012067:Religion; D012424:Rural Population / Q000706:statistics & numerical data*; D017678:Sex Distribution