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Recruitment and Consent in an observational study
M Goodwin1, W Whittaker2, T Walsh1
1University of Manchester, School of Dentistry, UK.
Objective:
The study sought to explore the consent rate and associated potential bias across a cohort in a large longitudinal population based study.
Research Design:
Data were taken from a study designed to examine the effects of the reintroduction of community water fluoridation on children's oral health over a five-year period. Children were recruited from a fluoridated and non-fluoridated area in Cumbria, referred to as Group 1 and Group 2.
Results:
Data were available for 3138 individuals. The consent rate was 12.91 percentage points lower in Group 2 than Group 1 (95% CI -16.27 to -9.56, p⟨0.001). The population in Group 2 was more deprived (higher Index of Multiple Deprivation (IMD)) than Group 1 before consent was taken. Consent was not associated with deprivation in either group.
Conclusion:
The cohort appeared to be unaffected by IMD-related non-consent. However there was a difference in consent rate between the two groups. With the population in Group 1 being more deprived than Group 2, it will be important to incorporate these differences into the analysis at the end of this longitudinal study.
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