Participation in pediatric epidemiologic research: the SEARCH for Diabetes in Youth Study experience.

BACKGROUND

We evaluated the association of demographic and clinical characteristics with participation in an epidemiologic study of diabetes mellitus among youth.

METHODS

SEARCH for Diabetes in Youth is a multicenter study of physician-diagnosed diabetes in youth under the age of 20 comprising a surveillance and a cohort component. At each center, we enumerated all prevalent cases of diabetes in 2001 (n=6266) and all incident cases between 2002 and 2004 (n=3668). After confirmation of eligibility and validation, we invited each case to complete a survey and participate in a study visit. Here we evaluate how age, sex, race, and diabetes type are associated with participation in the survey and study visit.

RESULTS

Among prevalent cases, participation in the survey was 68% and 41% in the study visit. Among 2002 to 2004 incident cases, participation varied for the survey (76%, 81%, and 82%) and study visit (52%, 60%, and 60%). In multivariate logistic regression analyses among all incident cases, older age was associated with a lower odds of participation in the study visit (15-17 vs. <10 years: OR 0.5, 95% CI 0.4-0.7; 18-19 vs. <10 years: OR 0.3, 95% CI 0.2-0.5), as was having type 2 diabetes vs. type 1 diabetes (OR 0.5, 95% CI 0.4-0.7) and being of African American race vs. non-Hispanic White (OR 0.6, 95% CI 0.4-0.8). Results were very similar among prevalent cases.

CONCLUSIONS

Elucidating the relationship between individual characteristics and participation is essential for evaluating nonresponse bias, correcting for it, and for planning and implementing recruitment strategies.