Background: Few studies have addressed retention of minorities, particularly African Americans, in longitudinal research. Our aim was to determine whether there was differential retention between African Americans and Whites in the ARIC cohort and identify cardiovascular disease (CVD) risk factors and indicators of socioeconomic status (SES) associated with these retention differences.
Methods: 15,688 participants, 27% African American and 73% White, were included from baseline, 1987-1989, and classified as having died, lost or withdrew from study contact, or remained active in study calls through 2013. Life tables were created illustrating retention patterns stratified by race, from baseline through visit 5, 2011-2013. Prevalence tables stratified by race, participation status, and center were created to examine CVD risk factors and SES at baseline and visit 5.
Results: 54% of African Americans compared with 62% of Whites were still in follow-up by 2013. This difference was due to an 8% higher cumulative incidence of death among African Americans. Those who remained in follow-up had the lowest baseline CVD risk factors and better SES, followed by those who were lost/withdrew, then those who died. Whites had lower levels of most CVD risk factors and higher SES than African Americans overall at baseline and visit 5; though, the magnitude of visit 5 differences was less.
Conclusions: In the ARIC cohort, retention differed among African Americans and Whites, but related more to mortality differences than dropping-out. Additional research is needed to better characterize the factors contributing to minority participants' recruitment and retention in longitudinal research.
Keywords: Attrition; CVD Risk Factors; Prospective Cohort; Race; SES.