%0 Journal Article
%T Determinants of subject visit participation in a prospective cohort study of HTLV infection
%A Deborah A DeVita
%A Mary C White
%A Xin Zhao
%A Zhanna Kaidarova
%A Edward L Murphy
%J BMC Medical Research Methodology
%D 2009
%I BioMed Central
%R 10.1186/1471-2288-9-19
%X Health questionnaires and physical exams were administered at enrollment and 2-year intervals through 2004. To examine factors influencing attendance at study visits of the cohort participants we calculated odds ratios (ORs) with generalized estimated equations (GEE) to analyze fixed and time-varying predictors of study visit participation.There were significant independent associations between better visit attendance and female gender (OR = 1.31), graduate education (OR = 1.86) and income > $75,000 (OR = 2.68). Participants at two centers (OR = 0.47, 0.67) and of Black race/ethnicity (OR = 0.61) were less likely to continue. Higher subject reimbursement for interview was associated with better visit attendance (OR = 1.84 for $25 vs. $10). None of the health related variables (HTLV status, perceived health status and referral to specialty diagnostic exam for potential adverse health outcomes) significantly affected participation after controlling for demographic variables.Increasing and maintaining participation by minority and lower socioeconomic status participants is an ongoing challenge in the study of chronic disease outcomes. Future studies should include methods to evaluate attrition and retention, in addition to primary study outcomes, including qualitative analysis of reasons for participation or withdrawal.Understanding participation in a prospective study is crucial to maintaining and improving retention rates [1,2]. A high participant loss rate will impact the ability to draw valid conclusions. This is particularly relevant in longitudinal studies where loss of data points within or between visits can distort the relationships between measurements [3,4]. Many strong predictors of attrition, such as health problems and socioeconomic factors [5], race/ethnicity [6], and substance abuse [7] have been explored in efforts to develop strategies to maintain participation in a long term cohort study. Most studies evaluate retention by employing a survival approa
%U http://www.biomedcentral.com/1471-2288/9/19