Using CBPR for participant retention in a prospective study of the neurological effects of occupational pesticide exposure in farmworkers

Community-based participatory research (CBPR) joins communities and researchers to facilitate encouraging community members to participate in research relevant to their health. In prospective epidemiological studies, CBPR designs should aid in participant retention. 371 Latino males (210 exposed migrant farmworkers and 161 non-exposed non-farmworkers) were enrolled in a prospective CBPR study of the neurological effects of occupational pesticide exposure. The sample was constructed via face to face recruitment employing community partners who visited potential participants in their homes. Participants were enrolled at a clinic visit where biological sample collection and neurological testing were conducted. Those who returned for a second clinic three months later were compared to those who did not on age, education, marital status, social integration and participation, CES-D, and exposure status (farmworker vs. non-farmworker). Overall, 68.7% of the 371 participants were retained. The retention rate for farmworkers was 65.7%; the rate for the non-farmworkers was 72.7%. Retained participants differed only on exposure status. The community partners reported that community members discontinued participation due to lack of trust in the study, fear of contributing blood samples, peer influence, seasonal demands of farm work, and loss to follow up due to the transient nature of the population being studied. While stable non-migrant populations will always be easier to retain in prospective studies, retention strategies focused on potentially modifiable barriers such as fear and lack of trust are needed to enhance retention. Community partnerships provide the appropriate context for exploring such barriers and developing effective solutions.