Factors affecting retention of adult Mexican-American participants in a longitudinal population-based study

This study elucidated effective strategies for the retention of healthy Mexican American participants and filled a gap in the literature identifying particular characteristics of participants who failed to comply with follow-up contacts in an on-going population-based longitudinal study. A total of 4142 Mexican American adults (18-91 years) participants residing in Harris County between July 2001 and October 2004 were recruited. During 63 months of follow-up, eight sequential follow-up schemes were conducted at different times and with different population samples. An average response rate of 76.5% was achieved with 33.5 % of responses received by mail and 66.5% completed by telephone. The following outcomes were gathered after 5 telephone calls were attempted, on average, with each non-respondent: telephone numbers were disconnected (31%), participants had relocated/moved without a follow-up address (27.5%), participants were deceased (1%), participants refused to continue participating in the study (1.5%), participants were unable to be contacted (39%). Multiple logistic regression results suggested that: being a male (ORadj = 0.56), of young age (ORadj = 1.04), not being married (ORadj = 0.64), with low index of acculturation to English language (ORadj = 0.68), not owning a home (ORadj = 0.39%), and being a current smoker (ORadj = 0.57) are all covariates statistically associated with not returning at least one follow-up contact (p < 0.05). Covariates were adjusted for the different number of waves of follow up in which each participant was included. Several strategies are recommended for researchers attempting the recruitment and retention of healthy Mexican Americans adult populations