Ability to trace migrant farmworkers ten years after initial identification in a northern state (Wisconsin)

Background Migrant farmworkers have rarely been included in epidemiologic s tudies. To assess the feasibility of following farmworkers, over extended p eriods, a critical feature of many study designs, we attempted to trace a s ample of Mexican-American farmworkers identified in a clinic in Wisconsin. Methods We randomly chose 100 farmworkers from a migrant health center regi stration list for 1984-85. In 1995, we searched recent clinic records, made telephone calls, and visited migrant camps to find these farmworkers in Wi sconsin during the growing season. We also attempted to find 46 farmworkers at their homes in southwest Texas over a two-week period in 1996 using the address listed in the clinic records, local phone books, and conversations with next-door neighbors. Results Although 25 farmworkers had reregistered at the clinic in recent ye ars, we found only 6 of them in Wisconsin in 1995. In southwest Texas, we e ither located or ascertained information about the vital status of 25 of th e 46 farmworkers (54%). Conclusions Tracing efforts must include extensive contacts in farmworkers home states and must incorporate a variety of information sources. Tracing farmworkers in epidemiologic studies appears to be feasible but requires mo re intensive methods over longer periods of time than those used in this st udy. (C) 2001 Wiley-Liss, Inc.