USE OF MEDICATION DATA TO VALIDATE AN ASSOCIATION IN COMMUNITY-BASED SYMPTOM PREVALENCE STUDIES

A chemical spill from an oil refinery in Texas City, Texas, exposed th e community to more than 40 000 Ibs (18 144 kg) of highly toxic and co rrosive hydrofluoric acid. A symptom prevalence study indicated an ass ociation between symptom reports, most notably breathing symptoms, and hydrofluoric acid exposure. Although verification of self-reported sy mptoms by checking medical records or performing clinical tests is the oretically possible, it is not a feasible alternative in dealing with an entire community. Open-ended data on medication use collected in th e prevalence study were coded by organ system and analyzed by cross-cl assification techniques and log linear models. Results showed that the reported use of medication for hydrofluoric acid-related problems was associated with the exposure; medication use for problems unrelated t o hydrofluoric acid exposure was uniform across the exposure categorie s. Moreover, medication use was significantly associated with the seve rity of breathing-related problems for each exposure category. Medicat ion use, however, may have been under-reported because it seems diffic ult to conjure up the names of medications that were not taken or medi cations not taken recently may not be recalled. Nonetheless, open-ende d medication data may be a useful surrogate approach to validating an association between an exposure and health outcomes.