Disaster victims from ethnic minorities manifest more health complaints and concerns than others following a medical investigation. The authors aimed at analyzing ethnicity as a proxy for risk factors predictive of changes in health-related anxiety, and mediators that explain ethnic group differences after participating in a medical investigation. Western (n = 406) and non-Western participants (n = 379) were assessed at baseline and 12-week follow-up. Education, unemployment, years of residence, and posttraumatic stress disorder symptoms were independent predictors of changes in health-related anxiety, excluding ethnicity. The predictive value of ethnicity was mediated mainly by changes in psychopathology, fatigue, and quality of life. Stronger responses to a trauma-related investigation by more vulnerable ethnic minority groups may explain their enhanced health-related anxiety.