The Tachikawa cohort of motor vehicle accident study investigating psychological distress: Design, methods and cohort profiles

Background: The Tachikawa cohort of motor vehicle accident (TCOM) Study has been carried out in Tokyo since 2004. This study examined the association of medical and psychosocial variables evaluated shortly after admission to the acute critical care center with long-term psychiatric morbidity risk in patients with accidental injuries. Methods: Between May 2004 and January 2008, patients with accidental injury consecutively admitted were recruited to the TCOM Study. Psychiatric morbidity as a primary endpoint was measured using a structured clinical interview at 1, 6, 18 and 36 months after involvement in a motor vehicle accident (MVA). The baseline investigation consisted of self-administered questionnaires concerning acute psychological responses and personality. Medical information was obtained from patients' medical charts. Various socio-demographic data, health-related habits and psychosocial factors were assessed by interview. To examine potential biomarkers of psychological distress, blood samples were collected. Results: Out of 344 patients who were asked to participate in this study, 300 (87%) patients with MVA-related injury were enrolled. Corresponding rates for the questionnaires on psychological responses and blood sampling were 98-99 and 79%, respectively. The cohort sample was composed of 78% men; the median age was 34 years; and 45% of the participants were motorcycle drivers. Conclusions: The TCOM Study should prove useful for researchers examining the association between bio-psychosocial variables and psychological distress and may contribute to the formation of a framework for providing care for patients with MVA-related injury.