Validation of the translation and cross-cultural adaptation into Finnish of the Abdominal Symptom Questionnaire, the Hospital Anxiety and Depression Scale and the Complaint Score Questionnaire

Background: Epidemiological surveys require questionnaires to be validated in the native language of the participants. The aim of this study was to validate the Finnish translations of the Abdominal Symptom Questionnaire (ASQ), the Hospital Anxiety and Depression Scale ( HAD) and the Complaint Score Questionnaire (CSQ). Methods: A random sample of adults (n = 3000) in a northern Swedish bilingual district was surveyed using a mailed ASQ offered in both Swedish and Finnish, and 2122 responded ( 239 in Finnish). A random subsample of the responders ( n = 1001, 123 preferring Finish) was then surveyed once more using the ASQ, the HAD and the CSQ. The first 50 responders of the latter survey were then given the three questionnaires again within two weeks. The Finnish versions had been put through a comprehensive translation procedure Results: A factor analysis comparison between the responders using either language in the mailed survey gave a comparable factor construction, and this was also comparable with an earlier analysis of the Swedish version. The Finnish responses to the second survey were further evaluated by testing internal consistency reliability, convergent validity towards previously validated relevant instruments (ShortForm-36 and the Gastrointestinal Symptom Rating Scale) and the test/re-test accuracy of the three questionnaires. These were found to be reliable, as was the correlation between the ASQ and the CSQ, for relevant domains. Conclusion: The Finnish translations of the ASQ, HAD and CSQ questionnaires all seem to be robust and usable for population-based surveys among Finnish adults.