Measuring body constitution: validation of the Body Constitution Questionnaire (BCQ) in Hong Kong.

The Body Constitution Questionnaire (BCQ) was developed in Taiwan to classify people into body constitution (BC) types based on Traditional Chinese Medicine (TCM) theories. Since the culture of Hong Kong is different from Taiwan, the BCQ must be validated before a wider application can be preceded.To adapt and validate the Hong Kong version of BCQ in Hong Kong Chinese population.The content validity of BCQ was investigated by the cognitive debriefing with 10 patients and 10 Chinese Medicine Practitioners (CMP). A cross-sectional study of 1084 Chinese patients recruited from TCM and Western Medicine (WM) outpatient clinics to confirm the construct validity, reliability, sensitivity and responsiveness of BCQ. 225 of the patients were assessed after 2 weeks for the test-retest reliability. 404 subjects were followed up to evaluate the responsiveness after 3-6 months.Cognitive debriefing confirmed the content validity of the BCQ (HK version) with content validity index of all items ranged from 70 to 100%. 1084 out of 2128 patients (51%) completed the cross-sectional study. The construct validity was confirmed with scaling success rates that ranged from 87.5 to 89.5%, moderate correlations between with SF-12v2 scores, and 3-factors structure with confirmatory factor analysis. The reliability was confirmed by the Cronbach's alphas >0.8 and test-retest reliability (intra-class correlation coefficients >0.8).BCQ was adapted and validated on Hong Kong Chinese population. Patients with imbalanced BC types had lower health-related quality of life (HRQOL) than those with balanced BC types, which supported the validity and importance of the body constitution under the concept of TCM.