A Japanese five-constitution model: validation and characterization using the constitution in Chinese medicine questionnaire – Japanese version

S. Yokoyama, H. Arie, Y. Nakamura, N. Murayama, K. Murashita, T. Mikami, N. Suzuki, S. Kanaya

Innovation Center for Health Promotion, Hirosaki University Graduate School of Medicine, Aomori, Japan. shintaro-y@hirosaki-u.ac.jp

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• Alternative medicine

OBJECTIVE: The 60-item Constitution in Chinese Medicine Questionnaire (CCMQ), based on a traditional nine-constitution framework, has been widely used in China for health assessments. However, its length poses a practical barrier to its widespread clinical use. A previous study in Japan suggested that a five-constitution model was more optimal for the Japanese population and subsequently developed a simplified 18-item questionnaire. This study aimed to validate the structure of this five-constitution model and establish the standalone diagnostic accuracy of the 18-item questionnaire.

MATERIALS AND METHODS: This was a secondary analysis of a cross-sectional dataset comprising 851 healthy Japanese participants who completed the 60-item CCMQ. We first used hierarchical clustering (the NbClust package) on the 18-item data to determine the optimal number of clusters. We then used principal component analysis (PCA) to analyze the structure of the clusters. Finally, a decision-tree model was developed to classify participants based on the 18 items, and its performance was evaluated using 10-fold cross-validation.

RESULTS: Clustering analysis of the 18-item data confirmed that five was the optimal number of clusters. PCA revealed that the five groups were clearly separated along a primary “health axis”. The decision-tree model, using only 18 items, successfully classified participants into five constitution types (a structure validated on the 18-item data itself), with an overall accuracy of 81.6% and a balanced accuracy of 81.3%.

CONCLUSIONS: The 18-item simplified questionnaire is a valid and reliable instrument for constitutional assessment in Japan. This concise tool effectively retains the structural and predictive information of the original 60-item version, offering a practical solution for large-scale research and personalized health management in clinical settings.

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