Can We Determine Sasang Constitutional Body Type Merely by Facial Inspection?

Objectives: This study aimed to assess the inter-observer concordance rate of anthroscopic examination on facial features among experts in Sasang constitutional medicine (SCM) in order to evaluate the presence of statistical differences in facial structural characteristics among different body types of Sasang constitution (SC), and to develop an objective method for facial analysis for diagnosing SC types to prevent SCM experts from misdiagnosis by their perceptional errors about faces. Methods: This was a double-blinded cross-sectional study conducted on 174 people's faces. Ten SCM experts participated in this study. Frontal and lateral photographs of subjects were standardized and displayed to 10 SCM experts for diagnosing the SC type by anthroscopic examination alone (experiment 1). The subjects' faces were analyzed by photogrammetric method to investigate the presence of any typical structural characteristics of the faces to differentiate SC type (experiment 2). Comparing subjects' SC type with anthroscopic diagnosis by 10 SCM experts, the inter-observer concordance rates were measured (experiment 1). Using photogrammetric facial analysis, a multinomial logistic model was made for analyzing the correlation of SC type and subjects' facial structural configuration (experiment 2). Results: The inter-observer concordance rate of anthroscopic examination was 2.9% in experiment 1. Using a multinomial logistic fitting model, the predicted probability for determining SC type was 52.8-57.6% in experiment 2 (p < 0.05). Prototype composite faces were also created from photographs of subjects who received the same SC type from the SCM experts. Conclusions: As SC type cannot be precisely diagnosed using anthroscopic examination alone, SCM needs a definitive objective and scientific diagnosing method to be a scientifically verified alternative medicine and be globalized in future.