Progress in the study of -deficiency constitution in terms of Traditional Chinese Medicine: a narrative review.

The -deficiency constitution has been a hot topic of interest in recent years. Important research progress has been made in quantitative diagnostic criteria and auxiliary identification technologies, modern biological inter-pretations of the constitution characteristics, the association between the -deficiency constitution and diseases, as well as the mechanisms of regulating the constitution. Yet, there are still some deficiencies and limitations. Herein, we systematically reviewed the research progress on the -deficiency constitution by searching articles published in China National Knowledge Infrastructure Database, China Science and Technology Journal Database, Wanfang Database, PubMed, and Embase. The future development direction of the -deficiency constitution should focus on developing objective constitution identification techniques, establishing animal models of -deficiency constitution, conducting constitutional and disease-related research with a high level of evidence, combined with research on the full chain of the nine constitutions so as to obtain more scientific and objective conclusions.