ECW and trunk reactance are two core BIA indices independently associated with the dampness constitution, suggesting trunk fluid retention and altered bioelectrical properties in affected individuals.
Key Findings
Results
Extracellular water (ECW) was independently and positively associated with the dampness constitution in multivariable logistic regression.
OR = 1.307, 95% CI: 1.046–1.649, p = 0.021
232 participants were included: 129 with Harmonious constitution and 103 with dampness constitution
Study was cross-sectional, with participants consecutively recruited from a community-based health screening program
Association remained stable across all sensitivity analyses including Winsorization and additional adjustment for waist-to-hip ratio or abdominal circumference
Results
Trunk reactance (Reactance_TR) was independently and positively associated with the dampness constitution in multivariable logistic regression.
OR = 2.163, 95% CI: 1.124–4.267, p = 0.023
Trunk reactance was one of five core features identified by LASSO regression
Association remained stable in all sensitivity analyses
The finding suggests altered bioelectrical properties of trunk tissue in individuals with dampness constitution
Results
LASSO regression identified five core BIA features associated with dampness constitution.
The five features identified were: left lower limb phase angle (PA_LL), trunk reactance (Reactance_TR), extracellular water (ECW), body fat percentage (PBF), and mean grip strength
Least Absolute Shrinkage and Selection Operator (LASSO) regression was used for feature selection
Whole-body and segmental fluid distribution, bioelectrical parameters, and grip strength were all measured as candidate variables
Of the five features, only ECW and Reactance_TR remained independently significant in the multivariable model
Results
In sex-stratified analyses, associations of ECW and trunk reactance with dampness constitution were statistically significant in men but not in women.
In men: ECW OR = 1.407, p = 0.038; Reactance_TR OR = 2.764, p = 0.030
Associations were not statistically significant in women in sex-stratified analyses
Formal interaction testing did not support a statistically significant sex difference: sex × ECW p = 0.573; sex × Reactance_TR p = 0.605
Authors attributed the apparent sex difference to lower statistical power in the smaller female subgroup rather than a true biological interaction
Methods
The study sample consisted of 232 participants with two TCM constitutional types recruited from a community-based health screening program.
129 participants had the Harmonious constitution and 103 had the dampness constitution (phlegm-dampness and damp-heat constitutions combined)
Participants were consecutively recruited in a cross-sectional design
Measurements included whole-body and segmental fluid distribution, bioelectrical parameters, and grip strength
The dampness constitution category encompassed both phlegm-dampness and damp-heat TCM constitutional subtypes
Conclusions
ECW and Reactance_TR are proposed as preliminary candidate indicators for the objective identification of the dampness constitution, pending validation in independent populations.
Authors conclude these parameters 'constitute preliminary candidate indicators for the objective identification of the dampness constitution'
The authors note the findings require validation in independent populations
The study aimed to provide objective bioelectrical impedance analysis parameters for identifying a TCM constitutional category
The cross-sectional design and single-center community sample are acknowledged limitations requiring further study
What This Means
Traditional Chinese Medicine (TCM) classifies people into different body constitution types, including a 'dampness constitution' (which includes phlegm-dampness and damp-heat types) thought to be associated with excess fluid or metabolic imbalance in the body. This study investigated whether objective, measurable physical parameters obtained through bioelectrical impedance analysis (BIA)—a technology that passes a small electrical current through the body to estimate body composition—could reliably identify people with this constitution type. Among 232 community participants, researchers found that two BIA measurements were independently linked to the dampness constitution: extracellular water (ECW, the amount of fluid outside cells) and trunk reactance (a measure of how trunk tissue resists electrical current, reflecting tissue structure and fluid content).
This research suggests that people classified as having a dampness constitution tend to have higher extracellular fluid levels and altered electrical properties in their trunk region, which the authors interpret as evidence of trunk fluid retention and changes in tissue composition. These associations held up after accounting for other factors and were consistent across multiple statistical sensitivity tests. The associations appeared stronger in men than women in subgroup analyses, though the study lacked enough statistical power to confirm a true sex difference.
The practical implication of this research is that BIA—a widely available, non-invasive clinical tool—may offer a way to objectively measure aspects of TCM constitutional types that are currently assessed through subjective questionnaires and practitioner judgment. However, the authors emphasize that these findings are preliminary, derived from a single community sample, and must be validated in larger, independent populations before they could be used in clinical or research settings.
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He Y, Tian G, Shi B, Zhu X, Xu Z, Li F, et al.. (2026). Identification of Dampness Constitution Based on Bioimpedance Analysis: Independent Associations Between Extracellular Fluid and Trunk Reactance.. Journal of visualized experiments : JoVE. https://doi.org/10.3791/73707