Thermophysiological BioEnergy Index as a Biomarker of Biological Ageing: A Large-Scale Microwave Radiometry Study

Area of Science:

• Physiological sciences
• Biomedical engineering
• Gerontology

Background:

• Biological ageing involves changes in metabolism, microvascular function, and thermoregulation.
• These changes impact tissue heat dynamics, reflecting integrated physiological processes.
• Passive microwave radiometry (MWR) offers non-invasive deep-tissue bioenergy emission detection.

Purpose of the Study:

• To evaluate a thermophysiological Bioenergetic Index (BEI) as an age-referenced marker.
• BEI integrates deep-tissue microwave emission and surface temperature data.
• The study aimed to correlate BEI with chronological age in women.

Main Methods:

• Analysis of breast thermophysiology data from 36,391 women (aged 20-80).
• Supervised machine learning models trained on thermal features to predict chronological age.
• Performance assessed using MAE, RMSE, and R²; data aggregated into 5-year age bins.

Main Results:

• Individual age prediction achieved MAE ≈ 3.5 years, RMSE ≈ 5.4 years, R² ≈ 0.76.
• Population-level analysis revealed a nonlinear ageing trajectory with midlife decline and late-life stabilization.
• Grouped data improved correspondence by reflecting population trends, not individual prediction accuracy.

Conclusions:

• Thermophysiology exhibits a strong ageing-related signal in women's breasts.
• Thermophysiology shows promise as an age-referenced physiological marker.
• Longitudinal and outcome-based validation are required for clinical application.