A Simple Electrical Reading of the Body May Signal Hearing Loss Before Symptoms Strike

A routine measurement that takes seconds in a clinic—a small, painless electrical probe of the body’s composition—may quietly reveal how well a person’s ears are aging. A new study drawing on nationally representative data from South Korea reports that adults with a lower bioelectrical phase angle, an index derived from bioelectrical impedance analysis, had measurably worse hearing on pure-tone audiometry than their peers with higher values. The association held after accounting for age, sex, body mass index, hypertension, diabetes, smoking, and alcohol use, suggesting that this single electrical signature captures something about systemic physiological reserve that conventional body measurements miss.

The research, published in GeroScience by Ho Yun Lee, Seung-Ho Shin, and Sung Wan Byun of Ewha Womans University College of Medicine, analyzed 5,436 adults aged 40 or older from the 2022–2023 Korea National Health and Nutrition Examination Survey (KNHANES). Phase angle is calculated from resistance and reactance recorded when a weak alternating current at 50 kilohertz passes through the body. Resistance reflects how strongly the body’s fluids impede the current, while reactance reflects the capacitive behavior of cell membranes—essentially, how intact and functional those membranes are. A higher phase angle therefore signals healthier cell membranes, a better balance of intracellular to extracellular fluid, and greater nutritional and functional reserve. A lower value has previously been linked to frailty, sarcopenia, malnutrition, disability, and mortality.

The technical details of the hearing assessment matter here. Audiologists computed the speech-frequency pure-tone average from thresholds at 0.5, 1, 2, and 4 kilohertz in each ear, taking the better ear as the primary outcome. They also calculated a high-frequency threshold from 4 and 8 kilohertz, the range where age-related hearing loss typically first appears. Hearing loss was defined as a better-ear pure-tone average of 25 decibels hearing level or worse, the conventional clinical cutoff. All analyses applied complex survey weights to make the sample representative of the entire noninstitutionalized Korean population, and the models progressed through stages of adjustment, from age and sex alone to the full panel of metabolic and lifestyle covariates.

The results were strikingly graded. Participants in the lowest sex-specific phase angle quartile had an average better-ear pure-tone average of 25.9 decibels, while those in the highest quartile averaged just 14.5 decibels. High-frequency thresholds fell from 43.6 to 24.8 decibels across the same gradient. Most dramatically, the prevalence of audiometric hearing loss dropped from 48.3 percent in the lowest quartile to 11.8 percent in the highest. In the fully adjusted regression models, each one-degree increase in phase angle was associated with a 1.50-decibel lower better-ear pure-tone average and a 1.51-decibel lower better-ear high-frequency threshold, both highly statistically significant. Each additional degree also corresponded to a 21 percent reduction in the odds of audiometric hearing loss, with an odds ratio of 0.79.

Perhaps the most intriguing finding emerged from an exploratory comparison with younger participants. When the researchers extended their analysis to people aged 12 to 39, the association between phase angle and hearing vanished entirely—coefficients hovered near zero and were nowhere near statistical significance. Among adults 40 and older, however, the association remained robust. This age-dependent pattern suggests that phase angle is not a general marker of hearing status across the lifespan but rather becomes informative specifically in the context of systemic aging, when physiological reserve begins to erode and the cochlea becomes vulnerable to cumulative metabolic and vascular stress.

The frequency-specific results added another layer of complexity. Inverse associations between phase angle and hearing thresholds appeared across the tested frequencies, but the estimates were largest and most consistent at low-to-mid frequencies, particularly around 2 kilohertz, and weaker at 8 kilohertz. That pattern diverges from the classical high-frequency-dominant configuration of presbycusis, which is typically attributed to degeneration of the basal turn of the cochlea. The authors are careful to frame this as hypothesis-generating rather than evidence of a distinct mechanism, but it hints that systemic reserve may influence cochlear structures differently than chronological aging alone does.

What biological pathways could connect a whole-body electrical measurement to the delicate sensory machinery of the inner ear? The cochlea is an extraordinarily metabolically active organ, and its energy supply depends on the stria vascularis, a vascularized structure that maintains the ionic gradients hair cells require to transduce sound. Chronic low-grade inflammation, oxidative stress, and vascular compromise—all conditions associated with lower phase angle in prior research—could degrade these systems over decades. Alterations in cellular membrane integrity and fluid balance, which phase angle directly reflects, may parallel changes in inner-ear homeostasis. The supplementary analyses bolster this systemic interpretation: higher phase angle was also associated with better quality-of-life scores on the EQ-5D, greater maximum handgrip strength, and lower odds of low grip strength among older adults.

Causality, however, remains firmly open. This was a cross-sectional study, capturing a single moment in time, so it cannot establish whether low phase angle precedes hearing decline or merely accompanies it. Genetic epidemiology complicates the picture further: a bidirectional Mendelian randomization study found no robust forward causal effect of body constitution on hearing loss, and a UK Biobank analysis observed associations between body composition and sensorineural hearing loss without clear genetic support for causation, pointing instead to shared genetic architecture or reverse pathways. Consistent with this caution, the associations in the present study survived adjustment for fat-free mass and percent body fat, indicating that phase angle carries information beyond body composition—but the authors explicitly state that the findings do not imply raising phase angle would improve hearing.

The study also has measurement caveats worth noting. Year-specific sensitivity analyses showed stronger associations in 2022, when a dedicated bioelectrical impedance survey weight was available, and attenuated, non-significant estimates in 2023, with formal heterogeneity between survey years. Residual confounding from lifetime noise exposure, ototoxic medications, socioeconomic factors, and prior otologic disease cannot be excluded, and phase angle itself can be influenced by hydration status and device characteristics, though KNHANES uses standardized examination protocols. Subgroup analyses by sex and age showed numerically larger associations in men and in adults 65 and older, but formal heterogeneity testing did not reach significance, so these patterns should be treated as exploratory.

The clinical message, for now, is one of integration rather than replacement. Phase angle is not a substitute for audiometry, and the authors caution that longitudinal validation is required before any screening application could be considered. But the findings reframe hearing loss as something more than an isolated ear problem: it appears to travel with the broader erosion of cellular integrity and physiological reserve that defines functional aging, alongside frailty, falls, depression, and dementia. If future cohort studies confirm that phase angle predicts hearing decline ahead of symptoms, a measurement already embedded in routine body-composition assessments could become an early, inexpensive flag for one of aging’s most common and most undertreated sensory impairments.

Subject of Research: Association between bioelectrical phase angle and audiometric hearing loss in middle-aged and older adults

Article Title: Lower bioelectrical phase angle is associated with audiometric hearing loss in middle-aged and older adults

Article References: Lee, H. Y., Shin, S.-H., & Byun, S. W. (2026). Lower bioelectrical phase angle is associated with audiometric hearing loss in middle-aged and older adults. GeroScience. https://doi.org/10.1007/s11357-026-02528-w

Image Credits: AI Generated

DOI: 10.1007/s11357-026-02528-w

Keywords: bioelectrical phase angle, hearing loss, audiometry, aging, bioelectrical impedance analysis, KNHANES, physiological reserve, sensory aging, cochlea, frailty, body composition, GeroScience