Cell Membrane Capacitance and Characteristic Frequency Among Youth and Adults: Reference Data From NHANES 1999-2000.

Abstract

Objective: Cell membrane capacitance (Cm) and characteristic frequency (fc) are two lesser-studied bioelectrical characteristics that may provide valuable insight into cell membrane integrity, yet reference data on these variables are scant. This study aimed to report normative data for Cm and fc among youth and adult populations. Secondary aims were to compare Cm and fc between subgroups, compare 50 kHz to fc, and explore relationships between fc and fat-free mass (FFM).

Method: A secondary analysis was performed using data from the 1999-2000 U.S. National Health and Nutrition Examination Survey data set, including bioelectrical impedance spectroscopy data from male and female youth (8-17 years) and adults (18-49 years) to report reference data. Mann-Whitney U comparisons between sex and age subgroups and one-sample Wilcoxon rank test comparing fc to the common 50-kHz approximation were also conducted.

Results: Cm and fc ranged among youth (Cm = 0.43-4.57 nF; fc = 20.0-95.0 kHz) and adults (Cm = 0.65-4.68 nF; fc = 26.0-89.0 kHz). The youth group had significantly lower Cm (p < .001) and higher fc (p < .001) than the adults, while males had significantly higher Cm (p < .001) and lower fc (p < .001) than females. Compared to 50 kHz, fc was 9.0 kHz higher in youth (p < .001) and 7.0 kHz lower in adults (p < .001), while being 4.0 kHz lower with all ages combined (p < .001).

Conclusions: Cm appears to mirror expected FFM differences between youths and adults and between males and females, while fc appears to have a largely inverse relationship with FFM, although the relationship is quadratic with a nadir near 35 to 40 kHz in adulthood. Cm and fc may have potential as noninvasive and clinically practical indicators of cell membrane functionality and maturation, although more research is needed to examine longitudinal validity of these measures alongside direct cellular observation.