Age‐related changes in male forearm skin‐to‐fat tissue dielectric constant at 300 MHz

Abstract

Prior research suggests that tissue dielectric constant (TDC) values are useful to assess localized skin water in females for early diagnosing breast cancer treatment-related lymphoedema and TDC values in young adults have shown gender differences. However, no TDC data are available for older males nor have ageing effects been studied despite known shifts in water state and other skin age-related changes. Thus our goals were to (i) characterize TDC values at various skin depths in young and older males, (ii) determine the dependence of these values on body composition parameters and (iii) establish inter-arm TDC ratios for use as normal male reference values. TDC measurements were made to depths of 0·5, 1·5, 2·5 and 5·0 mm bilaterally on volar forearm skin in 60 males in three groups of 20 that had mean ages ± SD of 24·0 ± 0·9, 40·0 ± 12·9 and 71·0 ± 8·0 years. Total body fat and water percentages were determined via bioimpedance at 50 KHz. Results showed that (i) for all age groups TDC values decreased with increasing depth, (ii) TDC values were not statistically different among age groups except at a depth of 0·5 mm, (iii) TDC values were highly negatively correlated with total body fat and (iv) inter-arm ratios varied little among age groups and depths. It is concluded that (i) age-related larger TDC values at only the shallowest depth is consistent with skin water shifting state from bound to more mobile in the oldest group and (ii) inter-arm ratios at any depth provide a basis to test for unilateral oedema.

Skin tissue dielectric constant in women with high body fat content

“…Although there are limited data in the literature on facial skin TDC values, there is sufficient data to compare the present high BMI and fat mass group with measurements in women who had either normal range BMI values or similar BMI values as measured in the jowl area. The average jowl TDC value of the present group (34.1 ± 4.3) is close to the value of 37.5 ± 4.8 reported for a similar depth in a group of 32 women of a slightly older age (56.4 ± 7.6 years) with an average BMI (29.0 ± 6.4 Kg/m 2 ) close to that of the present studied group (31.8 ± 6.7 Kg/m 2 ). Further, jowl TDC values (36.8 ± 6.2) reported in a group of 35 younger women who had normal BMI values (22.8 ± 4.1 Kg/m 2 ) were also similar to those measured in the high BMI group included in the present study.…”

Subepidermal moisture detection of heel pressure injury: The pressure ulcer detection study outcomes

“…The population for this study was frail older adults and that may limit generalisability. However, others have shown no effect of age on measures of SEM at the 2.5 mm depth (as was used in this study) but only on more superficial depth measures . Further, there was a low correlation between SEM values and age ( r = .18 and r = .19 for right and left heel, respectively) in this study although as the mean age was 76.5 this may only indicate that little difference exists between SEM values across older ages.…”

The revised EEMCO guidance for the in vivo measurement of water in the skin

“…The negative correlation between TDC values and total body fat percentage is seen as consistent with the increased fat percentage as a function of depth. In the assessment of skin features as the primary study aim of a study via TDC, the confounding influence of underlying subcutaneous fat and body composition must be taken into account …”

“…In the assessment of skin features as the primary study aim of a study via TDC, the confounding influence of underlying subcutaneous fat and body composition must be taken into account. 15…”