Skin Tissue Water Assessed via Tissue Dielectric Constant Measurements in Persons With and Without Diabetes Mellitus

Objective. To determine if skin tissue water (STW) in persons with diabetes mellitus (DM) is less than in persons without DM (NO-DM). Background. Microvascular and other DM-related skin changes may cause skin dryness and other complications. However, no definitive data describing STW differentials exists. Herein the skin’s tissue dielectric constant (TDC) that is directly proportional to STW was used to determine if differences in TDC are detectible between NO-DM vs. DM subjects. Methods. TDC was measured bilaterally on forearms and on foot dorsum of 18 persons with DM and 18 persons without DM. Measurements were made in triplicate with subjects supine to skin-depths of 2.5, 1.5 and 0.5 mm. NODM and DM groups did not differ by age (54.2±18.4 vs. 62.7±12.5 years, p = 0.21) or BMI (28.4±4.2 vs. 29.9±5.2 Kg/m2, p = 0.36). DM duration was 133±132 months and average HbA1c was 7.4±1.4. Results. Forearm TDC values did not differ between NO-DM and DM groups for any depth being 27.5±3.2 vs. 28.8±3.8 at 2.5mm; 30.5±2.4 vs. 31.8±3.5 at 1.5mm and 32.4±3.9 vs. 34.5±4.5 at 0.5mm. Contrastingly, TDC values were significantly greater (p < 0.05) at the foot for the DM group at all depths being (NODM vs. DM) 29.1±4.1 vs. 33.3±6.4 at 2.5mm; 28.9±3.5 vs. 32.5±5.9 at 1.5mm and 28.3±5.1 vs. 31.9±4.2 at 0.5mm. Conclusions. Contrary to expectations, persons with DM had greater, not lesser skin tissue water in the foot dorsum. This elevation may reflect previously undetected DM-related pre-clinical edemas. If true, the TDC-method may be a useful screening tool. Further testing is indicated.