PDF(Pubmed)
Abstract：
BACKGROUND: Skin hydration (SKH) measurements are used for multiple purposes: to study skin physiology, to clinically investigate dermatological issues, and to assess localized skin water in pathologies like diabetes and lymphedema. Often the volar forearm is measured at various times of day (TOD). This report aims to characterize intra-day variations in volar forearm SKH to provide guidance on expected TOD dependence.
METHODS: Forty medical students (20 male) self-measured tissue dielectric constant (TDC) on their non-dominant forearm in triplicate as an index of local skin tissue water every 2 h starting at 0800 and ending at 2400 h. All were trained and pre-certified in the procedure and had whole-body fat (FAT%) and water (H2O%) measured. Day average TDC (TDCAVG) was determined as the average of all time points expressed as mean ± SD.
RESULTS: Males versus females had similar ages (25.1 ± 2.2 years vs. 25.1 ± 1.5 years), higher H2O% (56.6 ± 5.0 vs. 51.8 ± 5.7, p = 0.002), and higher TDCAVG (32.7 ± 4.1 vs. 28.5 ± 5.1, p = 0.008). TDC values were not significantly impacted by H2O% or FAT%. Female TDC exhibited a significant decreasing trend from morning to night (p = 0.004); male TDC showed no trend.
CONCLUSIONS: Skin water assessed by TDC shows some intra-day variations for females and males but with quite different temporal patterns. Clinical relevance relates to the confidence level associated with skin hydration estimates when measured at different times of day during normal clinic hours which, based on the present data, is expected to be around 5% for both males and females.
METHODS: Forty medical students (20 male) self-measured tissue dielectric constant (TDC) on their non-dominant forearm in triplicate as an index of local skin tissue water every 2 h starting at 0800 and ending at 2400 h. All were trained and pre-certified in the procedure and had whole-body fat (FAT%) and water (H2O%) measured. Day average TDC (TDCAVG) was determined as the average of all time points expressed as mean ± SD.
RESULTS: Males versus females had similar ages (25.1 ± 2.2 years vs. 25.1 ± 1.5 years), higher H2O% (56.6 ± 5.0 vs. 51.8 ± 5.7, p = 0.002), and higher TDCAVG (32.7 ± 4.1 vs. 28.5 ± 5.1, p = 0.008). TDC values were not significantly impacted by H2O% or FAT%. Female TDC exhibited a significant decreasing trend from morning to night (p = 0.004); male TDC showed no trend.
CONCLUSIONS: Skin water assessed by TDC shows some intra-day variations for females and males but with quite different temporal patterns. Clinical relevance relates to the confidence level associated with skin hydration estimates when measured at different times of day during normal clinic hours which, based on the present data, is expected to be around 5% for both males and females.
摘要：
背景：皮肤水合（SKH）测量用于多种目的：研究皮肤生理学，临床调查皮肤病学问题，并评估糖尿病和淋巴水肿等病理中的局部皮肤水分。通常在一天中的不同时间(TOD)测量手掌前臂。本报告旨在表征掌侧前臂SKH的日内变化，以提供有关预期TOD依赖性的指导。
方法：40名医学生（20名男性）自我测量其非优势前臂的组织介电常数（TDC），一式三份，作为每2小时从0800开始的局部皮肤组织水的指标，在2400h结束。所有人都经过培训并在程序中进行了预认证，并测量了全身脂肪（FAT％）和水（％H2O）。天平均TDC(TDCAVG)被确定为表示为平均值±SD的所有时间点的平均值。
结果：男性与女性的年龄相似（25.1±2.2岁与25.1±1.5年)，更高的H2O%(56.6±5.0与51.8±5.7，p=0.002），和更高的TDCAVG（32.7±4.1vs.28.5±5.1，p=0.008）。TDC值不受H2O%或FAT%的显著影响。女性TDC从早到晚呈显著下降趋势(p=0.004),男性TDC无趋势。
结论：通过TDC评估的皮肤水显示出女性和男性的日间变化，但时间模式差异很大。临床相关性涉及在正常临床时间内的一天中的不同时间测量时与皮肤水合作用估计相关的置信水平，根据目前的数据，预计男性和女性的比例都在5%左右。
方法：40名医学生（20名男性）自我测量其非优势前臂的组织介电常数（TDC），一式三份，作为每2小时从0800开始的局部皮肤组织水的指标，在2400h结束。所有人都经过培训并在程序中进行了预认证，并测量了全身脂肪（FAT％）和水（％H2O）。天平均TDC(TDCAVG)被确定为表示为平均值±SD的所有时间点的平均值。
结果：男性与女性的年龄相似（25.1±2.2岁与25.1±1.5年)，更高的H2O%(56.6±5.0与51.8±5.7，p=0.002），和更高的TDCAVG（32.7±4.1vs.28.5±5.1，p=0.008）。TDC值不受H2O%或FAT%的显著影响。女性TDC从早到晚呈显著下降趋势(p=0.004),男性TDC无趋势。
结论：通过TDC评估的皮肤水显示出女性和男性的日间变化，但时间模式差异很大。临床相关性涉及在正常临床时间内的一天中的不同时间测量时与皮肤水合作用估计相关的置信水平，根据目前的数据，预计男性和女性的比例都在5%左右。
