Florida International University, Department of Biomedical Engineering, Miami, Florida, United States.
Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States.
J Biomed Opt. 2022 Mar;27(3). doi: 10.1117/1.JBO.27.3.030902.
Obesity is a worldwide epidemic contributing directly to several cardiovascular risk factors including hypertension and type 2 diabetes. Wearable devices are becoming better at quantifying biomarkers relevant for the management of health and fitness. Unfortunately, both anecdotal evidence and recent studies indicate that some wearables have higher levels of error when utilized by populations with darker skin tones and high body mass index (BMI). There is an urgent need for a better evaluation of the limits of wearable health technologies when used by obese individuals.
(1) To review the current know-how on changes due to obesity in the skin epidermis, dermis, and subcutis that could affect the skin optical properties; (2) for the green wavelength range, to evaluate the difference in absorption and scattering coefficients from the abdominal skin between individuals with and without elevated BMI. The changes include alterations in layer thickness and cell size, as well as significant differences in chromophores and scatterer content, e.g., water, hemoglobin, collagen, and lipids.
We have summarized literature pertaining to changes in skin and its components in obesity and report the results of our search using articles published between years 1971 and 2020. A linear model was used to demonstrate the absorption and reduced scattering coefficient of the abdominal skin of individuals with and without elevated BMI in the green wavelength range (530 to 550 nm) that is typically found in most wearables.
The general trends indicate a decrease in absorption for both dermis and subcutis and an increase in reduced scattering for both epidermis and dermis. At 544-nm wavelength, a typical wavelength used for photoplethysmography (PPG), the absorption coefficient's relative percentage difference between high and low BMI skin, was 49% in the subcutis, 19% in the dermis, and negligible in the epidermis, whereas the reduced scattering coefficient relative difference was 21%, 29%, and 165% respectively.
These findings suggest that there could be significant errors in the output of optical devices used for monitoring health and fitness if changes due to obesity are not accounted for in their design.
肥胖是一种全球性的流行疾病，直接导致了多种心血管风险因素，包括高血压和 2 型糖尿病。可穿戴设备在量化与健康和健身管理相关的生物标志物方面变得越来越出色。不幸的是，既有轶事证据，也有最近的研究表明，一些可穿戴设备在肤色较深和体重指数（BMI）较高的人群中使用时，误差水平更高。当肥胖个体使用可穿戴健康技术时，迫切需要更好地评估其局限性。
（1）综述肥胖引起的皮肤表皮、真皮和皮下组织变化，这些变化可能会影响皮肤的光学特性；（2）对于绿光范围，评估具有和不具有升高 BMI 的个体之间腹部皮肤的吸收和散射系数差异。这些变化包括层厚度和细胞大小的改变，以及色团和散射体含量的显著差异，例如水、血红蛋白、胶原蛋白和脂质。
我们总结了与肥胖相关的皮肤及其成分变化的文献，并报告了使用 1971 年至 2020 年期间发表的文章进行搜索的结果。线性模型用于展示绿光范围内（530 至 550nm）具有和不具有升高 BMI 的个体腹部皮肤的吸收和降低散射系数，该波长范围通常在大多数可穿戴设备中找到。
总体趋势表明，真皮和皮下组织的吸收减少，表皮和真皮的散射增加。在典型用于光电容积描记法（PPG）的 544nm 波长处，高 BMI 和低 BMI 皮肤之间的吸收系数相对百分比差异在皮下组织中为 49%，真皮中为 19%，表皮中可忽略不计，而散射系数相对差异分别为 21%、29%和 165%。
如果在设计中不考虑肥胖引起的变化，那么用于监测健康和健身的光学设备的输出可能会出现显著误差。
Zotero 插件
