Abstract
Background: Establishing a high-accuracy and non-invasive method is essential for evaluating cardiovascular disease. Skin cholesterol is a novel marker for assessing the risk of atherosclerosis and can be used as an independent risk factor for early assessment of atherosclerotic risk.Methods: we propose a non-invasive skin cholesterol detection method based on absorption spectroscopy. Detection reagents specifically bind to skin cholesterol and react with indicator to produce colored products, the skin cholesterol content can be obtained through absorption spectrum information of colored products detected by noninvasive technology. Gas chromatography is used to measure cholesterol extracted from the skin to verify the accuracy of the noninvasive test method. A total of 163 subjects were divided into normal group(n=58), disease group (n=26) and risk group(n=79). All subjects underwent noninvasive skin cholesterol test. The diagnostic accuracy of the measured value was analyzed by receiver-operating characteristic (ROC) curve.Results: The proposed method is able to identify porcine skin containing gradient concentration of cholesterol and the values measured by non-invasive detection method were significantly correlated with gas chromatography measured results (r=0.9074, n=73, p<0.001). We further evaluated the method on patients with atherosclerosis and high risk population as well as normal group, patients and high risk atherosclerosis group exhibited higher skin cholesterol content than normal group (all P<0.001). The area under the ROC curve for distinguishing Normal/Disease group was 0.8243(95% confidence interval, 0.7165 to 0.9321), however, the area under the ROC curve for distinguishing Normal/Risk group was 0.8488(95% confidence interval, 0.7793 to 0.9182). Conclusions: The method demonstrated its capability of detecting different concentration of skin cholesterol. This non-invasive skin cholesterol detection system may potentially be used as a risk assessment tool for atherosclerosis screening, especially in a large population.