38 research outputs found

    Noninvasive Body Fat Burn Monitoring from Exhaled Acetone with Si-doped WO3-sensing Nanoparticles

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    Obesity is a global health threat on the rise, and its prevalence continues to grow. Yet suitable biomedical sensors to monitor body fat burn rates in situ, to guide physical activity or dietary interventions toward efficient weight loss, are missing. Here, we introduce a compact and inexpensive breath acetone sensor based on Si-doped WO3 nanoparticles that can accurately follow body fat burn rates in real time. We tested this sensor on 20 volunteers during exercise and rest and measured their individual breath acetone concentrations in good agreement with benchtop proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS). During exercise, this sensor reveals clearly the onset and progression of increasing breath acetone levels that indicate intensified body fat metabolism, as validated by parallel venous blood β-hydroxybutyrate (BOHB) measurements. Most importantly, we found that the body fat metabolism was especially pronounced for most volunteers during fasting for 3 h after exercise, with strong variation between subjects, and this was displayed correctly by the sensor in real-time. As a result, this simple breath acetone sensor enables easily applicable and hand-held body fat burn monitoring for personalized and immediate feedback on workout effectiveness that can guide dieting as well

    Minimum important difference of the Epworth Sleepiness Scale in obstructive sleep apnoea: estimation from three randomised controlled trials

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    BACKGROUND The Epworth Sleepiness Scale (ESS) is a widely used tool for assessing sleepiness in patients with obstructive sleep apnoea (OSA). We aimed to estimate the minimal important difference (MID) in patients with OSA. METHODS We used individual data from three randomised controlled trials (RCTs) in patients with OSA where the preintervention to postintervention change in ESS was used as a primary outcome. We used anchor-based linear regression and responder analysis approaches to estimate the MID. For anchors, we used the change in domains of the Functional Outcomes of Sleep Questionnaire and 36-Item Short Form Health Survey. We also used the distribution-based approaches Cohen's effect size, SE of measurement and empirical rule effect size to support the anchor-based estimates. The final MID was determined by triangulating all estimates to a single MID. FINDINGS A total of 639 patients with OSA were included in our analyses across the three RCTs with a median (IQR) baseline ESS score of 10 (6-13). The median (IQR) ESS change score overall was -2 (-5 to 1). The anchor-based estimates of the MID were between -1.74 and -4.21 points and estimates from the responder analysis were between -1 and -3 points. Distribution-based estimates were smaller, ranging from -1.46 to -2.36. INTERPRETATION We propose an MID for the ESS of 2 points in patients with OSA with a disease severity from mild to severe. This estimate provides the means to plan trials and interpret the clinical relevance of changes in ESS. TRIAL REGISTRATION NUMBER Provent, NCT01332175; autoCPAP trial, NCT00280800; MOSAIC,ISRCTN (3416388)
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