ABSTRACT
PurposeThe causal effects of body fat mass and body fat-free mass on coronavirus disease 2019 (COVID-19) severity remain unclear. Here, we used Mendelian randomization (MR) to evaluate the causal relationships between body fat-related traits and COVID-19 severity. Material and MethodsWe identified single nucleotide polymorphisms associated with body mass index (BMI) and direct measures of body fat (i.e., body fat percentage, body fat mass, and body fat-free mass) in 461,460, 454,633, 454,137, and 454,850 individuals of European ancestry from the UK Biobank, respectively. We then performed two-sample MR to ascertain their effects on severe COVID-19 (cases: 4,792; controls: 1,054,664) from the COVID-19 Host Genetics Initiative. ResultsWe found that an increase in BMI, body fat percentage, and body fat mass by one standard deviation were each associated with severe COVID-19 (odds ratio (OR)BMI = 1.49, 95%CI: 1.19-1.87, P = 5.57x10-4; ORbody fat percentage = 1.94, 95%CI: 1.41-2.67, P = 5.07x10-5; and ORbody fat mass = 1.61, 95%CI: 1.28-2.04, P = 5.51x10-5). Further, we evaluated independent causal effects of body fat mass and body fat-free mass using multivariable MR and revealed that only body fat mass was independently associated with severe COVID-19 (ORbody fat mass = 2.91, 95%CI: 1.71-4.96, P = 8.85x10-5 and ORbody fat-free mass = 1.02, 95%CI: 0.61-1.67, P = 0.945). ConclusionsThis study demonstrates the causal effects of body fat accumulation on COVID-19 severity and indicates that the biological pathways influencing the relationship between COVID-19 and obesity are likely mediated through body fat mass.
ABSTRACT
A laser endoscopy system was developed in 2012. The system allows blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) to be performed as modes of narrow-band light observation; these modes have been reported to be useful for tumor detection and characterization. Furthermore, an innovative endoscopy system using four-light emitting diode (LED) multilight technology was released in 2016 to 2017 in some areas in which laser endoscopes have not been approved for use, including the United States and Europe. This system enables blue light imaging (this is also known as BLI) and LCI with an LED light source instead of a laser light source. Several reports have shown that these modes have improved tumor detection. In this paper, we review the efficacy of BLI and LCI with laser and LED endoscopes in tumor detection and characterization.
