PT - JOURNAL ARTICLE AU - Gao, Shangzhi AU - Zhuo, Zhu AU - Hutchinson, John AU - Su, Li AU - Christiani, David C TI - Metabolomic profiling identifies plasma sphingosine 1-phosphate levels associated with welding exposures AID - 10.1136/oemed-2020-106918 DP - 2021 Apr 01 TA - Occupational and Environmental Medicine PG - 255--261 VI - 78 IP - 4 4099 - http://oem.bmj.com/content/78/4/255.short 4100 - http://oem.bmj.com/content/78/4/255.full SO - Occup Environ Med2021 Apr 01; 78 AB - Background Despite a number of known health hazards of welding fume exposure, it is unclear how exposure affects the human metabolome.Objective We assessed the metabolic profiles of welders before and after a 6-hour welding shift, controlling for circadian rhythm of metabolism on a non-welding day.Methods Welders were recruited from a training centre in Quincy, Massachusetts, in 2006 and 2010–2012 and donated blood samples on a welding shift day before and after work, as well as on a non-welding day spent in an adjacent classroom. In total, we collected 509 samples from 74 participants. Liquid chromatography–mass spectrometry quantified 665 metabolites from thawed plasmas. Metabolites with significant time (afternoon compared with morning) and day (welding/classroom) interactions were identified by two-way analysis of variance, and the overnight changes were evaluated.Results Sphingosine 1-phosphate (S1P) and sphingasine 1-phosphate (SA1P) exhibited significant interaction effects between day and time with false discovery rate-adjusted p values of 0.03 and <0.01, respectively. S1P, SA1P and sphingosine shared similar trends over time: high relative levels in the morning of a non-welding day declining by afternoon, but with lower starting levels on a welding day and no decline. There was no obvious pattern related to current smoking status.Conclusion S1P and SA1P profiles were different between welding day and classroom day. The S1P pathway was disrupted on the day of welding exposure. The levels of S1P, SA1P and sphingosine were highly correlated over time. S1P is a signalling lipid with many vital roles; thus, the underlying mechanism and clinical implications of this alteration need further investigation.