3D	3-dimensional
AUC	area under the receiver operating characteristic curve
BMI	body mass index
CE	cholesterol ester
Cer	ceramide
COPD	chronic obstructive pulmonary disease
DG	diacylglycerol
FA	fatty acid
Hex2Cer	dihexaglycosylceramide
FEV1	Forced expiratory volume in one second
FVC	forced vital capacity
HexCer	hexaglycosylceramide
IS	internal standard
LC-MS	liquid chromatography–mass spectrometry
LPC	lyso-phosphatidylcholine
LPC-O	lyso-phosphatidylcholine with alkyl substituents
LPE	lyso-phosphatidylethanolamine
LPE-O	lyso-phosphatidylethanolamine with alkyl substituents
MS/MS	tandem mass spectrometry
MTBE	methyl tert-butyl ether
PC	phosphatidylcholine
PC-O	alkyl- and alkenyl-substituted phosphatidylcholine
PE	phosphatidylethanolamine
PE-O	alkyl- and alkenyl-substituted phosphatidylethanolamine
PG	phosphatidylglycerol
PI	phosphatidylinositol
PLS-DA	projection to latent structures discriminant analysis
PS	phosphatidylserine
QC	quality control
ROC	receiver operating characteristic
RSD	relative standard deviation
SCOPD	stable chronic obstructive pulmonary disease
SM	sphingomyelin
TCM	traditional Chinese medicine
TG	triacylglycerol
tR	retention time
UHPLC-Q-orbitrap-MS	ultra-high performance liquid chromatography–quadrupole–orbitrap–mass spectrometry
VIP	variable importance in projection