Gender differences in the metabolome of symptomatic obstructive sleep apnoea patients

<bold>Introduction:</bold> Gender differences among obstructive sleep apnoea (OSA) patients in symptoms and polysomnographic parameters have been previously described (Bonsignore et al. Eur Respir Rev 2019;28:190030). <bold>Aims and objectives:</bold> In a prospective observational trial, we assessed the metabolomic differences between genders in a population of symptomatic patients with polysomnography-confirmed OSA. <bold>Methods:</bold> Serum samples were collected from OSA patients in three different time points overnight and analysed with liquid-chromatography mass spectrometry using Absolute IDQTM p180 kit. A total of 186 metabolites were measured. Rank-transformed parameters were compared using general linear model for repeated measures. <bold>Results:</bold> We recruited 51 OSA patients (27 male, 24 female). Altogether, we found 12 metabolites with significantly different concentrations between the genders. Women had significantly higher concentrations of 3 phosphatidylcholines with diacyl residues of C36:2 (p=0.046), C38:3 (p=0.037) and C38:4 (p=0.048), 2 sphingomyelins with acyl residues of C18:1 (p=0.019) and C 20:2 (p=0.035), 3 acylcarnitines: hydroxypropionylcarnitine (p=0.021), propenoylcarnitine (p=0.026) and butenoylcarnitine (p=0.043) and 2 amino acids: glycine (p=0.031) and serine (p=0.035). Men had significantly higher concentrations of 2 amino acids: histidine (p=0.041) and methionine (p=0.038). <bold>Conclusions:</bold> Our study demonstrated for the first time that there are significant differences in the metabolome of female and male OSA patients.