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. Author manuscript; available in PMC: 2022 Oct 1.
Published in final edited form as: Environ Res. 2021 Jun 24;201:111553. doi: 10.1016/j.envres.2021.111553

Table 3.

The significant adjusted associations between short-term exposure to NO2 (predicted models) with metabolomics (multi-pollutant models) at ENT95% significance level

Biochemical Super-pathway Sub-pathway 1 day window, Beta (SE) for individual metabolites 1 day window, p-value for individual metabolites 7 day window, Beta (SE) for individual metabolites 7 day window, p-value for individual metabolites 30 day window, Beta (SE) for individual metabolites 30 day window, p-value for individual metabolites ICA_factor 2 Weight ICA_factor 2 Rank
Hypotaurine Amino Acid Methionine, Cysteine, SAM and Taurine Metabolism −0.013(0.003) 4.62E-07 NS NS NS NS 0.517134 20
Maltotriose Carbohydrate Glycogen Metabolism −0.017(0.004) 7.11E-06 −0.021(0.004) 1.54E-06 −0.022(0.005) 6.54E-06 0.615801 9
3-phosphoglycerate Carbohydrate Glycolysis, Gluconeogenesis, and Pyruvate Metabolism −0.016(0.003) 5.82E-06 NS NS NS NS 0.856077 2
Nicotinamide Cofactors and Vitamins Nicotinate and Nicotinamide Metabolism −0.012(0.002) 6.3E-07 NS NS NS NS 0.514755 22
Dihomolinoleoylcarnitine (C20:2) * Lipid Fatty Acid Metabolism (Acyl Carnitine, Polyunsaturated) −0.008(0.002) 1.16E-05 NS NS NS NS 0.354472 66
Palmitoloelycholine Lipid Fatty Acid Metabolism (Acyl Choline) 0.014(0.003) 5.83E-06 NS NS NS NS −0.44944 37
Palmitoylcholine Lipid Fatty Acid Metabolism (Acyl Choline) 0.013(0.003) 9.48E-06 NS NS NS NS −0.47882 30
Oleoylcholine Lipid Fatty Acid Metabolism (Acyl Choline) 0.014(0.003) 3.33E-06 NS NS NS NS −0.48131 28
Stearoylcholine * Lipid Fatty Acid Metabolism (Acyl Choline) 0.015(0.003) 1.4E-05 NS NS NS NS −0.5512 15
8-hydroxyoctanoate Lipid Fatty Acid, Monohydroxy 0.013(0.003) 1.02E-05 NS NS NS NS −0.30251 95
Linolenate [alpha or gamma; (18:3n3 or 6)] Lipid Long Chain Polyunsaturated Fatty Acid (n3 and n6) NS NS −0.01(0.002) 8.52E-06 NS NS 0.055594 500
Palmitate (16:0) Lipid Long Chain Saturated Fatty Acid NS NS −0.008(0.002) 7.3E-06 NS NS 0.059332 473
1-stearoyl-2-oleoyl-GPS (18:0/18:1) Lipid Phosphatidylserine (PS) −0.013(0.003) 6.87E-06 NS NS NS NS 0.640158 8
Phosphoethanolamine Lipid Phospholipid Metabolism −0.012(0.002) 5.48E-07 NS NS NS NS 0.551825 14
Choline phosphate Lipid Phospholipid Metabolism −0.009(0.002) 2.84E-06 NS NS NS NS 0.422478 46
Sphingadienine Lipid Sphingolipid Synthesis −0.015(0.003) 1.81E-06 NS NS NS NS 0.696453 6
Sphingosine Lipid Sphingosines −0.011(0.002) 8.05E-06 NS NS NS NS 0.56189 13
Adenosine 5’-monophosphate (AMP) Nucleotide Purine Metabolism, Adenine containing −0.015(0.003) 4.08E-06 NS NS NS NS 0.796578 4
X - 18914 Xenobiotics Chemical NS NS NS NS −0.01(0.002) 3.99E-06 0.099545 274

These models were linear mixed-effect regression models (LMEM) with random participant-specific intercepts and simultaneously adjusted for PM2.5, NO2, O3, and temperature (multi-pollutant models) for the same exposure window.

Beta (SE) and p-values presented are from individual metabolites analysis.

All models were adjusted for age (years), body mass index (kg/m2), cigarette pack-years, alcohol intake (< or ≥2 drinks per day), socioeconomic status (income payment and years of education), season (warm/cold), and relative humidity.

Significant metabolites at ENT95% significance level only are presented.

ICA_factor2 rank represents the rank of the corresponding metabolite contributing to factor 2 from the independent component analysis (ICA). Higher rank (and higher weights) means higher contribution to factor 2 of the ICA. We show alongside the weights and ranks of each metabolite that contributes to factor 2 from the ICA only because it was the only significant factor.

Range of facto2-ICA rank is from 1 to 1158 i.e., number of examined metabolites. Range of facto2-ICA weight is from −1 to 1.

The metabolites with an X-XXXX format are unknown but reproducible.

A single asterisk after a metabolite (*) indicates a compound that has not been confirmed based on a standard, but Metabolon is confident in its identity based on a subset of these analytical parameters.

Abbreviations: ENT: Effective/independent number of tests; PM2.5, particulate matter ≤2.5 μm; NO2, nitrogen dioxide; and O3, ozone; ICA, independent component analysis; SE, standard error.