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. 2026 Jun 15;17:120. doi: 10.1186/s13293-026-00940-7

Table 2.

Nitric oxide metabolites and ratios stratified by sex and age class (unadjusted)

Men
[n = 58]
Women
[n = 113]
p sex*age
Median
[1st; 3rd quartile]
β coefficient [95% CI], page Median
[1st; 3rd quartile]
β coefficient [95% CI], page
NO metabolites
L-arginine [µmol/L], 67.9 [58.5;82.0]

0.017

[−0.69 to 0.72];

p = 0.962

67.7 [59.4;81.9]

0.182

[−0.20 to 0.57];

p = 0.349

0.677
 ≤60 years 61.3 [52.0;70.8] 66.6 [63.0;74.4]
 60–<70 years 68.4 [63.4;91.3] 71.3 [65.0;82.0]
 70–<80 years 69.5 [58.4;81.7] 66.3 [58.6;79.7]
 ≥80 years 63.6 [58.6;74.6] 74.0 [59.0;86.0]
L-homoarginine [µmol/L] 1.33 [1.00;1.85]

−0.014

[−0.04 to 0.02]; p = 0.340

1.22 [0.74;1.61]

−0.012

[−0.03 to 0.00]

p = 0.104

0.890
 ≤60 years 1.46 [0.81;2.25] 1.39 [1.02;1.88]
 60–<70 years 1.38 [1.14;1.80] 1.29 [0.72;1.57]
 70–<80 years 1.40 [1.02;1.91] 1.06 [0.78;1.64]
 ≥80 years 1.14 [0.87;1.55] 1.03 [0.68;1.32]
ADMA [µmol/L] 0.62 [0.58;0.68]

0.003

[−0.001 to 0.006];

p = 0.160

0.61 [0.55;0.66]

0.003

[0.001 to 0.005]

p = 0.007

0.936
 ≤60 years 0.62 [0.61;0.65] 0.61 [0.54;0.64]
 60–<70 years 0.59 [0.53;0.62] 0.57 [0.52;0.63]
 70–<80 years 0.66 [0.62;0.72] 0.61 [0.57;0.68]
 ≥80 years 0.61 [0.58;0.64] 0.67 [0.64;0.71]
SDMA [µmol/L] 0.72 [0.58;0.82]

* 0.013

[0.001 to 0.025]; p = 0.035

0.60 [0.52;0.72]

* 0.009

[0.003 to 0.015]

p = 0.002

0.568
 ≤60 years 0.66 [0.57;0.95] 0.52 [0.48;0.60]
 60–<70 years 0.59 [0.56;0.72] 0.59 [0.53;0.70]
 70–<80 years 0.75 [0.63;0.92] 0.62 [0.55;0.75]
 ≥80 years 0.79 [0.65;0.82] 0.77 [0.68;1.03]
L-citrulline [µmol/L] 42.9 [32.3;51.1]

0.662

[−0.00 to 1.32]; p = 0.05

40.3 [33.0;47.5]

0.257

[−0.00 to 0.52]

p = 0.053

0.193
 ≤60 years 34.7 [23.0;45.3] 37.2 [31.1;45.7]
 60–<70 years 34.6 [27.6;50.7] 39.5 [34.1;45.9]
 70–<80 years 42.7 [32.4;52.2] 40.3 [33.9;46.2]
 ≥80 years 44.6 [37.9;49.3] 53.1 [42.4;59.6]
L-lysine [µmol/L] 191 [172;213]

−0.495

[−1.56 to 0.57]; p = 0.357

183 [164;205]

0.413

[−0.26 to 1.08]

p = 0.224

0.172
 ≤60 years 184 [175;195] 177 [151;211]
 60–<70 years 199 [171;221] 182 [165;204]
 70–<80 years 195 [174;213] 182 [164;205]
 ≥80 years 176 [164;182] 195 [185;199]
L-ornithine [µmol/L] 71.9 [59.0;87.6]

0.245

[−0.62 to 1.11]; p = 0.573

71.3 [59.6;82.4]

0.638

[0.16 to 1.11]

p = 0.009

0.422
 ≤60 years 61.4 [55.6;67.9] 63.9 [59.5;73.7]
 60–<70 years 68.9 [61.6;85.1] 66.5 [56.0;81.1]
 70–<80 years 81.6 [66.1;89.4] 72.2 [62.6;82.0]
 ≥80 years 58.0 [54.4;74.4] 87.9 [76.8;108]
Ratios
L-arginine/ADMA ratio 104 [85.3;134]

−0.459

[−1.66 to 0.75]; p = 0.449

117 [97.6;131]

−0.252

[−0.92 to 0.41]

p = 0.454

0.762
 ≤60 years 99.1 [80.7;117] 111 [97.0;132]
 60–<70 years 124 [92.6;153] 123 [109;135]
 70–<80 years 102 [85.1;126] 109 [94.8;124]
 ≥80 years 104 [95.1;118] 98.2 [89.9;132]
L-arginine/L-ornithine ratio 0.96 [0.76;1.10]

−0.002

[−0.01 to 0.01], p = 0.673

1.00 [0.84;1.21]

−0.005

[−0.01 to 0.00],

p = 0.141

0.674
 ≤60 years 1.00 [0.93;1.04] 1.03 [0.95;1.23]
 60–<70 years 1.03 [0.90;1.08] 1.15 [0.85;1.25]
 70–<80 years 0.86 [0.75;1.07] 0.98 [0.78;1.12]
 ≥80 years 1.03 [0.81;1.33] 0.83 [0.75;0.99]
GABR 0.60 [0.52;0.71]

−0.005

[−0.01 to 0.00]; p = 0.078

0.65 [0.55;0.75]

−0.003

[−0.01 to 0.00]

p = 0.153

0.552
 ≤60 years 0.71 [0.63;0.74] 0.66 [0.58;0.80]
 60–<70 years 0.65 [0.59;0.75] 0.70 [0.55;0.80]
 70–<80 years 0.57 [0.50;0.64] 0.63 [0.53;0.69]
 ≥80 years 0.59 [0.53;0.69] 0.52 [0.44;0.65]

Data is presented as median [1st; 3rd quartile]

Sample size of age groups (men/women): ≤60 years (4/16); 60–<70 years (15/40); 70–<80 years (33/47), ≥ 80 years (6/10)

Results show the regression coefficient β for age and the corresponding 95% confidence interval, or the p-value for the interaction of sex*age

* Model did not meet model assumptions and therefore, data was log-transformed