Table 2. Effects of gender on ranked coefficients of variation (CV) from paired 24-h urinary measurements of urinary ammonium (NH3), calcium (Ca), chloride (Cl), citrate (Cit), potassium (K), magnesium (Mg), sodium (Na), oxalate (Ox), phosphorus (P), sulfate (SO4), uric acid (UA) and urine urea nitrogen (UN) adjusted for creatinine, urinary volume, age and weight in the complete population of 6,758 females and 9,024 males aged 16–80, and in individuals aged 16–45 and 56–80 in a stepwise backward regression (P acceptance≤0.1).
| All | 16–45 | 56–80 | ||||||||||
| Trait (units) | β sex (SE) | F | Pnom | r 2 | β sex (SE) | F | P nom | r 2 | β sex (SE) | F | P nom | r 2 |
| Ca | −72.8 (81.9) | 0.79 | 0.3745 | 0.0673 | −126.8 (126.0) | 1.01 | 0.3145 | 0.0496 | 144.2 (133.0) | 1.18 | 0.2782 | 0.0907 |
| Cit | 12.0 (83.6) | 0.02 | 0.8861 | 0.0263 | 399.0 (124.7) | 10.2 | 0.0014* | 0.0268 | −476.0 (133.5) | 12.7 | 0.0002** | 0.0367 |
| Cl | −162.5 (72.1) | 5.08 | 0.0242 | 0.114 | −99.7 (111.3) | 0.80 | 0.3702 | 0.0888 | −297.8 (125.8) | 5.60 | 0.0180 | 0.1364 |
| Cr | −116.3 (81.0) | 2.06 | 0.1508 | 0.0149 | −36.3 (128.2) | 0.08 | 0.7769 | 0.0124 | −230.7 (134.4) | 2.95 | 0.0861 | 0.0096 |
| K | 132.4 (80.2) | 2.72 | 0.0990 | 0.0487 | 285.0 (120.0) | 5.67 | 0.0173 | 0.0390 | −52.7 (131.7) | 0.16 | 0.6893 | 0.0534 |
| Mg | −186.3 (81.0) | 5.29 | 0.0215 | 0.0285 | −139.0 (129.0) | 1.16 | 0.2816 | 0.0191 | −365.4 (137.8) | 7.03 | 0.0080† | 0.0364 |
| Na | −155.0 (75.7) | 4.19 | 0.0406 | 0.116 | −168.7 (111.6) | 2.28 | 0.1307 | 0.0913 | −178.9 (125.0) | 2.05 | 0.1525 | 0.1363 |
| NH4 | 42.0 (83.7) | 0.25 | 0.6165 | 0.0230 | −62.6 (130.6) | 0.23 | 0.6318 | 0.0194 | 132.8 (132.9) | 1.00 | 0.3178 | 0.0299 |
| Ox | 184.0 (80.8) | 5.19 | 0.0227 | 0.0332 | 16.3 (130.6) | 0.02 | 0.9009 | 0.0278 | 287.1 (140.0) | 4.21 | 0.0403 | 0.0442 |
| P | −278.6 (74.1) | 14.1 | 0.0002** | 0.0694 | −207.6 (116.6) | 3.17 | 0.0752 | 0.0545 | −295.9 (129.2) | 5.25 | 0.0220 | 0.0750 |
| SO4 | −123.9 (79.1) | 2.45 | 0.1174 | 0.0348 | 29.9 (125.2) | 0.06 | 0.8114 | 0.0314 | −166.6 (137.3) | 1.47 | 0.2253 | 0.0363 |
| UA | 85.7 (78.2) | 1.20 | 0.2728 | 0.0937 | 6.20 (125.5) | 0.0 | 0.9606 | 0.0863 | 45.4 (139.7) | 0.11 | 0.7455 | 0.1065 |
| UN | −60.0 (72.8) | 0.68 | 0.4098 | 0.0971 | −6.28 (123.8) | 0.0 | 0.9596 | 0.0865 | −98.7 (125.6) | 0.62 | 0.4321 | 0.1210 |
Significance (below) is corrected for multiple observations via False Discovery Rate [Verhoeven, 2005 #22836]. Nominal P-value (P nom) is reported at acceptance or removal from the model during the stepwise procedure. Units indicates original values used in CV calculation.
P nom = nominal P-value.
*
P FDR<0.05,
**
P FDR<0.01.
Correlation coefficients (r 2) refer to the complete model correlation, or model fit at rejection of nonsignificant terms via backwards regression (removal at P>0.1).
Negative β indicates lower female CV; positive β higher male CV.