Skip to main content

Table 2 Baseline characteristics of subjects according to availability of TBARS measure and the 15 selected predictors

From: Association between dietary polyphenols intake and an oxidative stress biomarker: interest of multiple imputation for handling missing covariates and outcomes

Total (n = 4,129) Measured TBARS (n = 2,116) Non measured TBARS (n = 2,013) P valuea
No. of subjects (%) Incomplete cases Complete cases Incomplete cases Complete cases
Median [IQR] 1,004 1,112 734 1,279
Gender      <0.0001
 Male 467 (46.5) 538 (48.4) 283 (38.6) 515 (40.3)  
 Female 537 (53.5) 574 (51.6) 451 (61.4) 764 (59.7)  
Age (years) 50 (46 to 55) 49 (46 to 54) 48 (44 to 53) 48 (44 to 53) <0.0001
Intervention group      0.54
 Placebo 471 (46.9) 545 (49.0) 357 (48.6) 593 (46.4)  
 Supplementation 533 (53.1) 567 (51.0) 377 (51.4) 686 (53.6)  
Number of dietary records 12 [10–13] 12 [10–13] 12 [10–13] 12 [10–13] 0.24
Energy intakeb (kcal/d) 1,994 [1,664–2,395] 2,017 [1,660–2,369] 1,965 [1,635–2,326] 1,988 [1,669–2,315] 0.34
Alcohol intake at inclusion (log) (g/d) 2.68 [0.00–3.38] 2.68 [0.00–3.38] 2.68 [0.00–3.09] 2.01 [0.00–3.18] 0.006
 Missing 140 0 138 0  
Smoking status at inclusion      0.18
 Never smoker 475 (50.9) 549 (49.4) 350 (52.1) 665 (52.0)  
 Former smoker 375 (40.2) 424 (38.1) 246 (36.6) 475 (37.1)  
 Current smoker 83 (8.9) 139 (12.5) 76 (11.3) 139 (10.9)  
 Missing 71 0 62 0  
Weight at inclusion (kg) 66 [57–75] 67 [58–77] 64 [56–74] 65 [57–74] 0.004
 Missing 23 0 14 0  
Height at inclusion (cm) 167 [161–173] 168 [161–174] 166 [160–172] 166 [160–172] <0.0001
 Missing 27 0 14 0  
Plasma selenium (μmol/L) 1.08 [0.96–1.20] 1.09 [0.98–1.20] 1.09 [0.98–1.20] 1.11 [1.00–1.23] 0.0003
 Missing 92 0 69 0  
Plasma zinc (μmol/L) 13.20 [12.10–14.30] 13.30 [12.00–14.4] 12.80 [11.70–14.00] 13.10 [11.90–14.35] <0.0001
 Missing 92 0 61 0  
Plasma α-tocopherol (μmol/L) (log) 3.46 [3.31–3.60] 3.41 [3.25–3.56] 3.41 [3.27–3.57] 3.41 [3.25–3.55] <0.0001
 Missing 292 0 284 0  
Plasma β-carotene (μmol/L) (log) −0.64 [−1.05- -0.21] −0.71 [−1.17- -0.29] −0.65 [−1.12- -0.21] −0.66 [−1.11- -0.28] 0.009
 Missing 292 0 284 0  
Retinol (μmol/L) 2.31 [1.90-2.74] 2.16 [1.76-2.55] 2.27 [1.90-2.62] 2.12 [1.78- 2.54] <0.0001
 Missing 292 0 284 0  
Vitamin C (μmol/L) 9.63 [7.77 -11.71] 9.64 [7.44-11.63] 10.18 [7.76-12.19] 9.81 [7.33-12.04] 0.13
 Missing 675 0 362 0  
  1. Abbreviation: IQR interquartile range
  2. apvalues were obtained comparing the 4 groups
  3. bEnergy intake excluding from alcohol