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Table 1 Basic characteristic of study participants

From: Calcium intake may explain the reduction of colorectal cancer odds by dietary selenium - a case-control study in Poland

  Colorectal cancer cases [n = 683] Controls [n = 759] p-value
Gender [n, (%)]      pchi2 = .049
 Men 389 (57.0%) 393 (51.8%)  
 Women 294 (43.0%) 366 (48.2%)
Age      pMW = .010
 mean, (SD) 58.6 (8.0) $ 57.5 (9.0) $  
 median (Q1-Q3) 59.0 (53.0–65.0) 57.0 (50.0–65.0)  
Dukes [n = 464]     
 A (T1, N0, M0) 32 (6.9%)    
 B (T2, N0, M0) 100 (21.6%)    
 B2 (T3–4, N0, M0) 97 (20.9%)    
 C1 (T2, N1–3, M0) 24 (5.2%)    
 C2 (T3–4, N1–3, M0) 98 (21.1%)    
 D (Tx-4, Nx-3, M1) 113 (24.4%)    
Histological grade [n = 129]     
 Grade 1 (G1) 31 (24.0%)    
 Grade 2 (G2) 87 (67.4%)    
 Grade 3 (G3) 11 (8.5%)    
Leisure-time physical activity* [METs-h/week]    [n = 757]   pMW = .301
 mean, (SD) 31.5 (26.4) $ 31.4 (22.5) $  
 median (Q1-Q3) 26.6 (11.6–43.9) 28.3 (13.6–43.8)
BMI [kg/m2]    [n = 757]   pMW = .637
 mean, (SD) 27.4 (4.2)$ 27.6 (9.9) $  
 median (Q1-Q3) 27.0 (24.5–29.7) 27.0 (24.2–29.9)
Smoking [n, (%)] [n = 557]   [n = 675]   pchi2 = .073
 Current smoker 149 (26.8%) 220 (32.6%)  
 Past smoker 164 (29.4%) 175 (25.9%)  
 Non-smoker 244 (43.8%) 280 (41.5%)  
Dietary calcium [mg/d]      pMW = .035
 mean (SD) 712 (299) $ 783 (419) $  
 median (Q1-Q3) 652 (496–856) 688 (491–929)  
Dietary selenium [μg/d]      pMW = .304
 mean (SD) 51 (17) $ 55 (27) $  
 median (Q1-Q3) 49 (39–59) 50 (38–64)  
Total dietary fibre [g/day]      pMW = .718
 mean (SD) 17.9 (6.5) $ 18.5 (7.8) $  
 median (Q1-Q3) 16.8 (13.1–21.4) 16.8 (12.9–22.0)  
Pure alcohol** [g/week]      pMW = .004
 mean (SD) 33.5 (67.7) $ 30.9 (78.6) $  
 median (Q1-Q3) 8.2 (2.8–32.2) 4.8 (2.4–25.5)  
Vitamin C [mg/d]      pMW = .381
 mean (SD) 93 (51) $ 99 (62) $  
 median (Q1-Q3) 78 (58–117) 82 (55–132)  
Vitamin E [mg/d]      pMW = .860
 mean (SD) 9.8 (4.8) $ 10.2 (5.3) $  
 median (Q1-Q3) 8.8 (6.7–11.5) 8.7 (6.4–12.6)  
Taking mineral supplements [n, (%)] 102 (14.9%) 111 (14.6%) pchi2 = .869
Fish consumption [n, (%)]      pchi2 = .891
 No 42 (6.2%) 48 (6.3%)  
 Yes 641 (93.8%) 711 (93.7%)  
  1. Continuous variables were presented as mean (SD) or median (Q1-Q3) and P values were calculated using the Mann-Whitney test; categorical variables were presented as n (%) and P values were calculated using chi-square test
  2. BMI Body mass index, Chi2 Chi-squared test, MW the Mann-Whitney test
  3. $p-value <.05 by the Shapiro-Wilk test for normal distribution
  4. *average adult lifetime physical activity (reported as recreational and at home)
  5. **participants reported their consumption expressed in “standard” drinks, which is an equivalent of 12 fl of regular beer of about 5% alcohol or 5 fl of wine (approximately 12% alcohol) or 1.5 fl of distilled spirits (gin, rum, vodka, whiskey, 40% alcohol). Each “standard” drink contains roughly 14 g of pure alcohol