Table 1 Background characteristics of the participants at baseline by BM frequency by sex

From: Bowel movement frequency and risk of colorectal cancer in a large cohort study of Japanese men and women

  BM frequency
  Men Women
Variable 1per day, (n=22 930) Every 2–3 days, (n=2526) Every 4–5 days, (n=222) Every 6 days or less, (n=53) P-valuea 1per day, (n=25 884) Every 2–3 days, (n=9813) Every 4–5 days, (n=1238) Every 6 days or less, (n=263) P valuea
Age (years)
 Mean 57.6 59.7 62.5 65.9 <0.0001 58.4 57.3 57.4 58.8 <0.0001
 s.d. 10.2 11.2 11.3 11.6   9.9 10.5 10.8 11.0  
BMI (kg m2)
 Mean 22.7 22.2 21.7 21.7 <0.0001 23.1 22.6 22.5 22.0 <0.0001
 s.d. 3.0 2.9 3.1 3.6   3.6 3.0 3.1 3.0  
Having green leafy vegetables every day (%) 26.2 26.1 20.7 22.6 0.29 32.5 27.8 27.1 24.7 <0.0001
Daily alcohol drinking (%) 48.4 36.0 33.3 28.3 <0.0001 5.2 4.7 4.3 4.9 0.15
Current smokers (%) 50.3 48.9 51.8 47.2 0.55 4.5 4.7 8.1 11.4 <0.0001
Daily walking time <30 min (%) 25.9 32.3 38.3 50.9 <0.0001 22.4 26.6 31.9 37.3 <0.0001
Having family history of colorectal cancer (%) 2.2 2.1 1.8 0.0 0.71 2.5 2.5 3.1 3.4 0.53
Age of final education completed 20 years (%) 11.8 11.4 8.1 15.1 0.30 5.2 5.6 4.9 4.2 0.29
Use of laxatives (%) 4.6 21.8 46.2 60.5 <0.0001 8.5 24.1 48.5 64.3 <0.0001
Having frequent diarrhoea (%) 20.7 16.5 20.1 18.8 <0.0001 10.7 7.6 6.4 3.8 <0.0001
  1. BM=bowel movement; BMI=body mass index; ANOVA=analysis of variance.
  2. aTest for homogeneity of characteristics between categories of BM frequency, using ANOVA (age, BMI) and χ2 (other variables).