Table 1

Characteristicsa of all interviewed subjects and subjects phenotyped by the caffeine test

All interviewed subjectsPhenotyped subjects
Cases (N = 727)Controls (N = 727)Cases (N = 349)Controls (N = 467)
Male (%)58.158.163.059.3
Female (%)41.941.937.040.7
Japanese (%)60.260.258.260.8
Caucasian (%)25.925.927.828.1
Hawaiian (%)13.913.914.011.1
Family historyb (%)15.49.516.09.2
Ever used aspirin regularly (%)17.628.720.227.4
Age (yrs)67 (58–74)68 (59–74)65 (56–72)67 (57–73)
Education (yrs)12 (12–15)14 (12–16)13 (12–15)14 (12–16)
Pack-years8 (0–34)1 (0–24)8 (0–34)1 (0–25)
Body mass index 5 yrs ago25 (22–28)24 (22–27)25 (22–28)24 (22–26)
Lifetime recreational physical activity (h)2824 (180–9048)4624 (960–11684)3264 (336–9000)4560 (960–11568)
Total calories (kcal)2005 (1532–2600)1894 (1461–2454)2052 (1615–2743)1918 (1415–2411)
NSP from vegetablesc (g/day)2.4 (1.4–3.7)2.8 (1.8–4.4)2.3 (1.2–2.6)2.7 (1.8–4.4)
Total calciumd (mg/day)819 (528–1895)955 (561–2610)790 (520–1743)958 (556–2642)
Red meat (g/day)41 (21–70)37 (19–68)45 (24–76)40 (20–70)
Processed meat (g/day)20 (9–39)15 (6–31)21 (12–41)15 (6–31)
  • a Median (25th–75th percentile), except where indicated.

  • b Percent with family history of CRC among parents and siblings.

  • c Nonstarch polysaccharides (NSP) from vegetable sources.

  • d Calcium from food and supplements. NSP and calcium are adjusted for total caloric intake.