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. Author manuscript; available in PMC: 2019 Apr 1.
Published in final edited form as: Surg Oncol Clin N Am. 2017 Dec 15;27(2):243–267. doi: 10.1016/j.soc.2017.11.002

Table 3.

Characteristics of studies of fiber and CRC

Study Number of study participants Age of participants Follow-up years CRC incidence Analytic category Analytical comparison, high versus low intake Relative risk (95% CI) Ref
13 case-control studies 5,225 (CRC), 10,349 (Control) Total fiber >31.2 g/day versus <10.1 g/day CRC: 0.53 (0.47–0.61), p<0.0001 Ref (51)
16 case-control and 4 cohort studies 10,948 men and women Total fiber per 100g increase CRC: 0.72 (0.63–0.83) Ref (53)
25 prospective studies Total fiber CRC: 0.90 (0.86–0.94) Ref (52)
EPIC 142,250 men and 335,062 women 35–70 1992–2002 2,869 (Colon), 1,266 (Rectum) Total fiber ≥28.5 g/day versus <16.4 g/day CRC: 0.83 (0.72–0.96), p=0.013 Ref (56)
Cereal fiber ≥12.3 g/day versus <4.64 g/day CRC: 0.87 (0.77–0.99), p=0.003
EPIC 131,985 men and 320,770 women 35–70 1992–2002 2, 819 (CRC) Total fiber CRC: 0.86 (0.75–1.00), p=0.04 Ref (55)
PLCO 57,774 men and women 55–74 1993–2001 733 (CRC) Total fiber ≥12.8 g/1000 kcal versus <9.9 g/1000 kcal Distal colon cancer: 0.62 (0.41, 0.94), p=0.03 Ref (57)
Case-control 30–75 341 (Colon), 265 (Rectum), 613 (Control) Total fiber Men: >14.92 g/day versus <7.73 g/day CRC: 0.38 (0.27–0.55), p<0.01 Ref (60)
Women: >12.65 g/day versus <6.52 g/day
JACC 16,636 men and 26,479 women 40–79 1988–1997 291 (Colon), 142 (Rectum) Total fiber CRC: 0.73 (0.51–1.03), p=0.028 Ref (62)
NIH-AARP DHS 291,988 men and 197,623 women 50–71 1995–2000 2,974 (CRC) Fiber from grains >5.7 g/1000 kcal versus <1.7 g/1000 kcal CRC: 0.86 (0.76–0.98), P=0.01 Ref (65)
HELGA 38,841 men and 69,159 women 40–65 1991–2002 680 (Colon), 399 (Rectum) Whole-grain wheat Men: >9 g/day versus ≤1 g/day CRC: 0.65 (0.50–0.84) Ref (66)
Women: >36 g/day versus ≤3 g/day
13 prospective cohort studies 725,628 men and women 6 to 20 years Total fiber >30 g/day versus <10 g/day non-significant associations Ref (54)
HPFS and NHS 47,279 men and 76,947 women 40–75/30–55 1986–2010/1980–2010 1,202 (Colon), 310 (Rectum) Total fiber >14 g/1000 kcal versus <8 g/1000 kcal non-significant associations Ref (58)
WHS 36,976 women 45+ 1993–2003 223 (CRC) Total fiber ≥23.1 g/day versus <12.5 g/day non-significant associations Ref (59)
SWHS 73,314 women 40–70 1997–2005 283 (CRC) Total fiber >13.45 g/day versus <7.3 g/day non-significant associations Ref (61)
JPHC 65,803 men and 67,520 women 45–74 1995–2006 742 (Colon) and 375 (Rectum) Total fiber Men: >18.7 g/day versus <6.4 g/day non-significant associations Ref (63)
Women: >20 g/day versus <8.3 g/day
DCH 26,630 men and 29,189 women 50–64 1993–2009 461 (Colon), 283 (Rectum) Total whole-grain >160 g/dat versus ≤75 g/day non-significant associations Ref (68)
NOWAC 78,254 women 40–70 1996–2006 509 (Colon), 218 (Rectum) whole-grain bread 180–240 g/day versus 0 non-significant associations Ref (69)