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Table 15 Studies examining the relationship between physical activity and colon cancer.

From: A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults

Publication Country Study Design Quality Score Objective Population Methods Outcome Comments and Conclusions
Hou et al 2004 [272] To examine the effect of various forms of PA on colon cancer risk, with particular attention to commuting PA. • n = 931 case, 1,552 control PA assessment: Interview for the following variables    • Number of cases: 931 Regular frequent PA over a long period of time reduces risk of CC.
China   • Sex: Men and women   Multivariate OR (95% CI) by OPA, men  
        • G1 = 1.00 (referent)  
Case control   • Age: 30-74 yr OPA (kJ/min)    • G2 = 1.23 (0.93-1.64)  
D & B score = 14   • Characteristics: Case: diagnosed with CC. controls: selected randomly from residents of urban Shanghai. G1 = <8    • G3 = 0.81 (0.59-1.19)  
    G2 = 8-12 p = 0.10  
    G3 = >12   
    Commuting PA (MET hr/wk) Multivariate OR (95% CI) by OPA, women  
    G1 = <48.3    • G1 = 1.00 (referent)  
    G2 = 48.3-94.3    • G2 = 0.96 (0.69-1.16)  
    G3 = >94.3    • G3 = 0.64 (0.39-1.02)  
     p = 0.009  
    LTPA (MET hr/wk) Multivariate OR (95% CI) Commuting PA, men  
    G1 = < 9.2    • G1 = 1.00 (referent)  
    G2 = 9.2-13.6    • G2 = 1.11 (0.31-1.23)  
    G3 = >13.6    • G3 = 0.52 (0.27-0.87)  
    Outcome Measure: incident CC p<0.001  
    Multiple logistic regression Multivariate OR (95% CI) Commuting PA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.87 (0.42-1.52)  
        • G3 = 0.56 (0.21-0.91)  
     p = 0.007  
     Multivariate OR (95% CI) LTPA, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.17 (0.13-1.95)  
        • G3 = 0.72 (0.41-1.07)  
     p = 0.06  
     Multivariate OR (95% CI) LTPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.03 (0.41-1.59)  
        • G3 = 0.84 (0.13-2.25)  
     p = 0.15  
Boutron-Ruault et al 2001 [273] To determine which step of the adenoma-carcinoma pathway was influenced by OPA and recreational PA. • n = 480 PA assessment: Questionnaire and classified into 3 groups Number of cases: 171 A sedentary lifestyle was associated with a high risk of CC.
France   • Sex: Men and women G1 = Low Age and gender adjusted OR (95% CI), OPA  
Case control   • Age: 30-79 years G2 = Medium • G1 = 1.00 (referent)  
D & B score = 13   • Characteristics: Cases had 1stdiagnosis of colorectal adenoma, controls were polyp free. G3 = High • G2 = 1.3 (0.8-2.0)  
     • G3 = 0.5 (0.3-0.9)  
     p = 0.005  
    Outcome Measure: Incident CC   
    Multiple logistic regression Age and gender adjusted OR (95% CI), LTPA  
     • G1 = 1.00 (referent)  
     • G2 = 0.7 (0.4-1.1)  
     • G3 = 0.3 (0.2-0.5)  
     p = <0.0001  
     Age and gender adjusted OR (95% CI), Global PA  
     • G1 = 1.00 (referent)  
     • G2 = 0.8 (0.5-1.2)  
     • G3 = 0.3 (0.2-0.6)  
     p = 0.0003  
Brownson et al 1991 [274] To investigate the risks of 16 cancer types in relation to OPA. • n = 17,147 PA assessment: Medical records and classified into 3 groups: Number of cases: 1,838 OPA is inversely related to risk of CC.
   • Sex: Men   Multivariate OR (95% CI)  
USA   • Age: ≥ 20 yr OPA G1 = 1.00 (referent)  
   • Characteristics: White, working G1 = Low - Activity required <20% of time G2 = 1.2 (1.0-1.5)  
Case controll    G2 = Moderate - Activity required 20-80% of time G3 = 1.1 (1.0-1.3)  
D & B score = 15    G3 = High - Activity required >80% of time p = 0.05  
    Outcome Measure: CC   
    Maximum likelihood estimates   
Calton et al 2006 [275] To examine the relationship between PA and colon cancer risk in women. • n = 31,783 11 year follow up Number of cases: 243 Results do not support the hypothesis that PA is related to a lower incidence of CC in women.
USA   • Sex: Women PA Assessment: Questionnaire / Phone interviews for the following variables, divided into 4 or 5 groups   
Prospective cohort   • Age: 61.1 yr   Multivariate RR (95% CI), TPA  
D & B score = 12   • Characteristics: Free from cancer at baseline      • G1 = 1.00 (referent)  
        • G2 = 1.45 (0.98-2.15)  
        • G3 = 1.16 (0.77-1.75)  
        • G4 = 1.27 (0.84-1.91)  
        • G5 = 1.15 (0.76-1.75)  
     p = 0.77  
    TPA (MET h/d)   
    G1 = 34.0-48.5 Multivariate RR (95% CI), MPA  
    G2 = 48.51-54.3    • G1 = 1.00 (referent)  
    G3 = 54.31-59.0    • G2 = 1.23 (0.82-1.83)  
    G4 = 59.1-64.9    • G3 = 1.47 (0.99-2.21)  
    G5 = 65.0-98.1    • G4 = 0.94 (0.61-1.46)  
        • G5 = 1.07 (0.70-1.62)  
    MPA (h/d) p = 0.80  
    G1 = 0-3.0   
    G2 = 3.01-5.0   
    G3 = 5.01-6.70 Multivariate RR (95% CI), VPA  
    G4 = 6.71-8.14    • Q1 = 1.00 (referent)  
    G5 = 8.15-18.0    • Q2 = 1.19 (0.85-1.66)  
        • Q3 = 0.87 (0.59-1.29)  
    VPA (h/d)    • Q4 = 1.10 (0.78-1.55)  
    Q1 = 0 p = 0.80  
    Q2 = 0.1-1.0   
    Q3 = 1.1-2.0   
    Q4 = 2.1-14.0   
    Outcome Measure: Incidence of CC   
    Cox proportional HR   
Chao et al 2004 [276] To examine how the characteristics of recreational PA affect its association with colon cancer incidence among older. • n = 151,174 (70,403 men; 80,771 women) 7 year follow up Number of cases: 940 Increased amounts of time spent in recreational PA is associated with substantially lower risk of CC.
USA   • Sex: Men and women PA assessment: Questionnaire for the following variables Multivariate RR (95% CI) by recreational PA, men  
Prospective cohort   • Age: mean 63 yr      • G1 = 1.00 (referent)  
D & B score = 12   • Cancer prevention study II Nutrition Cohort      • G2 = 0.91 (0.69-1.19)  
    Recreational PA (h/wk)    • G3 = 0.72 (0.52-1.01)  
    G1 = None    • G4 = 0.86 (0.64-1.15)  
    G2 = <2    • G5 = 0.77 (0.54-1.08)  
    G3 = 2-3    • G6 = 0.58 (0.39- 0.87)  
    G4 = 4-6 p = 0.007  
    G5 = 7   
    G6 = ≥ 8 Multivariate RR (95% CI) by recreational PA, women  
    Recreational (MET h/wk)    • G1 = 1.00 (referent)  
    G1 = None    • G2 = 1.01 (0.70-1.44)  
    G2 = <7, 7-13    • G3 = 1.01 (0.68-1.49)  
    G3 = 14-23    • G4 = 0.97 (0.66-1.43)  
    G4 = 24-29    • G5 = 1.03 (0.65-1.65)  
    G5 = ≥ 30    • G6 = 0.65 (0.39-1.11)  
     p = 0.14  
    Walking (h/wk)   
    Q1 = None   
    Q2 = <4 Multivariate RR (95% CI) by recreational PA, men and women  
    Q3 = 4-6    • G1 = 1.00 (referent)  
    Q4 = ≥ 7    • G2 = 0.94 (0.75-1.16)  
        • G3 = 0.83 (0.65-1.07)  
    Walking plus other    • G4 = 0.89 (0.71-1.12)  
    activities (h/wk)    • G5 = 0.85 (0.64-1.12)  
    Q1 = None    • G6 = 0.60 (0.44-0.83)  
    Q2 = <4 p = 0.002  
    Q3 = 4-6   
    Q4 = ≥ 7 Multivariate RR (95% CI) by MET h/wk men  
    Outcome Measure: Incidence of CC    • G1 = 1.00 (referent)  
        • G2 = 0.90 (0.68-1.18)  
    Cox proportional HR    • G3 = 0.83 (0.59-1.16)  
        • G4 = 0.75 (0.55-1.01)  
        • G5 = 0.86 (0.63-1.19)  
        • G6 = 0.60 (0.41-0.87)  
     p = 0.005  
     Multivariate RR (95% CI) by MET h/wk women  
        • G1 = 1.00 (referent)  
        • G2 = 1.02 (0.71-1.46)  
        • G3 = 0.98 (0.65-1.47)  
        • G4 = 1.0 (0.68-1.47)  
        • G5 = 0.94 (0.60-1.48)  
        • G6 = 0.77 (0.48-1.24)  
     p = 0.15  
     Multivariate RR (95% CI) by MET h/wk men and women  
        • G1 = 1.00 (referent)  
        • G2 = 0.93 (0.75-1.16)  
        • G3 = 0.88 (0.68-1.13)  
        • G4 = 0.84 (0.66-1.06)  
        • G5 = 0.89 (0.68-1.15)  
        • G6 = 0.65 (0.49-0.87)  
     p = 0.002  
     Multivariate RR (95% CI) by walking, Men  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.87 (0.66-1.15)  
        • Q3 = 0.83 (0.60-1.16)  
        • Q4 = 0.88 (0.61-1.25)  
     p = 0.34  
     Multivariate RR (95% CI) by walking, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.00 (0.70-1.44)  
        • Q3 = 1.08 (0.71-1.63)  
        • Q4 = 1.18 (0.71-1.95)  
     p = 0.41  
     Multivariate RR (95% CI) by walking plus other activities, men  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.73 (0.53-1.02)  
        • Q3 = 0.85 (0.58-1.24)  
        • Q4 = 0.53 (0.36-0.78)  
     p = 0.02  
     Multivariate RR (95% CI) by walking plus other activities, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.99 (0.67-1.47)  
        • Q3 = 0.72 (0.43-1.19)  
        • Q4 = 0.59 (0.36-0.98)  
     p = 0.07  
Colbert et al 2001 [277] To examine the association between OPA and LTPA and colon cancer in male smokers. • n = 29,133 12 year follow-up Number of cases: 152 OPA is protective against CC in a dose-response manner.
USA   • Sex: Men    
Prospective cohort   • Age: 50-69 yr PA assessment: Interview for OPA and LTPA Multivariate RR (95% CI) by OPA  
D & B score = 13   • Characteristics: Smokers      • G1 = 0.61 (0.39-0.98)  
   • Alpha- Tocopherol, Beta-Carotene Cancer Prevention Study      • G2 = 1.00 (referent)  
        • G3 = 0.60 (0.34-1.04)  
    OPA    • G4 = 0.45 (0.26-0.78)  
    G1 = Non-worker p = 0.003  
    G2 = Sedentary   
    G3 = Light Multivariate RR (95% CI), by LTPA  
    G4 = Moderate    • G1 = 1.00 (referent)  
        • G2 = 0.82 (0.59-1.13)  
    LTPA   
    G1 = Sedentary   
    G2 = Active   
    Outcome Measure: incident CC   
    Cox proportional HR   
Dosemeci et al 1993 [278] To examine associations between PA and cancer sites among workers in Turkey. • n = 6,236 (3,486 cases in men and 379 cases in women; 2,127 control men and 244 control women) PA assessment: Stanford Occupational Classification code system. Number of cases: 93 Occupational EE is inversely related to risk of CC.
Turkey   • 93 cases for CC   Multivariate OR (95% CI) by total occupational EE  
Case control   • Sex: Men and women      • G1 = 1.6 (0.9-2.8)  
   • Age: not indicated Total Occupational EE (kj/min)    • G2 = 1.1 (0.6-2.0)  
D & B score = 13   • Characteristics: All hospitalized Cases: Diagnosed with CC. Controls: included subjects diagnosed as non-cancers and cancers which there is no suggestion of an association with PA. G1 = <8    • G3 = 1.0 (referent)  
    G2 = 8-12 p = 0.04  
    G3 = >12 When adjusted for socioeconomic status p = 0.03  
    Sitting time at work (h/d) Levels: Multivariate OR (95% CI) by sitting time at work  
    G1 = <2    • G1 = 1.00 (referent)  
    G2 = 2-6    • G2 = 1.5 (0.9-2.5)  
    G3 = >6    • G3 = 1.5 (0.8-3.0)  
     p = 0.03  
    Outcome Measure: Incident CC When adjusted for socioeconomic status p = 0.03  
    Maximum likelihood estimates   
Friedenreich et al 2006 [279] To investigate the role of PA in the development of colon cancer. • n = 413,044 4 year follow-up Multivariate RR (95% CI), TPA Inverse association between PA and risk of CC, particularly for right sided tumours.
   • Sex: Men and women PA assessment: modified Baecke Questionnaire    • Q1 = 1.00 (referent)  
UK   • Age: 35-70 yr      • Q2 = 0.92 (0.76-1.12)  
   • Characteristics: Free of cancer at baseline      • Q3 = 0.86 (0.70-1.04)  
Prospective cohort   • European Prospective Investigation into Nutrition and Cancer. (EPIC) TPA    • Q4 = 0.78 (0.59-1.03)  
    Q1 = Inactive p = 0.04  
D & B score = 14    Q2 = Moderately inactive Multivariate RR (95% CI), TPA and right sided CC  
    Q3 = Moderately active    • Q1 = 1.00 (referent)  
    Q4 = Active    • Q2 = 1.79 (0.59-1.06)  
    Household PA (MET-h/wk)    • Q3 = 0.64 (0.47-0.86)  
    Q1 = <19.5    • Q4 = 0.65 (0.43-1.00)  
    Q2 = 19.5-39.6 p = 0.004  
    Q3 = 39.6-73.9   
    Q4 = ≥ 73.9 Multivariate RR (95% CI), household PA and right sided CC  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.97 (0.75-1.27)  
    Outcome Measure: Incident CC    • Q3 = 0.84 (0.64-1.12)  
        • Q4 = 0.74 (0.54-1.02)  
     p = 0.05  
    Cox proportional HR   
Giovannucci et al 1995 [280] To examine the association between PA and colon cancer. • n = 47,723 6 year follow-up Multivariate RR (95% CI) A moderate level of PA was related to a substantially lower risk of CC in this cohort of middle age to elderly men.
   • Sex: Men      • G1 = 1.00 (referent)  
   • Age: 40-75 yr PA assessment: Questionnaire    • G2 = 0.73 (0.48-1.10)  
USA   • Characteristics: Health professionals      • G3 = 0.94 (0.63-1.39)  
        • G4 = 0.78 (0.51-1.20)  
Prospective cohort   • Health Professionals Follow-up Study Outcome Measure: Incidence of colon cancer    • G5 = 0.53 (0.32-0.88)  
     p = 0.03  
D & B score = 12      
    Mantel-Haeszel estimator and logistic regression   
Isomura et al 2006 [281] To examine the relationship of OPA, LTPA, commuting, housework and shopping with colorectal cancer risk. • n = 1545 (778 cases, 767 controls) PA assessment: Questionnaire and interview for the following variables    • Number of cases: 778 Adds to the evidence that PA confers decreased risk of CC, especially of distal CC in both men and women.
Japan   • Sex: Men and women   Multivariate OR (95% CI) for all CC by OPA, men  
        • G1 = 1.00 (referent)  
Case control   • Age: 20-74 yr OPA, men    • G2 = 0.9 (0.6-1.4)  
   • Characteristics: Free from cancer at baseline G1 = Sedentary    • G3 = 0.7 (0.4-1.0)  
D & B score = 12    G2 = Moderate p = 0.06  
  .   G3 = Hard   
   • Fukuoka colorectal cancer study   Multivariate OR (95% CI) for proximal  
    OPA, women CC by OPA, men  
    G1 = Sedentary    • G1 = 1.00 (referent)  
    G2 = Active    • G2 = 1.2 (0.6-2.2)  
        • G3 = 0.7 (0.4-1.4)  
    Total non-OPA, men (MET-h/wk) p = 0.45  
    G1 = 0.0 Multivariate OR (95% CI) for distal CC by OPA, men  
    G2 = 0.1-15.9    • G1 = 1.00 (referent)  
    G3 = 16.0    • G2 = 0.8 (0.4-1.4)  
        • G3 = 0.6 (0.4-1.0)  
     p = 0.047  
    Total non-OPA women (MET hr/wk)   
    G1 = 0.0   
    G2 = 0.1-15.9   
    G3 = 16.0 Multivariate OR (95% CI) for all CC by non-OPA, men  
    Moderate or hard non-OPA, men (MET hr/wk)    • G1 = 1.00 (referent)  
    G1 = 0.0    • G2 = 0.9 (0.6-1.4)  
    G2 = 0.1-14.9    • G3 = 0.8 (0.5-1.2)  
    G3 = ≥15.0 p = 0.22  
     Multivariate OR (95% CI) for proximal CC by non-OPA, men  
    Moderate or hard non-OPA, women (MET hr/wk)    • G1 = 1.00 (referent)  
    G1 = 0.0    • G2 = 1.2 (0.6-2.1)  
    G2 = 0.1-14.9    • G3 = 0.9 (0.5-1.7)  
    G3 = 15.0 p = 0.69  
    Outcome Measure: Incident CC Multivariate OR (95% CI) for distal CC by non-OPA, men  
        • G1 = 1.00 (referent)  
    Multiple logistic regression analysis    • G2 = 0.8 (0.5-1.3)  
        • G3 = 0.7 (0.4-1.1)  
     p = 0.19  
     Multivariate OR (95% CI) for all CC by non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.9 (0.5-1.5)  
        • G3 = 0.8 (0.5-1.4)  
     p = 0.45  
     Multivariate OR (95% CI) for proximal CC by non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.5 (0.7-3.3)  
        • G3 = 1.6 (0.7-3.6)  
     p = 0.41  
     Multivariate OR (95% CI) for distal CC by non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.7 (0.4-1.3)  
        • G3 = 0.6 (0.3-1.1)  
     p = 0.12  
     Multivariate OR (95% CI) for all CC by moderate or hard non-OPA, men  
        • G1 = 1.00 (referent)  
        • G2 = 0.8 (0.6-1.2)  
        • G3 = 0.8 (0.5-1.1)  
     p = 0.24  
     Multivariate OR (95% CI) for proximal CC by moderate or hard non-OPA, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.1 (0.6-2.1)  
        • G3 = 1.0 (0.6-1.8)  
     p = 0.99  
     Multivariate OR (95% CI) for distal CC by moderate or hard non-OPA, men  
        • G1 = 1.00 (referent)  
        • G2 = 0.7 (0.4-1.1)  
        • G3 = 0.7 (0.4-1.0)  
     p = 0.12  
     Multivariate OR (95% CI) for all CC by moderate or hard non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.0 (0.6-1.6),  
        • G3 = 0.8 (0.5-1.4)  
     p = 0.35  
     Multivariate OR (95% CI) for proximal CC by moderate or hard non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.3 (0.6-2.5)  
        • G3 = 1.3 (0.6-2.7)  
     p = 0.59  
     Multivariate OR (95% CI) for distal CC by moderate or hard non-OPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.8 (0.5-1.5)  
        • G3 = 0.5 (0.3-1.1)  
     p = 0.41  
Johnsen at el 2006 [282] To investigate the effects of OPA on colon cancer incidence. • n = 54,478 (28,356 men, 26,122 women) 7.6 year follow-up    • Number of cases: 140 women, 157 men No support for the hypothesis that OPA measured by MET-score may be associated with a lower risk of CC.
   • Sex: Men and women PA assessment: Questionnaire for OPA by MET score, 4 groups    • Number of dropouts: <0.8%  
Denmark   • Age: 50-64 yr   Multivariate RR (95% CI), men  
Prospective cohort   • Characteristics: Free of Cancer at baseline Q1 = Sitting    • Q1 = 1.00 (referent)  
   • Diet, Cancer and Health Study Q2 = Standing    • Q2 = 1.11 (0.69-1.77)  
    Q3 = Manual    • Q3 = 1.17 (0.77-1.79)  
D & B score = 13    Q4 = Not working    • Q4 = 0.95 (0.58-1.55)  
    Outcome Measure: Incidence of colon cancer Multivariate RR (95% CI), women  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.15 (0.68-1.93)  
        • Q3 = 1.34 (0.83-2.16)  
    Cox proportional HR    • Q4 = 0.96 (0.60-1.53)  
Larsen et al 2006 [283] To examine the relationship between PA and colorectal cancer. • n = 6,961 PA assessment: Questionnaire (scored from 2-12), divided into quartiles: Number of cases: 108 Inactivity was not a significant risk factor for advanced colonic neoplasia.
   • Sex: Men and women   RR (95% CI)  
Norway   • Age: 50-64      • Q1 = 1.00 (referent)  
   • Characteristics: No history of colorectal surgery, radiotherapy, cardiopulmonary disease, anticoagulant therapy, coronary episode. Q1 = 2-4    • Q2 = 0.61 (0.32-1.16)  
Cross-sectional evaluation within a randomized controlled trial    Q2 = 5    • Q3 = 0.75 (0.45-1.26)  
    Q3 = 6    • Q4 = 0.56 (0.34-0.92)  
    Q4 = 7-12 p = 0.04  
    Outcome Measure: Positive test for colonic neoplasia Multivariate RR (95% CI)  
D & B score = 13        • Q1 = 1.00 (referent)  
        • Q2 = 0.64 (0.33-1.25)  
        • Q3 = 0.82 (0.47-1.43)  
    Multivariate logistic regression analysis    • Q4 = 0.67 (0.39-1.16)  
     p = 0.23  
Larsson et al 2006 [284] To investigate the association between PA and colorectal cancer. • n = 45,906 7.1 year follow-up Number of cases: 309 (133 proximal, 138 distal) Results support a role of PA in reducing the risk of CC.
   • Sex: Men    
   • Age: 45-79 yr PA assessment: Questionnaire for the following variables   
Sweden   • Characteristics: Free of cancer at baseline   Multivariate HR (95% CI) by LTPA  
        • Q1 = 1.00 (referent)  
Prospective cohort        • Q2 = 0.66 (0.43-1.02)  
    LTPA (min/day)    • Q3 = 0.68 (0.46-1.01)  
    Q1 = <10    • Q4 = 0.56 (0.37-0.83)  
D & B score = 14    Q2 = 10-29 p = 0.01  
    Q3 = 30-59   
    Q4 = ≥ 60 Multivariate HR (95% CI) by home/housework PA  
    Home/housework PA (h/day)    • Q1 = 1.00 (referent)  
        • Q2 = 0.75 (0.58-0.97)  
    Q1 = none    • Q3 = 0.75 (0.58-0.97)  
    Q2 = <1    • Q4 = 0.68 (0.48-0.96)  
    Q3 = 1-2 p = 0.01  
    Q4 = ≥ 3   
    Incidence of Proximal CC(h/day) Multivariate HR (95% CI) for distal CC by LTPA  
    G1 = <1    • Q1 = 1.00 (referent)  
    G2 = 1-2   
    G3 = ≥ 3    • Q2 = 0.51 (0.28-0.93)  
        • Q3 = 0.50 (0.29-0.87)  
        • Q4 = 0.40 (0.22-0.70)  
     p = 0.01  
    Outcome Measure: Incident CC   
     Multivariate HR (95% CI) for proximal CC by home/housework PA  
    Cox proportional HR    • G1 = 1.00 (referent)  
        • G2 = 0.78 (0.53-1.14)  
        • G3 = 0.50 (0.29-0.89)  
     p = 0.02  
Lee and Paffenbarger 1994 [285] To predict cancer risk using prospective assessments of PA. • n = 17,607 26 year follow-up • Number of cases: 280 Found a trend, of borderline statistical significance toward decreasing CC risk with increasing PA.
   • Sex: Men   • Number of dropouts: 14%  
   • Age: 30-79 yr PA assessment: Questionnaire for PA level (kcal/wk)   
USA   • Characteristics: Healthy at baseline   Multivariate RR (95% CI), Model A: PA in 1962/1966 and updated in 1977  
   • Harvard College Alumni      • G1 = 1.00 (referent)  
Prospective cohort    G1 = <1000    • G2 = 1.07 (0.81-1.42)  
    G2 = 1000-2499    • G3 = 1.08 (0.81-1.46)  
    G3 = ≥ 2500 p = 0.58  
D & B score = 13      
    Outcome Measure: Incidence of fatal and non fatal CC Multivariate RR (95% CI), Model B: PA in both 1962/1966 and 1977  
        • G1 = 1.00 (referent)  
        • G2 = 0.75 (0.42-1.35)  
    Cox proportional HR    • G3 = 0.94 (0.54-1.64)  
     p = 0.76  
Lee et al 1997 [286] To investigate whether PA alters the risk of developing CC in men. • n = 20,614 10.9 year follow-up Number of cases: 217 Data does not support the hypothesis that PA is related inversely to risk of developing CC.
   • Sex: Men    
   • Age: 40-84 yrs PA assessment: Questionnaire for the following variables Multivariate RR (95% CI), frequency of  
USA   • Characteristics: Physicians, free of cancer at baseline   PA at baseline  
        • G1 = 1.00 (referent)  
Prospective cohort        • G2 = 1.1 (0.7-1.7)  
    Frequency of PA at baseline (times/week)    • G3 = 1.2 (0.8-1.6)  
   Physicians Health Study      • G4 = 1.1 (0.7-1.6)  
D & B score = 15    G1 = <1 p = 0.6  
    G2 = 1   
    G3 = 2-4 RR (95% CI), frequency of PA at baseline and 36 months  
    G4 = 5+   
        • G1 = 1.00 (referent)  
    Frequency of PA at baseline and 36 months    • G2 = 1.2 (0.5-2.7)  
    G1 = 1/<1    • G3 = 1.4 (0.9-2.3)  
    G2 = <1/1+    • G4 = 1.3 (0.9-2.0)  
    G3 = 1+/< 1   
    G4 = 1+/1+   
    Outcome Measure: Incidence of fatal and non-fatal CC   
    Cox proportional HR   
Lee et al 2007 [287] To examine the association between PA and the risk of developing CRC in Japanese men and women. • n = 65,022 6 year follow-up Number of cases: 154 proximal CC, 166 distal CC PA may prevent CC among Japanese men.
   • Sex: Men and women    
Japan   • Age: 40-69 yr   Multivariate RR (95% CI) for CC men  
   • Characteristics PA assessment: Questionnaire for PA level (median MET hr/d)    • Q1 = 1.00 (referent)  
Prospective cohort   • Ethnicity: Japanese Q1 = 28.25    • Q2 = 0.87 (0.61-1.26)  
    Q2 = 33.25    • Q3 = 0.62 (0.41-0.95)  
    Q3 = 35.25    • Q4 = 0.58 (0.39-0.87)  
D & B score = 13    Q4 = 43.75 p = 0.006  
    Outcome Measure: Incidence of CC Multivariate RR (95% CI) for proximal CC men  
    Cox proportional HR    • Q1 = 1.00 (referent)  
        • Q2 = 0.89 (0.52-1.51)  
        • Q3 = 0.44 (0.22-0.86)  
        • Q4 = 0.29 (0.14-0.60)  
     p < 0.001  
     Multivariate RR (95% CI) for distal CC Men  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.92 (0.54-1.54)  
        • Q3 = 0.75 (0.42-1.33)  
        • Q4 = 0.89 (0.53-1.51)  
     p = 0.685  
     PA level and incidence of CC women  
     Total CC  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.03 (0.65-1.64)  
        • Q3 = 0.91 (0.57-1.47)  
        • Q4 = 0.89 (0.54-1.49)  
     p = 0.610  
     Proximal CC women  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.14 (0.61-2.12)  
        • Q3 = 1.01 (0.53-1.89)  
        • Q4 = 0.55 (0.24-1.26)  
     p = 0.151  
     Distal CC women  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.09 (0.52-2.29)  
        • Q3 = 0.77 (0.34-1.74)  
        • Q4 = 1.37 (0.66-2.85)  
     p = 0.401  
Longnecker et al 1995 [288] To examine the relationship between OPA and vigorous LTPA and the risk of cancer of the right colon and rectum. • n = 242 rectal cancer and 703 controls PA assessment: Interview for vigorous LTPA and OPA (coded and self-reported), divided into groups: Number of cases: 163 The amount of time spent at vigorous LTPA was associated with a decreased risk of cancer of the right colon.
   • Sex: Men   RR (95% CI) by vigorous LTPA  
USA   • Age: ≥ 31 yr      • G1 = 1.00 (referent)  
   • Characteristics: Case: Diagnosed with adenocarcinoma of the right colon or rectum. Controls: Both community and hospital. No history of large bowel cancer.      • G2 = 0.73 (0.23-2.29)  
Case control        • G3 = 0.47 (0.16-1.36)  
    Vigorous LTPA (h/wk)    • G4 = 0.60 (0.35-1.00)  
D & B score = 14    G1 = 0 p = 0.03  
    G2 = ≤ 0.5   
    G3 = 1 Multivariate OR (95% CI) by vigorous  
    G4 = >1 LTPA  
        • G1 = 1.00 (referent)  
    Coded lifetime OPA    • G2 = 0.81 (0.26-2.54)  
    G1 = Sedentary    • G3 = 0.36 (0.11-1.14)  
    G2 = light work    • G4 = 0.57 (0.33-0.97)  
    G3 = moderate p = 0.06  
    G4 = heavy   
    Self reported lifetime Multivariate OR (95% CI) by coded lifetime OPA  
    OPA   
    G1 = Sedentary    • G1 = 1.00 (referent)  
    G2 = light work    • G2 = 0.79 (0.39-1.61)  
    G3 = more than light work    • G3 = 0.79 (0.36-1.74)  
        • G4 = 0.99 (0.30-3.22)  
     p = 0.42  
    Outcome Measure: Diagnosed with CC   
     Multivariate OR (95% CI) by self reported lifetime OPA  
    Conditional Logistic Regression    • G1 = 1.00 (referent)  
        • G2 = 0.85 (0.41-1.76)  
        • G3 = 0.68 (0.31-1.52)  
     p = 0.15  
Mai et al 2007 [289] To examine in detail the relationship between recreational PA and invasive CC among women. • n = 120,147 7 year follow-up Number of cases: 395 Modest inverse association between recreational PA and CC.
   • Sex: Women    
   • Age: 22-84 yr PA assessment: Questionnaire RR (95% CI) by MPA over past 3 years  
USA   • Characteristics: no prior history of CC      • G1 = 1.00 (referent)  
        • G2 = 0.95 (0.72-1.24)  
Prospective cohort    MPA over past 3 yrs (h/wk/yr)    • G3 = 0.78 (0.62-0.97)  
   • California Teachers Study   p = 0.02  
    G1 = 0-0.50   
D & B score = 15    G2 = 0.51-1.99 RR (95% CI) by strenuous + moderate (lifetime) PA:  
    G3 = ≥ 2.00    • G1 = 1.00 (referent)  
        • G2 = 0.79 (0.56-1.11)  
    Strenuous + Moderate (lifetime) PA (h/wk/yr)    • G3 = 0.64 (0.44-0.93)  
     p = 0.04  
    G1 = 0.0-0.50   
    G2 = 0.51-3.99   
    G3 = ≥ 4.00   
    Outcome Measure: Incidence of invasive adenocarcinoma of the colon   
    Cox proportional HR   
Martinez et al 1997 [290] To examine whether LTPA could significantly influence the risk of CC in women. • n = 89,448 6 year follow-up Number of cases: 212 Significant inverse association between LTPA and incidence of CC in women.
   • Sex: Women    
   • Age: 30-55 yr PA assessment: Questionnaire for LTPA Multivariate RR (95% CI) for all CC  
USA   • Characteristics: Nurses, free from cancer at baseline      • G1 = 1.00 (referent)  
    G1 = <2    • G2 = 0.71 (0.44-1.15)  
Prospective    G2 = 2-4    • G3 = 0.78 (0.50-1.20)  
cohort    G3 = 5-10    • G4 = 0.67 (0.42-1.07)  
    G4 = 11-21    • G5 = 0.54 (0.33-0.90)  
D & B score = 14    G5 = >21 p = 0.03  
    Outcome Measure: Incidence of CC Multivariate RR (95% CI) for distal CC  
        • G1 = 1.00 (referent)  
        • G2 = 0.92 (0.48-1.79)  
    Mantel-Haenszel Estimator and logistic regression models    • G3 = 0.81 (0.43-1.55)  
        • G4 = 0.71 (0.36-1.41)  
        • G5 = 0.31 (0.12-0.77)  
     p = 0.01  
     Multivariate RR (95% CI) for proximal  
     CC  
        • G1 = 1.00 (referent)  
        • G2 = 0.54 (0.23-1.22)  
        • G3 = 0.79 (0.40-1.56)  
        • G4 = 0.62 (0.30-1.32)  
        • G5 = 0.77 (0.38-1.58)  
     p = 0.67  
Nilsen et al 2008 [291] To study the separate associations of recreational PA with the incidence of, and mortality from cancer in the ascending, transverse, descending and sigmoid segments of the colon. • n = 59,369 17 year follow-up Number of cases: 736 Strong inverse associations between recreational PA and risk of cancer morbidity and mortality of the transverse and sigmoid colon but no association for cancer in the ascending and descending colon.
   • Sex: Men and women PA assessment: Questionnaire for frequency and duration of recreational PA HR (95% CI) by frequency of recreational PA, men  
Norway   • Age: not indicated      • G1 = 1.00 (referent)  
Prospective cohort   • Characteristics: Free from cancer at baseline      • G2 = 0.84 (0.60-1.19)  
   • Nord-Trondelag Health Study      • G3 = 0.82 (0.58-1.17)  
        • G4 = 0.81 (0.57-1.15)  
D & B score = 14    Frequency of Recreational PA (times per week)    • G5 = 0.77 (0.54-1.09)  
    G1 = none p = 0.18  
    G2 = <1 HR (95% CI) by frequency of  
    G3 = 1 recreational PA, women  
    G4 = 2-3    • G1 = 1.00 (referent)  
    G5 = ≥ 4    • G2 = 0.91 (0.66-1.25)  
        • G3 = 0.79 (0.57-1.09)  
    Duration of recreational PA (min per exercise)    • G4 = 0.66 (0.47-0.92)  
        • G5 = 0.99 (0.72-1.36)  
    G1 = none p = 0.35  
    G2 = <15   
    G3 = 15-30 HR (95% CI) by duration of recreational  
    G4 = 31-60 PA, men  
    G5 = >60    • G1 = 1.00 (referent)  
        • G2 = 1.07 (0.71-1.60)  
    Intensity of recreational PA    • G3 = 0.80 (0.57-1.12)  
        • G4 = 0.68 (0.48-0.97)  
    G1 = none    • G5 = 0.74 (0.50-1.08)  
    G2 = Low p = 0.02  
    G3 = Moderate/High HR (95% CI) by duration of recreational PA, women  
    Summary score for recreational PA    • G1 = 1.00 (referent)  
    G1 = None    • G2 = 0.85 (0.59-1.23)  
    G2 = Low    • G3 = 0.81 (0.60-1.09)  
    G3 = High    • G4 = 0.73 (0.53-1.01)  
    By subsite-specific (transverse colon, decending colon, sigmoid colon) CC    • G5 = 0.84 (0.53-1.34)  
     p = 0.10  
     HR (95% CI) by intensity of recreational PA, men  
    Levels of REC PA:   
    G1 = None    • G1 = 1.00 (referent)  
    G2 = < 1 x/wk    • G2 = 0.83 (0.62-1.12)  
    G3 = low score    • G3 = 0.74 (0.52-1.06)  
    G4 = high score p = 0.11  
    Outcome Measure: incidence of fatal and non fatal CC HR (95% CI) by intensity of recreational PA, women  
    Cox proportional HR   
        • G1 = 1.00 (referent)  
        • G2 = 0.77 (0.59-1.01)  
        • G3 = 0.89 (0.60-1.32)  
     p = 0.33  
     HR (95% CI) by summary score for recreational PA, men  
        • G1 = 1.00 (referent)  
        • G2 = 0.85 (0.62-1.16)  
        • G3 = 0.69 (0.48-0.98)  
     p = 0.06  
     HR (95% CI) by summary score for recreational PA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.86 (0.64-1.01)  
        • G3 = 0.72 (0.53-0.98)  
     p = 0.03  
     HR (95% CI) by total CC and recreational PA, incidence  
        • G1 = 1.00 (referent)  
        • G2 = 0.88 (0.70-1.12)  
        • G3 = 0.87 (0.70-*1.08)  
        • G4 = 0.73 (0.58-0.92)  
     p = 0.009  
     HR (95% CI) by subsite specific CC and recreational PA, death  
        • G1 = 1.00 (referent)  
        • G2 = 0.87 (0.64-1.18)  
        • G3 = 0.79 (0.59-1.04)  
        • G4 = 0.56 (0.41-0.78)  
     p <0.001  
     HR (95% CI) for transverse CC incidence and recreational PA  
        • G1 = 1.00 (referent)  
        • G2 = 0.75 (0.44-1.28)  
        • G3 = 0.66 (0.41-1.08)  
        • G4 = 0.44 (0.25-0.78)  
     p = 0.004  
     HR (95% CI) for transverse CC death and recreational PA  
        • G1 = 1.00 (referent)  
        • G2 = 0.73 (0.36-1.49)  
        • G3 = 0.40 (0.19-0.82)  
        • G4 = 0.33 (0.14-0.76)  
     p = 0.002  
     HR (95% CI) for sigmoid CC incidence and recreational PA  
        • G1 = 1.00 (referent)  
        • G2 = 0.88 (0.59-1.32)  
        • G3 = 0.68 (0.46-1.01)  
        • G4 = 0.48 (0.31-0.75)  
     p <0.001  
     HR (95% CI) for sigmoid CC death and recreational PA  
        • G1 = 1.00 (referent)  
        • G2 = 0.78 (0.45-1.35)  
        • G3 = 0.51 (0.30-0.87)  
        • G4 = 0.29 (0.15-0.56)  
     p <0.001  
Schnohr et al 2005 [292] To assess the association between LTPA and incidence of cancer in the general population. • n = 28,259 (15,043 men,13,216 women) 14 year follow-up    • Number of cases: 215 men, 108 women For the most active men, VPA was associated with a non-significant lower risk of CC.
Denmark    PA assessment: Questionnaire for LTPA Multivariate RR (95% CI), men  
   • Sex: Men and women G1 = Low    • G1 = 1.00 (referent)  
Prospective cohort    G2 = Moderate    • G2 = 1.08 (0.74-1.57)  
   • Age: 20-93 yr G3 = Vigorous    • G3 = 0.72 (0.47-1.11)  
D & B score = 13   • Characteristics: Free from cancer at baseline Outcome Measure: Incidence of CC p =0.06  
     Multivariate RR (95% CI), women  
   • Copenhagen Heart Study, The Copenhagen County Centre of Preventive Medicine and the Copenhagen Male Study      • G1 = 1.00 (referent)  
    Cox proportional HR    • G2 = 1.02 (0.70-1.50)  
        • G3 = 0.90 (0.56-1.46)  
     p = 0.68  
Slattery et al 1988 [293] To assess the relationship of PA and diet with the development of CC in Utah. • n = 229 cases, 384 controls PA assessment: Interview for the following variables • Number of cases: 229 PA shows an inverse relationship with incidence of CC.
USA   • Sex: Men and women   Multivariate OR (95% CI) by TPA, men  
Case control   • Age: 40-79 yr      • Q1 = 1.00 (referent)  
   • Characteristics: Case: Diagnosed with CC Controls: no history of cancer TPA    • Q2 = 1.19 (0.67-2.13)  
    Q1 = Low    • Q3 = 0.88 (0.48-1.69)  
    Q2    • Q4 = .70 (0.38-1.29)  
D & B score = 13    Q3   
    Q4 = high Multivariate OR (95% CI) by TPA, women  
    Intense PA    • Q1 = 1.00 (referent)  
    G1 = none    • Q2 = 0.97 (0.56-1.69)  
    G2 = low    • Q3 = 0.91 (0.52-1.60)  
    G3 = high    • Q4 = 0.48 (0.27-0.87)  
    Non-intense PA Multivariate OR (95% CI) by intense PA, men  
    Q1 = Low   
    Q2    • G1 = 1.00 (referent)  
    Q3    • G2 = 0.83 (0.40-1.75)  
    Q4 = high    • G3 = 0.27 (0.11-0.65)  
    Outcome Measure: Diagnosed with CC Multivariate OR (95% CI) by intense PA, women  
    Multiple logistic regression analysis    • G1 = 1.00 (referent)  
        • G2 = 0.55 (0.23-1.34)  
     Multivariate OR (95% CI) by non-intense PA, men  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.40 (0.76-2.57)  
        • Q3 = 0.93 (0.51-1.72)  
        • Q4 = 1.25 (0.68-2.29)  
     Multivariate OR (95% CI) by non-intense PA, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.09 (0.62-1.90)  
        • Q3 = 0.94 (0.53-1.66)  
        • Q4 = 0.53 (0.29-0.95)  
Slattery et al 1997 [294] To examine the relationship between weekly PA patterns (source, duration and frequency) and CC. • n = 1,993 cases, 2,410 controls PA Assessment: Interview, adapted CARDIA PA history Number of cases: 1,993 High level of leisure time VPA during the past 20 yrs was associated with a reduced risk of CC in both men and women. The same associations were not observed with leisure time MPA.
USA   • Sex: Men and women   Multivariate OR (95% CI) by recent leisure time VPA, men  
Case control   • Age: 30-79 yr Recent leisure time    • Q1 = 1.00 (referent)  
   • Characteristics: Cases: diagnosed with first primary CC. Controls: no history of CC VPA    • Q2 = 0.80 (0.64-1.01)  
    Q1 = None    • Q3 = 0.84 (0.66-1.05)  
D & B score = 14    Q2    • Q4 = 0.69 (0.55-0.87)  
    Q3   
    Q4 = High Multivariate OR (95% CI) by recent leisure time VPA, women The greatest inverse association was observed when activities were performed for longer periods of time per session.
   The Three Centered Diet, Activity and Lifestyle Colon Cancer Study Leisure time VPA    • Q1 = 1.00 (referent)  
    Q1 = Low    • Q2 = 0.79 (0.61-1.02)  
    Q2    • Q3 = 0.83 (0.64-1.07)  
    Q3    • Q4 = 0.86 (0.67-1.10)  
    Q4 = High   
    Current PA (min) Multivariate OR (95% CI) by leisure time VPA, men  
    G1 = <30   
    G2 = 30-60    • Q1 = 1.00 (referent)  
    G3 = ≥ 60    • Q2 = 0.97 (0.76-1.25)  
        • Q3 = 0.86 (0.67-1.09)  
    LTPA (ranked by time per session)    • Q4 = 0.61 (0.47-0.79)  
    Q1 = None Multivariate OR (95% CI) by leisure time VPA, women  
    Q2 = Low - <30 min   
    Q3 = moderate - 30-60 min    • Q1 = 1.00 (referent)  
    Q4 = high ->60 min    • Q2 = 0.75 (0.59-0.95)  
        • Q3 = 0.68 (0.53-0.87)  
    Number of activity session per week    • Q4 = 0.63 (0.48-0.83)  
    G1 = None Multivariate OR (95% CI) by current MPA time per week  
    G2 = 1   
    G3 = 2-4    • Q1 = 1.00 (referent)  
    G4 = 5-7    • Q2 = 1.00 (0.83-1.21)  
    G5 = >7    • Q3 = 0.90 (0.76-1.07)  
        • Q4 = 0.92 (0.77-1.10)  
    Outcome Measure: Diagnosed with CC Multivariate OR (95% CI) by current VPA time per week  
    Unconditional regression models    • Q1 = 1.00 (referent)  
        • Q2 = 0.90 (0.73-1.12)  
        • Q3 = 0.89 (0.71-1.10)  
        • Q4 = 0.83 (0.69-0.98)  
     Multivariate OR (95% CI) by leisure time MPA time per session  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.20 (0.91-1.59)  
        • Q3 = 1.09 (0.83-1.42)  
        • Q4 = 1.08 (0.82-1.42)  
     Multivariate OR (95% CI) by leisure time VPA time per session  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.86 (0.74-0.99)  
        • Q3 = 0.76 (0.64-0.90)  
        • Q4 = 0.68 (0.52-0.87)  
     Multivariate OR (95% CI) by number of MPA sessions/wk  
        • G1 = 1.00 (referent)  
        • G2 = 1.02 (0.79-1.30)  
        • G3 = 0.86 (0.72-1.02)  
        • G4 = 0.91 (0.81-1.14)  
        • G5 = 1.02 (0.82-1.27)  
     Multivariate OR (95% CI) by number of VPA sessions/wk  
        • G1 = 1.00 (referent)  
        • G2 = 0.72 (0.56-0.92)  
        • G3 = 0.87 (0.73-1.03)  
        • G4 = 1.00 (0.81-1.25)  
        • G5 = 0.84 (0.61-1.15)  
Slattery et al 1997 [295] To determine how physical inactivity interacts with other components of energy balance in determining risk of CC. • n = 1,993 cases, 2,410 controls PA Assessment: Interview for lifetime VPA (PA index) Number of cases: 1,993 These results support previous findings that physical inactiity is associated with an increased risk of developing CC.
USA   • Sex: Men and women Q1 = 10-12 Multivariate OR (95% CI), men  
   • Age: 30-79 yr Q2 = 7-9    • Q1 = 1.00 (referent)  
   • Characteristics: Cases: diagnosed with first primary CC. Controls: no history of CC Q3 = 4-6    • Q2 = 1.60 (1.11-1.75)  
Case control   • The Three Centered Diet, Activity and Lifestyle Colon Cancer Study Q4 = <4    • Q3 = 1.59 (1.26-2.01)  
D & B score = 14        • Q4 = 1.63 (1.26-2.12)  
    Outcome Measure: Diagnosed with CC Multivariate OR (95% CI), women  
        • Q1 = 1.00  
        • Q2 = 1.14 (0.86-1.52)  
    Unconditional regression models    • Q3 = 1.13 (0.85-1.49  
        • Q4 = 1.59 (1.21-2.10)  
Takahashi et al 2007 [296] To investigate the association between time spent walking each day and the risk of CRC. • n = 20,519 men, 21,469 women 7 year follow-up    • Number of cases: 101 Time spent walking per day was associated with a lower risk of colon cancer in men but not in women.
   • Sex: Men and women PA assessment: Questionnaire for time spent walking (h/day)    • Number of dropouts: 3.5%  
Japan   • Age: 40-64 yr   Multivariate RR (95% CI), men  
   • Characteristics: Free from cancer at baseline      • G1 = 1.00 (referent)  
Prospective cohort    G1 = <0.5    • G2 = 0.72 (0.43-1.21)  
    G2 = 0.5-1    • G3 = 0.38 (0.22-0.64)  
    G3 = >1 p < 0.001  
D & B score = 12    Outcome Measure: Incidence of CC Time spent walking and incidence of CC  
     Multivariate RR (95% CI), women  
    Cox proportional HR    • G1 = 1.00  
        • G2 = 2.68 (0.94-7.68)  
        • G3 = 1.79 (0.64-4.96)  
     p = 0.42  
Tang et al 1999 [297] To investigate the association between PA, water intake and risk of CRC in a hospital based case controlled study. • n = 163 cases, 163 controls PA assessment: Interview    • Number of cases: 163 Found a negative association between LTPA and the risk of CC among men.
   • Sex: Men and women   Multivariate RR (95% CI), men  
Taiwan    LTPA METs    • G1 = 1.00 (referent)  
   • Age: 33-80 yr G1 = Sedentary    • G2 = 2.22 (0.68-7.21)  
Case control   • Characteristics: Cases: Hospital patients diagnosed with colorectal cancer Controls: Hospital patients in hospital for other reasons, free of CRC. G2 = Moderate (< 20 MET)    • G3 = 0.19 (0.05-0.77)  
D & B score = 14    G3 = Active (≥20 MET) p = 0.03  
     Multivariate RR (95% CI), women  
    Outcome Measure: Diagnosis of CC    • G1 = 1.00 (referent)  
        • G2 = 0.52 (0.13-2.03)  
        • G3 = 0.63 (0.18-2.18)  
    Conditional logistic regression analysis p = 0.48  
Tavani et al 1999 [298] To investigate the relationship between PA and risk of CC in both sexes at different ages. • n = 5,379 (1,225 cases and 4,154 controls) PA assessment: Questionnaire on activity at work and during leisure time    • Number of cases: 537 women, 688 men The study confirms that OPA is protective against CC.
Italy   • Sex: Men and women   Multivariate OR (95% CI) for CC by OPA at age 15-19 yr, men  
Case control   • Age: 19-74 yr G1 = Highest    • G1 = 1.00 (referent)  
    G2    • G2 = 0.89 (0.64-1.23)  
D & B score = 13    G3    • G3 = 0.72 (0.54-0.97)  
    G4    • G4 = 0.54 (0.40-0.74)  
    G5 = Lowest    • G5 = 0.47 (0.31-0.71)  
     p < 0.01  
    OPA at 30-39 yrs old   
    Q1 = Highest Multivariate OR (95% CI) for CC by OPA at age 15-19 yr, women  
    Q2    • G1 = 1.00 (referent)  
    Q3    • G2 = 0.73 (0.55-0.96)  
    Q4 = Lowest    • G3 = 0.91 (0.69-1.21)  
    Outcome Measure: Diagnosis of CC    • G4 = 0.62 (0.44-0.89)  
    Unconditional multiple Logistic Regression p < 0.05  
     Multivariate OR (95% CI) for CC by OPA at age 30-39 yr, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.01 (0.75-1.37)  
        • G3 = 0.79 (0.59-1.06)  
        • G4 = 0.71 (0.52-0.97)  
        • G5 = 0.64 (0.44-0.93)  
     p < 0.01  
     Multivariate OR (95% CI) for CC by OPA at age 30-39 yr, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.65 (0.46-0.93)  
        • G3 = 0.57 (0.41-0.79)  
        • G4 = 0.49 (0.33-0.72)  
     p < 0.01  
     Multivariate OR (95% CI) for CC by OPA at age 50-59 yr, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.06 (0.78-1.43)  
        • G3 = 0.85 (0.63-1.14)  
        • G4 = 0.68 (0.49-0.95)  
        • G5 = 0.69 (0.45-1.05)  
     p < 0.01  
     Multivariate OR (95% CI) for CC by OPA at age 50-59 yr, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.69 (0.47-1.00)  
        • G3 = 0.68 (0.46-1.00)  
        • G4 = 0.75 (0.47-1.20)  
     p = > 0.05  
     Multivariate OR (95% CI) for ascending CC by OPA at age 30-39 yr No significant associations for men or women  
     Multivariate OR (95% CI) for transverse and descending CC by OPA at age 30-39 yr, men  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.92 (0.51-1.67)  
        • Q3 = 0.76 (0.43-1.37)  
        • Q4 = 0.46 (0.24-0.87)  
     p < 0.05  
     Multivariate OR (95% CI) for transverse and descending CC by OPA at age 30-39 yr, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.51 (0.23-1.10)  
        • Q3 = 0.39 (0.19-0.80)  
        • Q4 = 0.29 (0.12-0.71)  
     p < 0.01  
     Multivariate OR (95% CI) for sigmoid CC by OPA at age 30-39 yr, men  
        • Q1 = 1.00 (referent)  
        • Q2 = 1.02 (0.65-1.57)  
        • Q3 = 0.78 (0.51-1.20)  
        • Q4 = 0.54 (0.34-0.85)  
     p < 0.01  
     Multivariate OR (95% CI) for sigmoid CC by OPA at age 30-39 yr, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.62 (0.36-1.05)  
        • Q3 = 0.71 (0.44-1.15)  
        • Q4 = 0.58 (0.32-1.03)  
     p > 0.05  
Thune et al 1996 [299] To examine the association between self-reported OPA and LTPA and the subsequent risk of CC. • n = 81,516 (53,242 men, 28,274 women) 16.3 year follow up Number of cases: 236 men, 99 women An inverse dose-response relationship between TPA and risk of CC was observed in women. In men this inverse dose-response was found only for those 45 yrs or older at study entry.
    PA assessment: Questionnaire for TPA (OPA plus recreational PA (combined) Multivariate RR (95% CI) for total CC, men  
Norway   • Sex: Men and women G1 = Sedentary    • G1 = 1.00 (referent)  
Prospective cohort   • Age: 20-49 yr G2 = Moderate    • G2 = 1.18 (0.76-1.82)  
   • Characteristics: Free from cancer at baseline G3 = Active    • G3 = 0.97 (0.63-1.50)  
D & B score = 14     p = 0.49  
     Multivariate RR (95% CI) for total CC, women  
    Outcome Measure: Incidence of CC    • G1 = 1.00 (referent)  
    Cox proportional HR    • G2 = 0.97 (0.33-2.77)  
        • G3 = 0.63 (0.39-1.04)  
     p = 0.04  
     Multivariate RR (95% CI) for proximal CC, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.16 (0.57-2.34)  
        • G3 = 0.96 (0.47-1.93)  
     p = 0.64  
     Multivariate RR (95% CI) for proximal CC, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.22 (0.51-2.94)  
        • G3 = 0.62 (0.30-1.28)  
     p = 0.10  
     Multivariate RR (95% CI) for distal CC, men  
        • G1 = 1.00 (referent)  
        • G2 = 1.29 (0.72-2.33)  
        • G3 = 0.99 (0.55-1.80)  
     p = 0.53  
     Multivariate RR (95% CI) for distal CC, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.84 (0.32-2.17)  
        • G3 = 0.61 (0.30-1.23)  
     p = 0.15  
     Multivariate RR (95% CI) for total CC, men < 45 yrs at entry  
        • G1 = 1.00 (referent)  
        • G2 = 2.02 (0.78-5.21)  
        • G3 = 2.23 (0.88-5.66)  
     p = 0.13  
     Multivariate RR (95% CI) for total CC, women < 45 yrs at entry  
        • G1 = 1.00 (referent)  
        • G2 = 0.96 (0.39-2.40)  
        • G3 = 0.62 (0.31-1.23)  
     p = 0.13  
     Multivariate RR (95% CI) for total CC, men ≥ 45 yrs at entry  
        • G1 = 1.00 (referent)  
        • G2 = 0.96 (0.59-1.58)  
        • G3 = 0.66 (0.40-1.10)  
     p = 0.04  
     Multivariate RR (95% CI) for total CC, women ≥ 45 yrs at entry  
        • G1 = 1.00 (referent)  
        • G2 = 0.99 (0.41-2.39)  
        • G3 = 0.66 (0.33-1.33)  
     p = 0.19  
Vena et al 1985 [300] To assess the relationship between lifetime OPA and the risk of CC. • n = 1,641 (210 cases, 1,431 control) PA assessment: Questionnaire • Number of cases: 210 CC risk increased with increasing amount and proportion of time in jobs involving only sedentary or light work.
USA   • Sex: Men Number of work years in jobs with sedentary or light work (yr) OR (95% CI) by number of work years in jobs with sedentary or light work  
Case control   • Age: 30-79 yr G1 = None    • G1 = 1.00 (referent)  
   • Characteristics: Cases: admitted to hospital. Diagnosis of CC Controls: Admitted to hospital. Diagnosed with non-neoplastic non-digestive diseases G2 = 1-20    • G2 = 1.49  
D & B score = 15    G3 = >20    • G3 = 1.97  
     OR (95% CI) by proportion of years in jobs with sedentary or light work  
    Proportion of years in jobs with sedentary or light work    • G1 = 1.00 (referent)  
        • G2 = 1.53  
        • G3 = 1.58  
    G1 = None    • G4 = 2.10  
    G2 = 0.01-0.50   
    G3 = 0.41-0.99 OR (95% CI) by proportion of life in jobs with sedentary or light work  
    G4 = 1.00 (referent)   
        • G1 = 1.00 (referent)  
    Proportion of life in jobs with sedentary or light work    • G2 = 1.66  
        • G3 = 1.83  
    G1 = None   
    G2 = 0.01-0.40   
    G3 = 0.41-1.00   
    Outcome Measure: diagnosed with CC   
    Multiple logistic regression   
Vetter et al 1992 [301] To investigate the influence of OPA on the risk of CC in a developing country. • n = 87 men cases, 13 women cases, 371 controls PA assessment: Questionnaire Job title and industry names Number of cases: 87 men, 13 women This study presents a weak inverse association between CC and PA.
USA   • Sex: Men and women   OR (95% CI) Sitting time and CC Only 2 of the 4 measures of activity showed evidence of an increased CC risk for sedentary jobs (time spent sitting and occupational EE) though neither was statistically significant.
Case control   • Age: 14-97 yr Levels (Sitting time, energy expenditure    • G1 = 1.00 (referent)  
D & B score = 11   • Characteristics: Cases: Diagnosed with CC Controls: cancer cases other then colon, rectum and lung cancer. G1 = High    • G2 = 1.0 (0.5-2.0)  
    G2 = Moderate    • G3 = 1.5 (0.7-2.9)  
    G3 = Sedentary p = 0.145  
    Outcome Measure: Diagnosed with CC OR (95% CI) Energy Expenditure and CC  
        • G1 = 1.00 (referent)  
        • G2 = 1.5 (0.7-3.3)  
        • G3 = 1.6 (0.8-3.6)  
     p = 0.143  
White et al 1996 [302] To assess the relationship between PA and CC among men and women. • n = 871 (251 men, 193 women cases. 233 men & 194 women controls) PA assessment: Phone interview • Number of cases: 251 men & 193 women The results of this study show modest support that recreational PA is associated with a reduced risk of CC.
USA    Total PA (episodes/wk) RR (95% CI) by total PA, men  
    G1 = 0    • G1 = 1.00 (referent)  
Case control   • Sex: Men and women G2 = <1    • G2 = 0.81 (0.45-1.44)  
    G3 = 1-<2    • G3 = 0.53 (0.30-0.94)  
D & B score = 14   • Age: 30-62 yr G4 = 2-< 4    • G4 = 0.57 (0.33-1.00)  
   • Characteristics: Cases: Diagnosed with CC, no previous history or CC or inflammatory bowel G5 = ≥ 4    • G5 = 0.57 (0.40-1.11)  
    Moderate-high intensity PA (epsiodes/wk) p = 0.03  
     RR (95% CI) by total PA, women  
    G1 = 0    • G1 = 1.00 (referent)  
    G2 = <1    • G2 = 1.17 (0.57-2.40)  
    G3 = 1-<2    • G3 = 1.27 (0.65-2.45)  
   Controls: No history of CC or inflammatory bowel G4 = ≥ 2    • G4 = 0.59 (0.34-1.04)  
        • G5 = 1.09 (0.61-1.97)  
    High intensity PA (episodes/wk) p = 0.52  
    G1 = 0 RR (95% CI) by total PA, men and women  
    G2 = <1    • G1 = 1.00 (referent)  
    G3 = ≥ 1    • G2 = 0.94 (0.60-1.47)  
    METS/wk    • G3 = 0.77 (0.50-1.19)  
    Q1 = 0    • G4 = 0.57 (0.39-0.85)  
    Q2 = <7.30   
    Q3 = 7.30-17.88    • G5 = 0.83 (0.57-1.22)  
    Q4 = ≥ 17.88 p = 0.04  
    Outcome Measure: Diagnosed with CC RR (95% CI) by moderate-high intensity PA, men  
        • G1 = 1.00 (referent)  
    Unconditional logistic regression    • G2 = 0.84 (0.49-1.43)  
        • Q3 = 0.75 (0.42-1.36)  
        • Q4 = 0.66 (0.41-1.05)  
     p = 0.07  
     RR (95% CI) by moderate-high intensity PA, women  
        • G1 = 1.00 (referent)  
        • G2 = 1.07 (0.58-1.97)  
        • G3 = 1.00 (0.51-1.98)  
        • G4 = 0.74 (0.42-1.29)  
     p = 0.37  
     RR (95% CI) by moderate-high intensity PA, men and women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.93 (0.62-1.39)  
        • Q3 = 0.86 (0.55-1.34)  
        • Q4 = 0.70 (0.49-1.00)  
     p = 0.05  
     RR (95% CI) by high intensity PA, men  
        • G1 = 1.00 (referent)  
        • G2 = 0.85 (0.48-1.52)  
        • G3 = 0.57 (0.35-0.92)  
     p = 0.02  
     RR (95% CI) by high intensity PA, Women  
        • G1 = 1.00 (referent)  
        • G2 = 1.02 (0.51-2.04)  
        • G3 = 0.74 (0.43-1.28)  
     p = 0.31  
     RR (95% CI) by high intensity PA, men and women  
        • G1 = 1.00 (referent)  
        • G2 = 0.93 (0.59-1.44)  
        • G3 = 0.64 (0.45-0.92)  
     p = 0.02  
     RR (95% CI) by METs/wk, men  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.64 (0.38-1.07)  
        • Q3 = 0.59 (0.37-0.96)  
        • Q4 = 0.69 (0.42-1.13)  
     p = 0.05  
     RR (95% CI) by METs/wk, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.87 (0.51-1.49)  
        • Q3 = 1.20 (0.69-2.08)  
        • Q4 = 0.74 (0.41-1.34)  
     p = 0.62  
     RR (95% CI) by METs/wk, women  
        • Q1 = 1.00 (referent)  
        • Q2 = 0.73 (0.50-1.06)  
        • Q3 = 0.80 (0.56-1.16)  
        • Q4 = 0.73 (0.50-1.06)  
     p = 0.08  
Wolin et al 2007 [303] To assess the relationship between PA and risk of CC in women. • n = 79,295 16 year follow-up Number of cases: 547 (245 distal, 302 proximal) Number of dropouts: 10% A significant inverse association exists between PA, including moderate intensity, such as walking, and risk of CC in women that is more pronounced for distal tumours.
   • Sex: Women    
   • Age: 40-65 yr PA assessment: Questionnaire   
USA   • Characteristics: Nurses, no history of CC, ulcerative colitis and Crohn's disease    
Prospective cohort    Level of PA Multivariate RR (95% CI) for distal CC by level of PA  
    G1 = <2    • G1 = 1.00 (referent)  
    G2 = 2.1-4.5    • G2 = 0.93 (0.64-1.36)  
D & B score = 14    G3 = 4.6-10.3    • G3 = 0.99 (0.68-1.44)  
   Nurses' Health Study G4 = 10.4 - 21.4    • G4 = 0.87 (0.59-1.29  
    G5 = ≥ 21.5    • G5 = 0.54 (0.34-0.84)  
    MPA or VPA (hr/wk) p = 0.004  
    G1 = 0 Multivariate RR (95% CI) for proximal CC by level of PA not significant p = 0.77  
    G2 = <1   
    G3 = 1-1.9   
    G4 = 2-3.9   
    G5 = ≥ 4 Multivariate RR (95% CI) for all CC by MPA or VPA  
    Outcome Measure: Fatal and non fatal CC    • G1 = 1.00 (referent)  
        • G2 = 0.85, (0.64-1.14)  
    Cox proportional HR    • G3 = 0.74 (0.53-1.04)  
        • G4 = 0.56 (0.33-0.94)  
     p = 0.01  
     Multivariate RR (95% CI) for distal CC by MPA or VPA  
        • G1 = 1.00 (referent)  
        • G2 = 1.10 (0.73-1.66)  
        • G3 = 0.63 (0.36-1.10)  
        • G4 = 0.51 (0.22-1.17)  
     p = 0.04  
     Multivariate RR (95% CI) for proximal CC by MPA or VPA not significant p = 0.12  
Zhang et al 2006 [304] To examine the relationship between LTPA and OPA and the risk of CC by anatomic site and to evaluate their joint effect on the risk of CC. • n = 585 cases 2,172 controls PA assessment: Questionnaire for the following variables Number of cases: 585 Found a significant inverse association between reported LTPA and risk of CC with a slightly stronger association for the right colon than the left in both men and women.
USA   • Sex: Men and women   Multivariate OR (95% CI) by moderate- strenuous LTPA, men and women  
   • Age: 40-85 yr Moderate-Strenuous LTPA    • G1 = 1.00 (referent)  
Case control   • Characteristics: Case: diagnosed with CC Control: no history of CC. G1 = <1 month    • G2 = 0.7 (0.5-1.1)  
    G2 = 1-4 months    • G3 = 0.6 (0.4-0.8)  
D & B score = 15    G3 = ≥ 2 weeks p = 0.003  
     Multivariate OR (95% CI) by moderate- strenuous LTPA, men The joint effect of OPA and LTPA suggested that the risk was lowest for those with high OPA and non-OPA.
        • G1 = 1.00 (referent)  
    Outcome Measure: CC    • G2 = 0.9 (0.5-1.7)  
        • G3 = 0.5 (0.3-0.9)  
    Unconditional logistic regression models p = 0.02  
     Multivariate OR (95% CI) by moderate-strenuous LTPA, women  
        • G1 = 1.00 (referent)  
        • G3 = 0.5 (0.3-1.0)  
        • G3 = 0.6 (0.4-0.9)  
     p = 0.02  
     Multivariate OR (95% CI) by moderate-strenuous LTPA, men and women  
        • G1 = 1.00 (referent)  
        • G2 = 0.7 (0.5-1.1)  
        • G3 = 0.8 (0.6-1.1)  
     p = 0.53  
     Multivariate OR (95% CI) by moderate-strenuous LTPA, men  
        • G1 = 1.00 (referent)  
        • G2 = 0.9 (0.5-1.5)  
        • G3 = 0.8 (0.6-1.2)  
     p = 0.55  
     Multivariate OR (95% CI) by moderate- strenuous LTPA, women  
        • G1 = 1.00 (referent)  
        • G2 = 0.6 (0.3-1.1)  
        • G3 = 0.8 (0.5-1.2)  
     p = 0.62  
     Multivariate OR (95% CI) by moderate- strenuous LTPA and OPA, OPA-Low  
        • G1 = 1.00 (referent)  
        • G2 = 0.5 (0.3-0.9)  
        • G3 = 0.8 (0.5-1.2)  
     p = 0.41  
     Multivariate OR (95% CI) by moderate-strenuous LTPA and OPA, OPA-Medium  
        • G1 = 0.7 (0.5-1.1)  
        • G2 = 0.7 (0.4-1.3)  
        • G3 = 0.5 (0.3-0.8)  
     p = 0.04  
     Multivariate OR (95% CI) by moderate-strenuous LTPA and OPA, OPA-High  
        • G1 = 0.9 (0.5-1.6)  
        • G2 = 0.6 (0.3-1.3)  
        • G3 = 0.5 (0.3-0.8)  
  1. D & B score, Downs and Black quality score; YR, years; PA, physical activity; OPA, occupational physical activity; kJ/min, kilojoules per minute; G, groups; MET, metabolic equivalent; HR, hazard ratio; RR, risk ratio; OR, odds ratio; 95% CI, confidence interval; LTPA, leisure-time physical activity; CC, colon cancer; TPA, total physical activity; MDA, moderate physical activity; h/d, hours per day; VPA, vigorous physical activity; h/wk, hours per week.