Table 2.

Smoking and CRC risk according to sex, MMR gene mutated, attained age, birth cohort, and ascertainment source in MMR gene mutation carriers

CharacteristicTotal cohortSmoking status*
Former smokersCurrent smokers
Person-yearsNo. of CRC casesPerson-yearsNo. of CRC casesHR (95% CI)Person-yearsNo. of CRC casesHR (95% CI)
Total cohort34,129426
Sex
    MaleUnweighted14,3202025,575660.69 (0.52-0.92)3,250561.56 (1.14-2.12)
Weighted0.44 (0.23-0.83)1.56 (0.82-2.97)
TVC0.43 (0.23-0.79)2.0 (1.07-3.76)
    FemaleUnweighted19,8092245,061520.85 (0.64-1.11)3,790511.45 (1.01-2.08)
Weighted0.61 (0.38-0.99)1.63 (0.85-3.13)
TVC0.6 (0.37-0.97)1.54 (0.8-2.98)
Ascertainment source
    PopulationUnweighted5,520912,020300.75 (0.51-1.10)954201.59 (0.95-2.67)
Weighted0.61 (0.27-1.44)3.91 (1.39-10.99)
TVC0.62 (0.27-1.44)3.91 (1.39-10.99)
    ClinicUnweighted28,6093358,616880.74 (0.57-0.95)6,086871.43 (1.06-1.92)
Weighted0.51 (0.32-0.83)1.43 (0.86-2.38)
TVC0.49 (0.30-0.8)1.5 (0.9-2.51)
MMR gene mutation
    MLH1Unweighted13,0301803,632440.80 (0.59-1.10)2,796471.71 (1.24-2.35)
Weighted0.55 (0.30-0.99)1.59 (0.88-2.88)
TVC0.5 (0.27-0.94)
    MSH2Unweighted17,9742255,660630.68 (0.50-0.94)3,749561.30 (0.88-1.94)
Weighted0.48 (0.27-0.85)1.50 (0.76-2.96)
TVC0.47 (0.27-0.84)1.4 (0.71-2.77)
    MSH6Unweighted3,125211,344111.12 (0.34-3.70)49541.80 (0.56-5.74)
Weighted3.19 (0.68-14.9)6.02 (1.40-25.87)
TVC3.18 (0.68-14.9)6.02 (1.4-25.87)
Age§, y
    ≤50Unweighted21,5993055,593720.78 (0.60-1.02)5,270871.36 (1.01-1.82)
Weighted0.67 (0.39-1.13)1.50 (0.86-2.62)
TVC0.66 (0.38-1.15)1.57 (0.91-2.69)
    >50Unweighted12,5301215,043460.81 (0.55-1.22)1,770201.28 (0.79-2.08)
Weighted0.58 (0.27-1.24)1.57 (0.61-4.03)
TVC0.55 (0.26-1.17)1.61 (0.62-4.17)
Birth cohort
    Before 1940Unweighted9,3591213,035340.69 (0.45-1.06)1,779291.34 (0.80-2.22)
Weighted0.44 (0.20-1.01)1.69 (0.81-3.51)
TVC0.59 (0.27-1.32)2.08 (0.99-4.33)
    1940-1949Unweighted8,5811143,072400.83 (0.57-1.23)1,629241.45 (0.82-2.58)
Weighted0.56 (0.23-1.39)1.42 (0.46-4.39)
TVC0.53 (0.22-1.27)1,48 (0.45-4.81)
    1950-1959Unweighted9,3491152,733300.82 (0.55-1.23)2,077291.45 (0.95-2.21)
Weighted0.44 (0.20-0.97)1.11 (0.48-2.58)
TVC0.42 (0.2-0.9)1.13 (0.45-2.85)
    1960 or laterUnweighted6,840761,796140.74 (0.40-1.38)1,555251.96 (1.24-3.08)
Weighted0.56 (0.22-1.41)2.47 (1.08-5.65)
TVC0.67 (0.25-1.74)2.98 (1.34-6.62)
  • *Reference group “never smokers”

  • HR adjusted for each of the other variables in the table.

  • Smoking analyzed as time-varying covariate.

  • §Age at CRC onset for cases or age at censoring for the unaffected.