Table 4.

Colorectal cancer risk by ethnicity and quartiles of pack-years of all tobacco products and of filtered and non-filtered cigarettes

Q1*
Q2
Q3
Q4
Ptrend
nOR (95% CI)nOR (95% CI)nOR (95% CI)nOR (95% CI)
Japanese (1,018 case-control pairs)
    All tobacco108/961.09 (0.78-1.51)141/1210.89 (0.65-1.21)128/1651.34 (0.99-1.82)135/1841.27 (0.94-1.74)0.06
    Filtered cigarettes95/991.22 (0.85-1.75)97/1111.09 (0.77-1.54)116/1351.12 (0.80-1.57)104/1120.95 (0.68-1.34)0.58
    Non-filtered cigarettes89/730.83 (0.57-1.21)77/750.97 (0.64-1.49)91/1021.15 (0.78-1.69)63/1231.96 (1.29-2.98)0.004
Caucasian (485 case-control pairs)
    All tobacco76/631.17 (0.77-1.78)64/771.50 (0.97-2.31)70/721.47 (0.94-2.28)79/1231.92 (1.27-2.92)0.003
    Filtered cigarettes61/440.74 (0.46-1.21)56/550.95 (0.58-1.54)37/461.35 (0.79-2.31)54/861.53 (0.97-2.40)0.04
    Non-filtered cigarettes46/421.06 (0.64-1.77)48/401.01 (0.59-1.73)39/541.54 (0.92-2.58)63/881.42 (0.90-2.24)0.09
Native Hawaiian (191 case-control pairs)
    All tobacco30/220.88 (0.40-1.90)32/321.08 (0.55-2.15)33/180.60 (0.28-1.26)24/511.99 (0.97-4.07)0.07
    Filtered cigarettes23/200.94 (0.41-2.14)33/230.62 (0.30-1.29)21/251.06 (0.48-2.33)26/321.01 (0.50-2.04)0.77
    Non-filtered cigarettes23/190.94 (0.40-2.18)17/150.91 (0.34-2.42)10/171.92 (0.61-6.11)13/242.33 (0.93-5.83)0.05
  • NOTE: OR and 95% CI are estimated by conditional logistic regression, matched on age and sex, and adjusted for family history of colorectal cancer, body mass index 5 y ago, lifetime hours in recreational activities as well as egg, total calcium, non-starch polysaccharides from vegetables, methionine, and alcohol intake. Two separate models were run in each ethnicity, both with never smokers as the reference category: one model included indicator variables for each quartile of pack-years of all tobacco products, and the other model included indicator variables for each quartile of pack-years for each type of cigarettes (filtered and non-filtered) and was further adjusted for pack-years of cigars and pipes (continuous).

  • * Q1, 1st quartile; Q2, 2nd quartile; Q3, 3rd quartile; Q4, 4th quartile. Based on controls who smoked, the quartile cut points (25th-75th percentile) for total pack-years are as follows: >0-9.8, >9.8-24.6, >24.6-44, and >44; for pack-years of filtered cigarettes: >0-9.5, >9.5-21, >21-38, and >38; for pack-years of non-filtered cigarettes: >0-4, >4-10, >10-22, and >22.

  • Ptrend is estimated by fitting the medians of each quartile as a continuous variable in the multivariate model.

  • Number of controls/number of cases (never smokers: 506/452, 196/150 and 72/68 for Japanese, Caucasians, and Native Hawaiians, respectively).