| Study | Number of cases | Time in relation to diagnosis | Relative risk (95% confidence interval) * | |
|---|---|---|---|---|
| Former smokers | Current smokers | |||
| Case-control | ||||
| Harries et al. 1982 | 230 | A ** | Increased risk | Decreased risk |
| Jick and Walker 1983 | 239 | A | 1.2 (0.8-1.8) | 0.3 (0.2-0.4) |
| Gyde et al. 1984 | 74 31¶ | A A | Decreased
risk§
Decreased risk§ | Decreased risk
>§<§
Decreased risk >§<§ |
| Logan et al. 1984 ¶¶ | 120 64¶ |
D***
D | NR§§§
NR | Decreased
risk¶¶¶
Decreased risk¶¶¶ |
| Thornton et al. 1985 | 30 | D | Increased risk >§<§ | Decreased risk >§<§ |
| Burns 1986 | 63 | A | Increased risk >§<§ | Decreased risk¶¶¶ |
| Benoni and Nilsson 1987 ¶¶ | 173 80¶ | D D | 1.6 1.8 | 0.3
>§<§
0.3 >§<§ |
| Boyko et al. 1987 ¶¶ | 212 | D | 1.9 (1.1-3.5) | 0.6 (0.4-1.0) |
| Franceschi et al. 1987 | 124 49¶ | D D | 2.7 (1.5-4.9) 2.6 (1.0-7.2) | 0.5 (0.3-1.0) 1.1 (0.4-2.2) |
| Tobin et al. 1987 | 143 81¶ | D D | 1.5 (0.8-2.8) NR | 0.2
(0.1-0.3)¶¶¶
Decreased risk |
| Lindberg et al. 1988 ¶¶ | 258 | D | 2.3 (1.4-3.9) | 0.7 (0.4-1.0) |
| Lorusso et al. 1989 | 84 | D | 3.0 (0.9-10.3) | Decreased risk¶¶¶ |
| Persson et al. 1990 ¶¶ | 145 63 | D D | 2.2 (0.9-5.0) 1.6 (0.6-4.2) | 0.8 (0.5-1.3) 0.7 (0.4-1.0) |
| Samuelsson et al. 1991 | 167 | A | 1.1 (0.6-2.3) | 0.5 (0.3-0.9) |
| Epidemiology Group of the Research Committee of Inflammatory Bowel Disease in Japan 1994 | 76 | D | 2.4 (1.0-6.0) | 0.7 (0.2-2.0) **** |
| Case-control(continued) | ||||
|
Nakamura and Labarthe
1994; Nakamura et al. 1994 | 384¶
199 | D | 1.7 (1.0-2.9) 2.3 (0.9-5.7) | 0.3 (0.2-0.5) 0.4 (0.2-1.0) |
| Rutgeerts et al. 1994 | 174 | A | NR | Decreased risk¶¶¶ |
| Silverstein et al. 1994 | 100 | D | 1.2 (0.5-3.0) | 0.1 (0.1-0.4) |
| Reif et al. 1995 | 54 | A | No difference | No difference |
| Corrao et al. 1998 | 594 | D | 3.0 (2.1-4.3) | 0.9 (0.7-1.2) |
| Cohort | ||||
| Vessey et al. 1986 | 24¶ | D | Increased risk | Decreased risk¶¶¶ |
| Logan and Kay 1989 | 78 | D | NR | Decreased risk¶¶¶ |
Compared with those who never smoked, unless otherwise indicated.
A = Smoking status ascertained after diagnosis.
Statistically significant differences in relative risk by smoking status, p < 0.05.
Percentage of smokers differed significantly between cases and controls; p < 0.05.
Number of women.
Population-based study.
D = Smoking status ascertained before or soon after diagnosis.
NR = Not reported.
Compared with former smokers and those who never smoked.
>20 cigarettes/day.
From: Chapter 3. Health Consequences of Tobacco Use Among Women
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