Table 2.

Associations between regular use of aspirin and risk of pancreatic cancera

Aspirin useNo. of case patientsbNo. of control subjectsbOR (95% CI)P
n = 761n = 794
Ever use
 Yes871430.54 (0.40–0.73)10−4.2
Duration of use, y3.594.060.92 (0.87–0.97)0.0034
Categories of use duration, y
 Never use674651Ref.
 >0, <234470.69 (0.43–1.10)0.12
 ≥2, <423450.41 (0.24–0.69)10−3.0
 ≥430510.53 (0.33–0.86)0.0099
Time in past since starting use, y5.414.960.96 (0.92–1.00)0.034
Categories of starting time in past, y
 Never use674651Ref.
 >0, <223370.58 (0.34–1.00)0.051
 ≥2, <422430.44 (0.26–0.75)0.0027
 ≥442630.59 (0.39–0.90)0.014
Categories of ending time in past, y
 Never used6746512.30 (1.62–3.26)10−5.5
 Continuing current use57113Ref.
 >0, <215152.36 (1.06–5.25)0.035
 ≥215152.06 (0.92–4.60)0.077
Age at start of use, y62.764.40.90 (0.86–0.95)c10−4.5
Categories of age at start of use, y
 Never used674651Ref.
 >0, <6033430.68 (0.42–1.09)0.11
 ≥60, <7032520.55 (0.34–0.88)0.012
 ≥7022480.39 (0.23–0.68)10−3.1
Age at end of use, y66.368.40.91 (0.87–0.95)c10−4.6
Categories of age at end of use, y
 Never used674651Ref.
 >0, <6019310.53 (0.29–0.97)0.039
 ≥60, <7033420.69 (0.42–1.11)0.13
 ≥7035700.45 (0.29–0.70)10−3.3
  • aUnconditional logistic regression models were used to obtain the ORs and 95% CIs. All models were adjusted for age at interview (continuous), sex, education category (continuous), BMI at age 21 (continuous), years of cigarette smoking (continuous), number of cigarettes per day (continuous), H. pylori CagA seropositivity, ABO blood group A vs. non-A, and history of diabetes mellitus more than 3 years in the past. Each row in the table is a separate adjusted model.

  • bNumbers of subjects for the category variables. For the duration variables, these columns give the mean durations among aspirin ever users; the ORs are per one year of duration, and the P values represent trend associations.

  • cOR and confidence limits per a 10-year difference in age among aspirin ever users.