and show the baseline characteristics of the cases and controls for the ATBC and PLCO cohorts, respectively. Cases and controls tended to have similar baseline characteristics (–). In ATBC, compared to controls, cases had a significantly lower CRP concentrations (P=0.03), and greater height (P=0.04), total fat (P=0.04) and red meat intake (P=0.01); and tended to be more educated (P=0.02). In PLCO, compared to controls, cases were more likely to be current smokers (P<0.0001) and had lower carbohydrate (P=0.02), energy (P=0.05), and protein intake (P=0.05).
shows the means or proportions of selected characteristics among control participants according to quintile of CRP concentration in the ATBC and PLCO studies, respectively. Higher CRP concentrations were directly associated with increasing BMI, obesity, and less vigorous (PLCO) or more sedentary (ATBC) leisure activity, and inversely associated with normal BMI and exercising to keep fit (ATBC) or more vigorous activity (PLCO). In the ATBC controls, higher CRP concentrations were positively associated with not working (P=0.04). In PLCO, higher CRP concentrations were associated with current smoking (P=0.01) and a medical history of diabetes (P=0.001).
shows the main effects for the association between CRP and pancreatic cancer in the ATBC, PLCO, and combined nested case-control set. In ATBC, higher concentrations of CRP tended to be inversely associated with pancreatic cancer (high compared to low quintile, OR, 0.71; 95% CI, 0.44–1.16, p-trend=0.03, continuous OR, 0.94; 95% CI, 0.89–0.99). The inverse association remained when we excluded cases that occurred earlier during follow-up (i.e., high compared to low quintile CRP, cases occurring ≥ 5 years OR, 0.71; 95% CI, 0.41–1.23; Ptrend= 0.05, continuous OR, 0.92; 95% CI, 0.86–0.99; and ≥ 10 years OR, 0.57; 95% CI, 0.26–1.22; Ptrend= 0.03, continuous OR, 0.93; 95% CI, 0.85–1.01). In PLCO, higher concentrations of CRP were not significantly associated with pancreatic cancer risk (high compared to low quintile, OR, 0.84; 95% CI, 0.41–1.74; Ptrend=0.79, continuous OR=0.99, 95% CI 0.95–1.04). There was no association when early cases were excluded (high compared to low quintile, ≥5 years smoking-adjusted OR, 0.97; 95% CI, 0.90–1.05; Ptrend=0.41). However, we observed a non-significant positive association for longer follow-up (high compared to low quintile, ≥8 years smoking-adjusted OR, 1.24; 95% CI, 0.92–1.66; Ptrend=0.33). There was no association between CRP concentrations and pancreatic cancer in the combined analyses based on overall pooled cut-points (high compared to low quintile, OR, 1.00; 95% CI, 0.69–1.46; Ptrend=0.12, continuous OR, 0.98; 95% CI, 0.95–1.01) and cohort-specific cut-points (OR, 1.01; 95% CI, 0.70–1.46; Ptrend=0.76). In the pooled analyses we observed suggestive inverse associations among cases with longer follow-up (≥5 years smoking-adjusted OR, 0.87; 95% CI, 0.55–1.37; Ptrend=0.48, continuous OR, 0.95; 95% CI, 0.86–1.05).
Table 4 Odds Ratios (OR) and 95% Confidence Intervals (CI) for Pancreatic Cancer by Quintile of Baseline Serum CRP Concentrations in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (more ...)
shows the association between CRP concentrations and pancreatic cancer stratified by age. Although no significant associations were observed in either the ATBC or PLCO datasets separately (p-interaction=0.91 and 0.05, respectively), in the combined analyses we observed a significant interaction by age (p-interaction=0.02) such that younger participants had a non-significant inverse association and trend (high compared to low quintile, OR=0.81, 95% CI 0.45–1.47, p-trend=0.17), while older participants tended to have a pattern of non-significant elevated risk with increasing CRP concentrations. We did not observe a significant interaction of the CRP and pancreatic cancer association by BMI or smoking status in either the ATBC or PLCO studies.
Table 5 Variable-Adjusted ORs and 95% Confidence Intervals of Baseline Serum CRP Concentrations and Pancreatic Cancer Stratified by Median Age in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening (more ...)