Background: Pancreatic cancer is a devastating disease for which the role of dietary factors remains inconclusive. The study objective was to evaluate risk of pancreatic cancer associated with meat preparation methods and meat-related mutagen consumption using a clinic-based case–control design.

Methods: There were 384 cases and 983 controls; subjects provided demographic information and completed a 144-item food frequency questionnaire, which was used to estimate meat mutagen intake using the National Cancer Institute's CHARRED database (Bethesda, MD). Logistic regression was used to calculate ORs and 95% confidence intervals (CI), adjusted for factors including age, sex, cigarette smoking, body mass index, and diabetes mellitus.

Results: Overall, the findings were null with respect to meat mutagen intake and pancreatic cancer.

Conclusions: The results do not support an association between well-done meat or meat-related mutagen intake and pancreatic cancer and contrast with generally increased risks reported in previous studies.

Impact: These data contribute to evidence about pancreatic cancer and potentially carcinogenic compounds in meat. Cancer Epidemiol Biomarkers Prev; 22(7); 1336–9. ©2013 AACR.

Authors of The World Cancer Research Fund Second Expert Report (1) evaluated literature on pancreatic cancer risk factors and concluded that current evidence suggests that red meat increases the risk. For meat mutagens and meat preparation/doneness preference, the evidence from 2 cohort and two case–control (2–6) studies has generally shown positive associations between pancreatic cancer and increasing intake of well-done grilled/barbecued meat, heterocyclic amines (HCA), and a mutagenicity activity index (MAI; revertants/grams of daily meat intake) based on mutagenicity in the Salmonella-based Ames Assay (7).

Our objective was to evaluate meat-related mutagen consumption for association with pancreatic cancer using a clinic-based case–control design. This study used a protocol to rapidly identify and enroll cases that were seen at the Mayo Clinic (Rochester, MN).

Study population description

This study was approved by the Mayo Clinic Institutional Review Board. The study population has been described in detail elsewhere (8).

Dietary data from FFQ

Participants were asked to complete a 144-item food frequency questionnaire (FFQ). Details are given in our previous report (8).

Meat mutagens

Meat-related responses from the FFQ and a meat-cooking module were used with a database, CHARRED (9), developed at the National Cancer Institute (Bethesda, MD) to estimate average intake of meat-related mutagens and the MAI. The database reports on the 3 most mass abundant of 15-plus identified HCAs known to accumulate in cooked meat, whereas the MAI is a more general measure of DNA-damaging potential.

Statistical analysis

Reported intake of grilled/barbecued and broiled red meat was analyzed by categories of doneness preferences. Intake in controls was split into quartiles with the reference group consisting of those who reported no intake. For meat-related mutagens and associations with pancreatic cancer, a logistic regression model was used to calculate ORs and 95% confidence intervals (CI) of pancreatic cancer adjusting for age, sex, usual adult body mass index (BMI; kg/m2), diabetes mellitus (none and those with diabetes diagnosis <3 years before cancer; diagnosis ≥3 years before cancer), energy intake (per 1,000 kcal), number of drinks of alcohol per week, education (<high school, high school, post-high school <4 years, post-high school 4+ years), race (non-Hispanic White, non-Hispanic Black, other), cigarette smoking status (never, quit 15+ years, quit < 15 years, current), pack-years (continuous), and pack-years squared (continuous). All statistical significance tests were 2-sided; P values < 0.05 were considered significant. All analyses were generated using SAS software [Version (9.2); ref. 10].

Compared with controls, cases were more likely to have a personal history of diabetes, be slightly older, be male, and have ever smoked cigarettes. Usual adult BMI was similar in the 2 groups. Using the same group of cases and controls, we previously conducted a sensitivity analysis for demographic characteristics comparing cases that did and did not complete the questionnaire and determined the 2 groups were similar (8).

Controls had significantly higher reported consumption of both grilled/barbecued and broiled meat than cases (Table 1) with OR (95% CI) for the highest versus lowest intake categories of 0.53 (0.34–0.84) and 0.67 (0.42–1.06), respectively.

Table 1.

Selected meat doneness preference categories associated with pancreatic adenocarcinoma

Quartile
1234Ptrend
Total red meat – grilled/barbecued, g/dayc,a     0.003 
Cases 51 156 107 70  
Median (range) 0 2.13 (0.11–2.72) 3.74 (2.75–8.02) 11.4 (8.08–80.51)  
OR (95% CI) 1.00 (ref) 0.98 (0.64–1.48) 0.76 (0.49–1.17) 0.53 (0.34–0.84)  
Total red meat – broiled, g/dayc,b     0.03 
Cases 272 52 31 29  
Median (range) 0 0.79 (0.11–1.02) 1.87 (1.08–3.4) 5.44 (3.57–32.77)  
OR (95% CI) 1.00 (ref) 0.86 (0.59–1.26) 0.58 (0.37–0.90) 0.67 (0.42–1.06)  
Quartile
1234Ptrend
Total red meat – grilled/barbecued, g/dayc,a     0.003 
Cases 51 156 107 70  
Median (range) 0 2.13 (0.11–2.72) 3.74 (2.75–8.02) 11.4 (8.08–80.51)  
OR (95% CI) 1.00 (ref) 0.98 (0.64–1.48) 0.76 (0.49–1.17) 0.53 (0.34–0.84)  
Total red meat – broiled, g/dayc,b     0.03 
Cases 272 52 31 29  
Median (range) 0 0.79 (0.11–1.02) 1.87 (1.08–3.4) 5.44 (3.57–32.77)  
OR (95% CI) 1.00 (ref) 0.86 (0.59–1.26) 0.58 (0.37–0.90) 0.67 (0.42–1.06)  

aTotal red meat not grilled/barbecued (continuous).

bTotal red meat not broiled (continuous).

cAdjusted for age, sex, usual adult BMI (continuous), smoking (never, quit 15+ years, quit < 15 years, current), pack-years (continuous), diabetes mellitus (no diabetes mellitus, diabetes mellitus 3+ years), education (less than high school, high school, post-high school <4 years, post-high school 4+ years), race (White non-Hispanic, Black non-Hispanic, other), total white meat (continuous).

View Large

Median carcinogen intake ranges OR, 95% CI, and trend test of OR across quintiles were calculated (Table 2). Overall, these findings were null. The observed difference in intake and corresponding ORs for white meat [0.71 (0.51, 0.98)] and for nitrates derived from processed meat [0.26 (0.17, 0.40)] indicates that controls had a significantly higher reported intake of each.

Table 2.

Total meat and meat-related mutagens associated with pancreatic adenocarcinoma

Quintiles
12345Ptrend
Total meata 
Total red meat 
Cases 153 144 125 190 172 0.62 
Median (range) 1.00 (ref) 0.85 (0.63–1.15) 0.72 (0.53–0.98) 1.00 (0.74–1.34) 0.85 (0.62–1.15)  
OR (95% CI) 13.59 (0.8–19.26) 24.06 (19.28–28.49) 32.48 (28.5–37.13) 42.61 (37.16–51) 62.69 (51.02–158.47)  
Total white meat 
Cases 167 194 155 167 101 0.02 
Median (range) 6.42 (0–9.18) 11.4 (9.19–13.71) 16.46 (13.72–20.17) 24.73 (20.19–31.79) 40.87 (31.8–171.77)  
OR (95% CI) 1.00 (ref) 1.36 (1.02–1.81) 0.98 (0.73–1.33) 1.16 (0.86–1.55) 0.71 (0.51–0.98)  
Meat-related mutagensb 
MeIQx, ng/day 
Cases 81 74 71 86 68 0.84 
Median (range) 4.82 (0–8.61) 12.6 (8.62–16.38) 21.61 (16.39–27.5) 36.37 (27.53–47.76) 68.38 (47.78–541.55)  
OR (95% CI) 1.00 (ref) 0.92 (0.62, 1.36) 0.92 (0.63, 1.36) 1.01 (0.69, 1.47) 0.91 (0.62, 1.35)  
PhIP, ng/day 
Cases 67 84 69 81 79 0.60 
Median (range) 7.72 (0–14.89) 24.4 (14.9–34.17) 45.31 (34.26–58.3) 77.04 (58.37–102.11) 162.2 (102.4–883.92)  
OR (95% CI) 1.00 (ref) 1.29 (0.87, 1.91) 1.01 (0.68, 1.51) 1.23 (0.83, 1.82) 1.15 (0.78, 1.71)  
diMeIQx, ng/day 
Cases 82 69 68 77 84 0.81 
Median (range) 0.18 (0–0.43) 0.69 (0.43–0.98) 1.33 (0.98–1.72) 2.35 (1.73–3.1) 4.41 (3.11–33.4)  
OR (95% CI) 1.00 (ref) 0.83 (0.56–1.23) 0.82 (0.55–1.21) 0.89 (0.61–1.31) 1.02 (0.70–1.49)  
Mutagenic activity, revertant colonies/day 
Cases 80 80 55 70 95 0.66 
Median (range) 803.93 (0–1386.84) 2004.63 (1386.91–2573.39) 3303.56 (2586.32–4195.92) 5089.08 (4199.96–6340.38) 9129.41 (6362.03–92590.62)  
OR (95% CI) 1.00 (ref) 1.05 (0.72–1.53) 0.67 (0.44–1.01) 0.87 (0.58–1.28) 1.21 (0.83–1.75)  
Benzo(α)pyrene, ng/day 
Cases 77 76 81 77 69 0.67 
Median (range) 1.33 (0–3.82) 6.68 (3.84–10.13) 14.35 (10.16–20.94) 26.91 (21.03–39.79) 57.73 (39.81–293.26)  
OR (95% CI) 1.00 (ref) 0.96 (0.65–1.41) 0.98 (0.67–1.44) 0.97 (0.66–1.44) 0.90 (0.61–1.33)  
Nitrate from processed meat – measured, mg/day 
Cases 125 79 72 60 48 <.0001 
Median (range) 0.01 (0–0.02) 0.03 (0.02–0.05) 0.06 (0.05–0.08) 0.1 (0.08–0.14) 0.26 (0.14–1.1)  
OR (95% CI) 1.00 (ref) 0.57 (0.40–0.83) 0.48 (0.33–0.70) 0.38 (0.26–0.57) 0.26 (0.17–0.40)  
Quintiles
12345Ptrend
Total meata 
Total red meat 
Cases 153 144 125 190 172 0.62 
Median (range) 1.00 (ref) 0.85 (0.63–1.15) 0.72 (0.53–0.98) 1.00 (0.74–1.34) 0.85 (0.62–1.15)  
OR (95% CI) 13.59 (0.8–19.26) 24.06 (19.28–28.49) 32.48 (28.5–37.13) 42.61 (37.16–51) 62.69 (51.02–158.47)  
Total white meat 
Cases 167 194 155 167 101 0.02 
Median (range) 6.42 (0–9.18) 11.4 (9.19–13.71) 16.46 (13.72–20.17) 24.73 (20.19–31.79) 40.87 (31.8–171.77)  
OR (95% CI) 1.00 (ref) 1.36 (1.02–1.81) 0.98 (0.73–1.33) 1.16 (0.86–1.55) 0.71 (0.51–0.98)  
Meat-related mutagensb 
MeIQx, ng/day 
Cases 81 74 71 86 68 0.84 
Median (range) 4.82 (0–8.61) 12.6 (8.62–16.38) 21.61 (16.39–27.5) 36.37 (27.53–47.76) 68.38 (47.78–541.55)  
OR (95% CI) 1.00 (ref) 0.92 (0.62, 1.36) 0.92 (0.63, 1.36) 1.01 (0.69, 1.47) 0.91 (0.62, 1.35)  
PhIP, ng/day 
Cases 67 84 69 81 79 0.60 
Median (range) 7.72 (0–14.89) 24.4 (14.9–34.17) 45.31 (34.26–58.3) 77.04 (58.37–102.11) 162.2 (102.4–883.92)  
OR (95% CI) 1.00 (ref) 1.29 (0.87, 1.91) 1.01 (0.68, 1.51) 1.23 (0.83, 1.82) 1.15 (0.78, 1.71)  
diMeIQx, ng/day 
Cases 82 69 68 77 84 0.81 
Median (range) 0.18 (0–0.43) 0.69 (0.43–0.98) 1.33 (0.98–1.72) 2.35 (1.73–3.1) 4.41 (3.11–33.4)  
OR (95% CI) 1.00 (ref) 0.83 (0.56–1.23) 0.82 (0.55–1.21) 0.89 (0.61–1.31) 1.02 (0.70–1.49)  
Mutagenic activity, revertant colonies/day 
Cases 80 80 55 70 95 0.66 
Median (range) 803.93 (0–1386.84) 2004.63 (1386.91–2573.39) 3303.56 (2586.32–4195.92) 5089.08 (4199.96–6340.38) 9129.41 (6362.03–92590.62)  
OR (95% CI) 1.00 (ref) 1.05 (0.72–1.53) 0.67 (0.44–1.01) 0.87 (0.58–1.28) 1.21 (0.83–1.75)  
Benzo(α)pyrene, ng/day 
Cases 77 76 81 77 69 0.67 
Median (range) 1.33 (0–3.82) 6.68 (3.84–10.13) 14.35 (10.16–20.94) 26.91 (21.03–39.79) 57.73 (39.81–293.26)  
OR (95% CI) 1.00 (ref) 0.96 (0.65–1.41) 0.98 (0.67–1.44) 0.97 (0.66–1.44) 0.90 (0.61–1.33)  
Nitrate from processed meat – measured, mg/day 
Cases 125 79 72 60 48 <.0001 
Median (range) 0.01 (0–0.02) 0.03 (0.02–0.05) 0.06 (0.05–0.08) 0.1 (0.08–0.14) 0.26 (0.14–1.1)  
OR (95% CI) 1.00 (ref) 0.57 (0.40–0.83) 0.48 (0.33–0.70) 0.38 (0.26–0.57) 0.26 (0.17–0.40)  

*aAdjusted for age, sex, usual adult BMI (continuous), cigarette smoking (ever, former, never), diabetes mellitus (no diabetes mellitus, diabetes mellitus 3+ years), education (less than high school, high school, post-high school <4 years, post-high school 4+ years), race (non-Hispanic White, non-Hispanic Black, other).

bChanged the adjustment fro cigarette smoking (never, quit 15+ years, quit < 15 years, current), and additionally adjusted for pack-years (continuous), pack-years squared (continuous).

View Large

Given the previous literature, we hypothesized that there would be positive associations between pancreatic cancer and estimated intake of well-done grilled/barbecued meat, heterocyclic amines, benzo(a)pyrene, and the MAI. However, in general, our results were null with inverse associations between pancreatic cancer and intake of grilled/barbecued and broiled red meat, and nitrate derived from processed meat. Because more than 90% of dietary nitrate intake is from vegetables (11) and because the CHARRED database only assesses mutagen-related intake from meat, we cannot assess overall nitrate intake with pancreatic cancer.

Because meat mutagens (e.g., PhIP, MeQIx, and DiMeIQx) need to be metabolically activated before they form DNA adducts and initiate potential carcinogenic changes (12), there may be positive associations between pancreatic cancer and the HCA meat mutagens among subgroups of individuals in our study with particular polymorphisms in metabolism/antioxidant genes. We will be examining this possibility in future research.

Each of the numerous steps involved in estimating meat-borne carcinogen intake for individuals is prone to measurement error and exposure misclassification including reported intake from a FFQ and laboratory-based carcinogen measurements in specific food samples. We sought to avoid potential biases from assessing diet in individuals with pancreatic cancer (or other conditions) who may have recently changed their intake of meat, by removing participants who reported changing their diet within the last 5 years. However, this also reduced the sample size and our power to detect potential effects.

No potential conflicts of interest were disclosed.

Conception and design: W.R. Bamlet, J.E. Olson, G.M. Petersen, R. Sinha, K.E. Anderson

Development of methodology: R.Z. Stolzenberg-Solomon, J.E. Olson, R. Sinha

Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): W.R. Bamlet, G.M. Petersen, R. Sinha

Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis): R.J. Jansen, D.P. Robinson, R.D. Frank, R.Z. Stolzenberg-Solomon, W.R. Bamlet, A.L. Oberg, K.G. Rabe, G.M. Petersen, R. Sinha, K.E. Anderson

Writing, review, and/or revision of the manuscript: R.J. Jansen, R.Z. Stolzenberg-Solomon, W.R. Bamlet, A.L. Oberg, K.G. Rabe, G.M. Petersen, K.E. Anderson

Administrative, technical, or material support (i.e., reporting or organizing data, constructing databases): R.J. Jansen, W.R. Bamlet

Study supervision: G.M. Petersen

The authors thank the study participants, their clinical colleagues, study coordinators, and other research personnel for their contributions to this study.

This work was supported by partial funding by R25TCA92049 and Mayo Clinic SPORE in Pancreatic Cancer (P50 CA102701).

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2013