Introduction: Identifying modifiable risk factors for pancreatic cancer is important because of its poor prognosis. Previous findings on diet are inconsistent.

Methods: Associations between intake of nutrients, food groups, dietary patterns, and pancreatic cancer risk were examined among 34,642 postmenopausal women in the Iowa Women's Health Study (IWHS).

Results: No significant associations were observed between intake of nutrients and food groups or dietary patterns and pancreatic cancer.

Conclusion: Our findings do not support the hypothesis that fruits, vegetables, and red meat are associated with risk of pancreatic cancer.

Impact: Dietary intake, assessed in multiple aspects in a large prospective cohort study, was not associated with pancreatic cancer. Cancer Epidemiol Biomarkers Prev; 20(4); 711–4. ©2011 AACR.

Pancreatic cancer has an extremely poor diagnosis with a 5-year survival rate of 6%, thus identifying modifiable pancreatic cancer risk factors is important (1). A number of studies have examined the link between diet and pancreatic cancer, but the findings have been inconclusive. Reduced pancreatic cancer risk has been associated with high fruit and vegetable intake and low red meat intake mostly in case–control studies, which are subject to biases (2, 3). We examined associations between dietary intake of nutrients, food groups, and dietary patterns with pancreatic cancer using data from a large prospective cohort study of postmenopausal women to test our hypothesis that high fruit and vegetable intake and low red meat intake are associated with reduced pancreatic cancer risk.

The Iowa Women's Health Study (IWHS) is a prospective cohort study of cancer among women in Iowa. In 1986, 41,836 women (42%) of the 99,826 randomly selected women aged 55 to 69 years in Iowa completed a self-administered questionnaire including the Harvard food frequency questionnaire (FFQ). We excluded 3,896 women with a history of cancer at baseline (except nonmelanoma skin cancer), 2,781 women with greater than 30 items blank on FFQ or implausible energy intake (<600 or >5,000 kcal/d), 513 premenopausal women, and 4 atypical pancreatic tumors (ICD-O-3 codes 81503, 82463, and 88903). Incident pancreatic cancers diagnosed in Iowa through the end of 2007 were ascertained by the Iowa Department of Health Registry. A total of 256 incident pancreatic cancers among 34,642 cohort members during the 16.3 mean person-years were included in the analysis. This study was approved by the University of Minnesota Institutional Review Board.

Dietary intake of 19 nutrients and 23 food groups and dietary pattern scores were adjusted for total energy intake using residual and density methods, respectively. Dietary patterns were derived by principal component analysis using an orthogonal rotation procedure. Factor scores for 6 dietary patterns were computed for each study subject. Logarithmically transformed values were used for dietary exposures because of skewed distributions.

We estimated HRs and 95% CIs for pancreatic cancer in upper quintiles of dietary exposures with the lowest quintile as a reference group using Cox proportional hazard regression models. In multivariate models, age, race, education, alcohol intake, smoking status, and physical activity were included as covariates. Body mass index (BMI) and diabetes might be on the causal pathway between diet and pancreatic cancer and thus were added separately from other covariates. This study had 80% power to detect an HR in the range of 1.42 to 1.59 for total vegetables, total fruits, red meat, total energy, and carbohydrate and 1.63 for dietary patterns.

Table 1 shows baseline characteristics and pancreatic cancer risk. The mean age of the participants was 61.5 years and the participants were primarily white (92.8%). Older age, current cigarette smoking, and history of diabetes were significantly associated with pancreatic cancer; women with BMI of 30 or greater had a 10% increased risk of borderline significance. There were no associations between dietary intake of any nutrients or food groups and pancreatic cancer (Table 2). Adjusting for BMI or diabetes history did not change the results (data not shown). Similarly, no associations were observed between dietary patterns and pancreatic cancer.

Table 1.

Baseline characteristics and risk of pancreatic cancer

Cases (n = 256)Person-yearsIncidence rateaHRb (95% CI)Pc
Age (mean ± SD), y 
 <60 74 (28.9%) 215,407 34.4 1.0 <0.0001 
 60 to <65 91 (35.6%) 199,979 45.5 1.4 (1.0–1.8)  
 ≥65 91 (35.6%) 147,910 61.5 1.9 (1.4–2.6)  
BMI (mean ± SD) 
 <25 123 (48.0%) 271,774 45.3 1.0 0.35 
 25 to <30 78 (30.5%) 191,675 40.7 0.9 (0.7–1.2)  
 ≥30 55 (21.5%) 99,847 55.1 1.1 (1.0–1.2)  
Race 
 White 250 (99.6%) 552,869 45.2 1.0 0.52 
 Others 1 (0.4%) 4,457 22.4 0.5 (0.1–3.7)  
Education 
 Less than High school 47 (18.4%) 101,635 46.2 1.0 0.81 
 High school 106 (41.4%) 239,376 44.3 1.0 (0.7–1.4)  
 Greater than High school 103 (40.2%) 222,285 46.3 1.0 (0.7–1.5)  
Cigarette smoking 
 Never smoker 161 (63.9%) 377,586 42.6 1.0 0.001 
 Former smoker 40 (15.9%) 103,947 38.5 1.0 (0.7–1.4)  
 Current smoker 51 (20.2%) 74,271 68.7 1.9 (1.4–2.5)  
Alcohol intake 
 No 136 (53.1%) 309,944 43.9 1.0 0.36 
 Yes 120 (48.9%) 253,352 47.4 (0.9–1.4)  
Physical activity 
 Low 130 (51.0%) 259,284 50.1 1.0 0.17 
 Moderate 64 (25.1%) 154,389 41.5 0.8 (0.6–1.1)  
 High 61 (23.4%) 141,059 43.2 0.9 (0.6–1.2)  
History of diabetes 
 No 232 (91.3%) 531,889 43.6 1.0 0.007 
 Yes 22 (8.7%) 27,667 79.5 1.9 (1.2–3.0)  
Cases (n = 256)Person-yearsIncidence rateaHRb (95% CI)Pc
Age (mean ± SD), y 
 <60 74 (28.9%) 215,407 34.4 1.0 <0.0001 
 60 to <65 91 (35.6%) 199,979 45.5 1.4 (1.0–1.8)  
 ≥65 91 (35.6%) 147,910 61.5 1.9 (1.4–2.6)  
BMI (mean ± SD) 
 <25 123 (48.0%) 271,774 45.3 1.0 0.35 
 25 to <30 78 (30.5%) 191,675 40.7 0.9 (0.7–1.2)  
 ≥30 55 (21.5%) 99,847 55.1 1.1 (1.0–1.2)  
Race 
 White 250 (99.6%) 552,869 45.2 1.0 0.52 
 Others 1 (0.4%) 4,457 22.4 0.5 (0.1–3.7)  
Education 
 Less than High school 47 (18.4%) 101,635 46.2 1.0 0.81 
 High school 106 (41.4%) 239,376 44.3 1.0 (0.7–1.4)  
 Greater than High school 103 (40.2%) 222,285 46.3 1.0 (0.7–1.5)  
Cigarette smoking 
 Never smoker 161 (63.9%) 377,586 42.6 1.0 0.001 
 Former smoker 40 (15.9%) 103,947 38.5 1.0 (0.7–1.4)  
 Current smoker 51 (20.2%) 74,271 68.7 1.9 (1.4–2.5)  
Alcohol intake 
 No 136 (53.1%) 309,944 43.9 1.0 0.36 
 Yes 120 (48.9%) 253,352 47.4 (0.9–1.4)  
Physical activity 
 Low 130 (51.0%) 259,284 50.1 1.0 0.17 
 Moderate 64 (25.1%) 154,389 41.5 0.8 (0.6–1.1)  
 High 61 (23.4%) 141,059 43.2 0.9 (0.6–1.2)  
History of diabetes 
 No 232 (91.3%) 531,889 43.6 1.0 0.007 
 Yes 22 (8.7%) 27,667 79.5 1.9 (1.2–3.0)  

aPer 100,000 person-years.

bAge-adjusted HR and 95% CI.

cWald χ2 test.

Table 2.

Dietary intake of nutrients, food groups and dietary patterns and risk of pancreatic cancer

Quintiles of dietary intake or dietary pattern scoresPtrend
1 (lowest)2345 (highest)
Nutrient intake       
Total calorie       
 Median, kcal/d 1,107 1,449 1,718 2,027 2,567  
 Cases 56 50 51 44 55  
 Age-adjusted HR 1.0 0.88 (0.60–1.28) 0.89 (0.61–1.30) 0.77 (0.52–1.15) 0.96 (0.66–1.39) 0.77 
 Multivariate HRa 1.0 0.90 (0.61–1.32) 0.86 (0.58–1.27) 0.81 (0.54–1.21) 0.97 (0.66–1.42) 0.81 
Carbohydrate       
 Median, g/d 141.0 182.0 203.3 222.0 252.7  
 Cases 53 74 43 44 42  
 Age-adjusted HR 1.0 1.32 (0.93–1.88) 0.75 (0.50–1.12) 0.75 (0.50–1.12) 0.71 (0.47–1.07) 0.008 
 Multivariate HRa 1.0 1.38 (0.96–1.99) 0.83 (0.55–1.25) 0.84 (0.56–1.27) 0.81 (0.53–1.23) 0.06 
Vitamin C       
 Median, mg/d 82.40 137.50 184.25 271.80 678.55  
 Cases 53 55 47 54 47  
 Age-adjusted HR 1.0 0.99 (0.68–1.45) 0.84 (0.57–1.25) 0.98 (0.67–1.44) 0.87 (0.59–1.29) 0.53 
 Multivariate HRa 1.0 1.09 (0.73–1.62) 0.97 (0.65–1.46) 1.16 (0.78–1.72) 0.99 (0.66–1.49) 0.84 
Vitamin E       
 Median, mg/d 5.2 6.9 8.7 22.1 241.0  
 Cases 56 51 59 51 39  
 Age-adjusted HR 1.0 0.88 (0.60–1.29) 1.03 (0.71–1.48) 0.89 (0.61–1.30) 0.68 (0.45–1.02) 0.05 
 Multivariate HRa 1.0 0.93 (0.63–1.38) 1.07 (0.73–1.57) 0.95 (0.65–1.41) 0.76 (0.50–1.16) 0.13 
Food group intake       
Total vegetables       
 Median (servings/wk) 11.5 17.5 22.0 28.0 40.0  
 Cases 48 43 53 56 56  
 Age-adjusted HR 1.0 0.89 (0.59–1.35) 1.09 (0.74–1.61) 1.14 (0.78–1.68) 1.16 (0.79–1.70) 0.26 
 Multivariate HRa 1.0 0.82 (0.53–1.26) 1.13 (0.76–1.68) 1.15 (0.77–1.71) 1.21 (0.81–1.80) 0.14 
Total fruits       
 Median (servings/wk) 6.5 12.5 16.5 21.0 29.5  
 Cases 51 53 61 48 43  
 Age-adjusted HR 1.0 0.96 (0.65–1.41) 1.10 (0.75–1.59) 0.85 (0.57–1.27) 0.77 (0.51–1.15) 0.15 
 Multivariate HRa 1.0 1.12 (0.75–1.67) 1.27 (0.86–1.88) 1.02 (0.67–1.55) 0.98 (0.64–1.50) 0.71 
Total vegetables and fruits       
 Median, servings/wk 22.0 32.0 4.0 48.0 64.5  
 Cases 51 46 58 47 54  
 Age-adjusted HR 1.0 0.85 (0.57–1.27) 1.07 (0.73–1.55) 0.85 (0.57–1.27) 1.00 (0.68–1.46) 0.97 
 Multivariate HRa 1.0 0.95 (0.63–1.43) 1.15 (0.77–1.71) 1.00 (0.66–1.51) 1.18 (0.79–1.77) 0.38 
Red meat       
 Median, servings/wk 2.0 3.5 5.0 7.0 9.0  
 Cases 54 43 52 55 52  
 Age-adjusted HR 1.0 0.79 (0.53–1.18) 0.95 (0.65–1.39) 1.00 (0.69–1.46) 0.96 (0.65–1.40) 0.78 
 Multivariate HRa 1.0 0.85 (0.57–1.28) 0.99 (0.67–1.47) 1.06 (0.72–1.55) 0.97 (0.65–1.44) 0.79 
Dietary pattern scores       
High vegetable       
 Cases 49 43 58 50 56  
 Age-adjusted HR 1.0 0.89 (0.59–1.34) 1.20 (0.82–1.76) 1.05 (0.71–1.56) 1.23 (0.84–1.81) 0.06 
 Multivariate HRa 1.0 0.83 (0.54–1.26) 1.19 (0.81–1.75) 1.04 (0.69–1.56) 1.25 (0.84–1.87) 0.03 
Low fat       
 Cases 56 50 48 52 50  
 Age-adjusted HR 1.050 0.82 (0.56–1.20) 0.76 (0.52–1.12) 0.80 (0.54–1.17) 0.76 (0.52–1.12) 0.23 
 Multivariate HR* 1.0 0.93 (0.62–1.38) 0.90 (0.60–1.36) 0.95 (0.63–1.42) 0.97 (0.64–1.47) 0.99 
Mediterranean       
 Cases 54 50 39 53 60  
 Age-adjusted HR 1.0 0.96 (0.65–1.41) 0.77 (0.51–1.16) 1.09 (0.75–1.59) 1.32 (0.91–1.92) 0.07 
 Multivariate HRa 1.0 0.92 (0.62–1.36) 0.69 (0.44–1.06) 1.00 (0.67–1.49) 1.27 (0.84–1.90) 0.14 
High fiber       
 Cases 54 56 44 56 46  
 Age-adjusted HR 1.0 0.97 (0.66–1.41) 0.73 (0.49–1.09) 0.92 (0.63–1.34) 0.73 (0.49–1.09) 0.20 
 Multivariate HRa 1.0 1.04 (0.71–1.53) 0.79 (0.52–1.19) 1.08 (0.73–1.60) 0.85 (0.56–1.29) 0.74 
High sweet       
 Cases 50 48 59 59 40  
 Age-adjusted HR 1.0 0.89 (0.60–1.32) 1.08 (0.74–1.58) 1.08 (0.74–1.57) 0.74 (0.49–1.12) 0.11 
 Multivariate HRa 1.0 0.93 (0.63–1.39) 1.05 (0.71–1.55) 1.09 (0.74–1.60) 0.74 (0.48–1.13) 0.10 
High fruit       
 Cases 52 52 55 49 48  
 Age-adjusted HR 1.0 0.97 (0.66–1.42) 1.03 (0.70–1.50) 0.91 (0.61–1.34) 0.91 (0.62–1.35) 0.28 
 Multivariate HRa 1.0 0.96 (0.65–1.42) 1.05 (0.72–1.55) 0.94 (0.63–1.40) 0.96 (0.64–1.43) 0.41 
Quintiles of dietary intake or dietary pattern scoresPtrend
1 (lowest)2345 (highest)
Nutrient intake       
Total calorie       
 Median, kcal/d 1,107 1,449 1,718 2,027 2,567  
 Cases 56 50 51 44 55  
 Age-adjusted HR 1.0 0.88 (0.60–1.28) 0.89 (0.61–1.30) 0.77 (0.52–1.15) 0.96 (0.66–1.39) 0.77 
 Multivariate HRa 1.0 0.90 (0.61–1.32) 0.86 (0.58–1.27) 0.81 (0.54–1.21) 0.97 (0.66–1.42) 0.81 
Carbohydrate       
 Median, g/d 141.0 182.0 203.3 222.0 252.7  
 Cases 53 74 43 44 42  
 Age-adjusted HR 1.0 1.32 (0.93–1.88) 0.75 (0.50–1.12) 0.75 (0.50–1.12) 0.71 (0.47–1.07) 0.008 
 Multivariate HRa 1.0 1.38 (0.96–1.99) 0.83 (0.55–1.25) 0.84 (0.56–1.27) 0.81 (0.53–1.23) 0.06 
Vitamin C       
 Median, mg/d 82.40 137.50 184.25 271.80 678.55  
 Cases 53 55 47 54 47  
 Age-adjusted HR 1.0 0.99 (0.68–1.45) 0.84 (0.57–1.25) 0.98 (0.67–1.44) 0.87 (0.59–1.29) 0.53 
 Multivariate HRa 1.0 1.09 (0.73–1.62) 0.97 (0.65–1.46) 1.16 (0.78–1.72) 0.99 (0.66–1.49) 0.84 
Vitamin E       
 Median, mg/d 5.2 6.9 8.7 22.1 241.0  
 Cases 56 51 59 51 39  
 Age-adjusted HR 1.0 0.88 (0.60–1.29) 1.03 (0.71–1.48) 0.89 (0.61–1.30) 0.68 (0.45–1.02) 0.05 
 Multivariate HRa 1.0 0.93 (0.63–1.38) 1.07 (0.73–1.57) 0.95 (0.65–1.41) 0.76 (0.50–1.16) 0.13 
Food group intake       
Total vegetables       
 Median (servings/wk) 11.5 17.5 22.0 28.0 40.0  
 Cases 48 43 53 56 56  
 Age-adjusted HR 1.0 0.89 (0.59–1.35) 1.09 (0.74–1.61) 1.14 (0.78–1.68) 1.16 (0.79–1.70) 0.26 
 Multivariate HRa 1.0 0.82 (0.53–1.26) 1.13 (0.76–1.68) 1.15 (0.77–1.71) 1.21 (0.81–1.80) 0.14 
Total fruits       
 Median (servings/wk) 6.5 12.5 16.5 21.0 29.5  
 Cases 51 53 61 48 43  
 Age-adjusted HR 1.0 0.96 (0.65–1.41) 1.10 (0.75–1.59) 0.85 (0.57–1.27) 0.77 (0.51–1.15) 0.15 
 Multivariate HRa 1.0 1.12 (0.75–1.67) 1.27 (0.86–1.88) 1.02 (0.67–1.55) 0.98 (0.64–1.50) 0.71 
Total vegetables and fruits       
 Median, servings/wk 22.0 32.0 4.0 48.0 64.5  
 Cases 51 46 58 47 54  
 Age-adjusted HR 1.0 0.85 (0.57–1.27) 1.07 (0.73–1.55) 0.85 (0.57–1.27) 1.00 (0.68–1.46) 0.97 
 Multivariate HRa 1.0 0.95 (0.63–1.43) 1.15 (0.77–1.71) 1.00 (0.66–1.51) 1.18 (0.79–1.77) 0.38 
Red meat       
 Median, servings/wk 2.0 3.5 5.0 7.0 9.0  
 Cases 54 43 52 55 52  
 Age-adjusted HR 1.0 0.79 (0.53–1.18) 0.95 (0.65–1.39) 1.00 (0.69–1.46) 0.96 (0.65–1.40) 0.78 
 Multivariate HRa 1.0 0.85 (0.57–1.28) 0.99 (0.67–1.47) 1.06 (0.72–1.55) 0.97 (0.65–1.44) 0.79 
Dietary pattern scores       
High vegetable       
 Cases 49 43 58 50 56  
 Age-adjusted HR 1.0 0.89 (0.59–1.34) 1.20 (0.82–1.76) 1.05 (0.71–1.56) 1.23 (0.84–1.81) 0.06 
 Multivariate HRa 1.0 0.83 (0.54–1.26) 1.19 (0.81–1.75) 1.04 (0.69–1.56) 1.25 (0.84–1.87) 0.03 
Low fat       
 Cases 56 50 48 52 50  
 Age-adjusted HR 1.050 0.82 (0.56–1.20) 0.76 (0.52–1.12) 0.80 (0.54–1.17) 0.76 (0.52–1.12) 0.23 
 Multivariate HR* 1.0 0.93 (0.62–1.38) 0.90 (0.60–1.36) 0.95 (0.63–1.42) 0.97 (0.64–1.47) 0.99 
Mediterranean       
 Cases 54 50 39 53 60  
 Age-adjusted HR 1.0 0.96 (0.65–1.41) 0.77 (0.51–1.16) 1.09 (0.75–1.59) 1.32 (0.91–1.92) 0.07 
 Multivariate HRa 1.0 0.92 (0.62–1.36) 0.69 (0.44–1.06) 1.00 (0.67–1.49) 1.27 (0.84–1.90) 0.14 
High fiber       
 Cases 54 56 44 56 46  
 Age-adjusted HR 1.0 0.97 (0.66–1.41) 0.73 (0.49–1.09) 0.92 (0.63–1.34) 0.73 (0.49–1.09) 0.20 
 Multivariate HRa 1.0 1.04 (0.71–1.53) 0.79 (0.52–1.19) 1.08 (0.73–1.60) 0.85 (0.56–1.29) 0.74 
High sweet       
 Cases 50 48 59 59 40  
 Age-adjusted HR 1.0 0.89 (0.60–1.32) 1.08 (0.74–1.58) 1.08 (0.74–1.57) 0.74 (0.49–1.12) 0.11 
 Multivariate HRa 1.0 0.93 (0.63–1.39) 1.05 (0.71–1.55) 1.09 (0.74–1.60) 0.74 (0.48–1.13) 0.10 
High fruit       
 Cases 52 52 55 49 48  
 Age-adjusted HR 1.0 0.97 (0.66–1.42) 1.03 (0.70–1.50) 0.91 (0.61–1.34) 0.91 (0.62–1.35) 0.28 
 Multivariate HRa 1.0 0.96 (0.65–1.42) 1.05 (0.72–1.55) 0.94 (0.63–1.40) 0.96 (0.64–1.43) 0.41 

Note: HRs and 95% CIs in parentheses.

aAdjusted for age (continuous), race, education (less than high school, high school, greater than high school), alcohol intake (yes/no), smoking (current, past, never smoker), physical activity (low, moderate, high).

In the present study, dietary intake of nutrients, food groups, and dietary patterns were not associated with pancreatic cancer. Our results indicate that dietary factors, as assessed, are not risk factors for pancreatic cancer in this population. These results are consistent with results from other large cohort study results (4–7). Strengths of this study include a large sample size, a prospective study design, and a nearly complete follow-up.

Nonetheless, nondifferential misclassification of dietary intake is possible in most cohort studies assessing dietary intake using FFQs. Furthermore, FFQs may not capture the information that might be most relevant to pancreatic cancer risk such as food preparation methods, food additives, and contaminants. In the current study, we could not assess meat preparation such as cooking methods and doneness. These factors should be assessed in relation to pancreatic cancer in future prospective cohort studies.

In summary, our findings do not support the hypothesis that fruits, vegetables, and red meat are associated with pancreatic cancer.

No potential conflicts of interest were disclosed.

This study was funded by the National Cancer institute (RO1 CA39742).

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