Folate intake and pancreatic cancer incidence: a prospective study of Swedish women and men.
BACKGROUND
Epidemiologic evidence supports an association between high folate intake and reduced risk of some cancers, in particular colorectal cancer. However, epidemiologic data concerning the relationship between folate and pancreatic cancer risk are sparse. We examined the association between folate intake and risk of pancreatic cancer in a population-based prospective study of Swedish women and men.


METHODS
We prospectively followed 81,922 women and men in the Swedish Mammography Cohort and the Cohort of Swedish Men who were cancer-free and completed a 96-item food-frequency questionnaire in 1997. Cox proportional hazards models were used to estimate multivariable rate ratios (RRs) with 95% confidence intervals (CIs). All statistical tests were two-sided.


RESULTS
A total of 135 incident pancreatic cancer cases were diagnosed during a mean follow-up of 6.8 years. In multivariable analyses controlling for age, smoking, fruit and vegetable consumption, and other potential confounders, dietary and total folate intakes were statistically significantly inversely associated with risk of pancreatic cancer. The multivariable rate ratios of pancreatic cancer for those in the highest category of folate intake (> or = 350 microg/day) compared with the lowest category of intake (< 200 microg/day) were 0.25 (95% CI = 0.11 to 0.59; Ptrend = .002) for dietary folate and 0.33 (95% CI = 0.15 to 0.72; Ptrend = .01) for total folate (combining dietary and supplemental sources). Folic acid from supplements was not associated with pancreatic cancer (for > or = 300 microg/day compared with 0 microg/day of supplemental folic acid, multivariable RR = 1.02; 95% CI = 0.56 to 1.88). The sex- and age-standardized incidence rates of pancreatic cancer per 100,000 person-years were 41 for the lowest and 18 for the highest category of dietary folate intake.


CONCLUSIONS
Our results suggest that increased intake of folate from food sources, but not from supplements, may be associated with a reduced risk of pancreatic cancer.
Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. susanna.larsson@ki.se
Susanna C
SC
Larsson
Niclas
N
Håkansson
Edward
E
Giovannucci
Alicja
A
Wolk
D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D016588:Anticarcinogenic Agents / Q000008:administration & dosage* / Q000378:metabolism; D019587:Dietary Supplements; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000378:metabolism; D005638:Fruit; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010190:Pancreatic Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D016896:Treatment Outcome; D014675:Vegetables
D016588:Anticarcinogenic Agents; D005492:Folic Acid