Table 3.

Pooled relative risks of pancreatic cancer for dietary folate intake among nonusers of supplements containing folic acid^*

	RR (95% CI)					Ptrend‡	Pbetween-studies heterogeneity§	Pbetween-studies heterogeneity due to sex║
	Quintile of dietary folate intake†
	1	2	3	4	5
No. of cancers	272	291	256	252	297
Age-adjusted	1.00 (referent)	1.06 (0.89 to 1.26)	0.94 (0.77 to 1.13)	0.93 (0.78 to 1.11)	1.12 (0.95 to 1.33)	.43	.73	.41
Multivariable¶	1.00 (referent)	1.12 (0.94 to 1.33)	1.01 (0.84 to 1.21)	1.01 (0.84 to 1.22)	1.20 (1.01 to 1.43)	.08	.42	.36

^*Folate intake was adjusted for energy intake. The Melbourne Collaborative Cohort Study and the Canadian National Breast Screening Study were not included because total folate data were not available in these two studies. CI = confidence interval; RR = relative risk.

^†The quintiles were defined within each individual study among nonusers of supplements containing folic acid.

^‡P values were calculated using two-sided Wald test.

^§P values were for the highest quintile and were calculated using the Q statistic.

^‖P values were for the highest quintile and were calculated using the two-sided Wald test.

^¶Adjusted for body mass index (kg/m², continuous), diabetes (yes, no), alcohol intake (g/d; 0, 0.1–14.9, 15.0–29.9, ≥30), energy intake (kcal/d, continuous), and cigarette smoking (never, former [<15, ≥15 pack-years], current [<40, ≥40 pack-years]). Age in years and year of questionnaire return were included as stratification variables.