Table 1

Characteristics of studies included in the meta-analysis of α-linolenic acid intake and prostate cancer

Study	Country of origin	Study design	Sample size	Age (years)	Incident cases	Follow-up (years)	Exposure level (g/day)	Relative risk or odds ratio	95% CI
Andersson et al 48	Sweden	Case–control	526 cases/536 controls	<80	–	–	0.817–1.35	0.93	0.65 to 1.32
Meyer et al49	Canada	Case–control	215 cases/593 controls	≥45	–	–	–	0.98	0.54 to 1.78
Schuurman et al 20*	The Netherlands	Nested case-cohort	58279 (1525 subcohort)	55–69	642	6.3	0.7–2.1	0.76	0.66 to 1.04
De Stefani et al 32	Uruguay	Case–control	217 cases/431 controls	40–89	–	–	≤0.8 to ≥1.5	3.91	1.50 to 10.1
Ramon et al45	Spain	Case–control	217 cases/434 controls	<60–80	–	–	0.72–2.1	3.1	2.2–4.7
Mannisto et al 24*	Finland	Nested case–control	198 cases/198 controls	50–69	246	5–8	1.0–2.3	1.16	0.64 to 2.13
Bidoli et al 50	Italy	Case–control	1294 cases/1451 controls	45–74	–	–	mean 1.6	0.7	0.6 to 0.9
Koralek et al 22*	USA	Prospective cohort	29592	55–74	1898	5.1	1.09–1.75	0.94	0.81 to 1.09
Hedelin et al51	Sweden	Case–control	1499 cases/1130 controls	mean 67.3	–	–	0.05–0.60	1.35	0.99 to 1.84
Giovannucci et al 21*	USA	Prospective cohort	47750	40–75	3544	16	<0.79 to ≥1.32	1.12	1.01 to 1.25
Park et al19 *	USA	Prospective cohort	82483	≥45	4404	8	1.1–2.14†	0.92	0.84 to 1.02
Williams et al 52	USA	Case–control	79 cases/187 controls	≥18	–	–	≤1.0–4.156†	0.82	0.41 to 1.65