Case-control and prospective studies of dietary α-linolenic acid intake and prostate cancer risk: a meta-analysis.

Content Provider	Europe PMC
Author	Carleton, Amanda J Sievenpiper, John L de Souza, Russell McKeown-Eyssen, Gail Jenkins, David J A
Copyright Year	2013
Abstract	Objectiveα-Linolenic acid (ALA) is considered to be a cardioprotective nutrient; however, some epidemiological studies have suggested that dietary ALA intake increases the risk of prostate cancer. The main objective was to conduct a systematic review and meta-analysis of case–control and prospective studies investigating the association between dietary ALA intake and prostate cancer risk.DesignA systematic review and meta-analysis were conducted by searching MEDLINE and EMBASE for relevant prospective and case–control studies.Included studiesWe included all prospective cohort, case–control, nested case-cohort and nested case–control studies that investigated the effect of dietary ALA intake on the incidence (or diagnosis) of prostate cancer and provided relative risk (RR), HR or OR estimates.Primary outcome measureData were pooled using the generic inverse variance method with a random effects model from studies that compared the highest ALA quantile with the lowest ALA quantile. Risk estimates were expressed as RR with 95% CIs. Heterogeneity was assessed by χ2 and quantified by I2.ResultsData from five prospective and seven case–control studies were pooled. The overall RR estimate showed ALA intake to be positively but non-significantly associated with prostate cancer risk (1.08 (0.90 to 1.29), p=0.40; I2=85%), but the interpretation was complicated by evidence of heterogeneity not explained by study design. A weak, non-significant protective effect of ALA intake on prostate cancer risk in the prospective studies became significant (0.91 (0.83 to 0.99), p=0.02) without evidence of heterogeneity (I2=8%, p=0.35) on removal of one study during sensitivity analyses.ConclusionsThis analysis failed to confirm an association between dietary ALA intake and prostate cancer risk. Larger and longer observational and interventional studies are needed to define the role of ALA and prostate cancer.
Journal	BMJ Open
Volume Number	3
PubMed Central reference number	PMC3657642
Issue Number	5
PubMed reference number	23674441
e-ISSN	20446055
DOI	10.1136/bmjopen-2012-002280
Language	English
Publisher	BMJ Publishing Group
Publisher Date	2013-05-14
Publisher Place	London
Access Restriction	Open
Rights License	This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/3.0/ and http://creativecommons.org/licenses/by-nc/3.0/legalcode Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions
Subject Keyword	Nutrition & Dietetics Preventive Medicine
Content Type	Text
Resource Type	Article
Subject	Medicine