Fish consumption and risk of stroke and its subtypes: accumulative evidence from a meta-analysis of prospective cohort studies

INTRODUCTION Fish consumption has been hypothesized to be associated with a reduced risk of stroke, but epidemiological studies showed inconsistent results and most of them have not separated ischemic stroke [...]
BACKGROUND/OBJECTIVES: To provide a reliable assessment of the hypothesized association of fish consumption with stroke risk accumulatively, an updated meta-analysis of published prospective cohort studies was conducted. SUBJECTS/METHODS: Prospective cohort studies through April 2012 in peer-reviewed journals indexed in MEDLINE and EMBASE were selected. Additional information was retrieved through Google or a search of the reference list in relevant articles. The main outcome measure was the weighted hazards ratio (HR) and corresponding 95% confidence interval (CI) for incident stroke according to fish consumption using a random-effects model. RESULTS: A database was derived from 16 eligible studies (19 cohorts), including 402 127 individuals (10 568 incident cases) with an average 12.8 years of follow-up. Compared with those who never consumed fish or ate fish < 1/month, the pooled adjusted HRs of total stroke risk were 0.97 (95% CI, 0.87-1.08), 0.86 (0.80-0.93), 0.91 (0.85-0.98) and 0.87 (0.79-0.96) for those who consumed fish 1-3/month, 1/week, 2-4/week and ≥ 5/week, respectively ([P.sub.linear trend] = 0.09; [P.sub.nonlinear trend] = 0.02). Study location was a modifier. An inverse association between fish intake and stroke incidence was only found by studies conducted in North America. The modest inverse associations were more pronounced with ischemic stroke and were attenuated with hemorrhagic stroke. CONCLUSIONS: Accumulated evidence generated from this meta-analysis suggests that fish intake may have a protective effect against the risk of stroke, particularly ischemic stroke. doi: 10.1038/ejcn.2012.133; published online 3 October 2012 Keywords: fish; stroke; cohort studies; meta-analysis