Fish consumption and risk of myeloma: a meta-analysis of epidemiological studies

The relationship between fish consumption and multiple myeloma (MM) risk has not been consistent across epidemiological studies. We quantitatively assessed the aforementioned association through a systematic review and meta-analysis. PubMed was searched through the end of March 2015 for eligible studies. Fixed or random effects models were used to pool risk estimates. Five case-control studies that involved 1,366 cases and 8,259 controls were identified. Three studies had high methodological quality, and two studies had low quality based on the Newcastle-Ottawa Quality Assessment Scale. After pooling all risk estimates, a significant inverse association was found between the highest category versus lowest category of fish consumption and MM risk (relative risk = 0.65, 95 % confidence interval = 0.46-0.91), with relatively high heterogeneity (I (2) = 55.6 %). No evidence of publication bias was detected. The inverse association persisted in all subgroups according to study quality, type, location, and whether there were adjustments for confounders, although statistical significance was not detected in all strata. The dose-response analysis suggested a nonlinear dose-response relationship for the association, with the lowest risk linked to fish consumption once per week. This meta-analysis suggests that the highest versus lowest category of fish consumption is inversely associated with MM risk. Furthermore, a nonlinear dose-response relationship was suggested for the association. Because this evidence is based on a small number of retrospective studies with mixed quality and because high heterogeneity was detected, further prospective studies are warranted to validate our findings and better characterize the relationship.