Mercury exposure and risk of cardiovascular disease: a nested case-control study in the PREDIMED PREvention with MEDiterranean Diet studyReport as inadecuate

Mercury exposure and risk of cardiovascular disease: a nested case-control study in the PREDIMED PREvention with MEDiterranean Diet study - Download this document for free, or read online. Document in PDF available to download.

BMC Cardiovascular Disorders

, 17:9



BackgroundSubstantial evidence suggests that consuming 1–2 servings of fish per week, particularly oily fish e.g., salmon, herring, sardines is beneficial for cardiovascular health due to its high n-3 polyunsaturated fatty acid content. However, there is some concern that the mercury content in fish may increase cardiovascular disease risk, but this relationship remains unclear.

MethodsThe PREDIMED trial included 7477 participants who were at high risk for cardiovascular disease at baseline. In this study, we evaluated associations between mercury exposure, fish consumption and cardiovascular disease. We randomly selected 147 of the 288 cases diagnosed with cardiovascular disease during follow-up and matched them on age and sex to 267 controls. Instrumental neutron activation analysis was used to assess toenail mercury concentration. In-person interviews, medical record reviews and validated questionnaires were used to assess fish consumption and other covariates. Information was collected at baseline and updated yearly during follow-up. We used conditional logistic regression to evaluate associations in the total nested case-control study, and unconditional logistic regression for population subsets.

ResultsMean ±SD toenail mercury concentrations μg per gram did not significantly differ between cases 0.63 ±0.53 and controls 0.67 ±0.49. Mercury concentration was not associated with cardiovascular disease in any analysis, and neither was fish consumption or n-3 fatty acids. The fully-adjusted relative risks for the highest versus lowest quartile of mercury concentration were 0.71 95% Confidence Interval CI, 0.34, 1.14; ptrend = 0.37 for the nested case-control study, 0.74 95% CI, 0.32, 1.76; ptrend = 0.43 within the Mediterranean diet intervention group, and 0.50 95% CI, 0.13, 1.96; ptrend = 0.41 within the control arm of the trial. Associations remained null when mercury was jointly assessed with fish consumption at baseline and during follow-up. Results were similar in different sensitivity analyses.

ConclusionsWe found no evidence that mercury exposure from regular fish consumption increases cardiovascular disease risk in a population of Spanish adults with high cardiovascular disease risk and high fish consumption. This implies that the mercury content in fish does not detract from the already established cardiovascular benefits of fish consumption.

Trial registrationISRCTN35739639.

KeywordsMercury Fish Cardiovascular disease Mediterranean diet PREDIMED Toenail biomarker AbbreviationsBMIBody mass index

CHDCoronary heart disease

DHADocosahexaenoic acid

EPAEicosapentaenoic acid

INAAInstrumental neutron activation analysis


OROdds ratio

PREDIMEDPREvención con DIeta MEDiterránea Prevention with Mediterranean diet

PUFAPoly-unsaturated fatty acids

Electronic supplementary materialThe online version of this article doi:10.1186-s12872-016-0435-8 contains supplementary material, which is available to authorized users.

Download fulltext PDF

Author: Mary K. Downer - Miguel A. Martínez-González - Alfredo Gea - Meir Stampfer - Julia Warnberg - Miguel Ruiz-Canela - Jordi


Related documents