Background
The aim of the present meta-analysis of cohort studies was to focus on monounsaturated
fat (MUFA) and cardiovascular disease, cardiovascular mortality as well as all-cause
mortality, and to distinguish between the different dietary sources of MUFA.
Methods
Literature search was performed using the electronic databases PUBMED, and EMBASE
until June 2nd, 2014. Study specific risk ratios and hazard ratios were pooled using
a inverse variance random effect model.
Results
Thirty-two cohort studies (42 reports) including 841,211 subjects met the objectives
and were included. The comparison of the top versus bottom third of the distribution
of a combination of MUFA (of both plant and animal origin), olive oil, oleic acid,
and MUFA:SFA ratio in each study resulted in a significant risk reduction for: all-cause
mortality (RR: 0.89, 95% CI 0.83, 0.96, p = 0.001; I2 = 64%), cardiovascular mortality
(RR: 0.88, 95% CI 0.80, 0.96, p = 0.004; I2 = 50%), cardiovascular events (RR: 0.91,
95% CI 0.86, 0.96, p = 0.001; I2 = 58%), and stroke (RR: 0.83, 95% CI 0.71, 0.97,
p = 0.02; I2 = 70%). Following subgroup analyses, significant associations could only
be found between higher intakes of olive oil and reduced risk of all-cause mortality,
cardiovascular events, and stroke, respectively. The MUFA subgroup analyses did not
reveal any significant risk reduction.
Conclusion
The results indicate an overall risk reduction of all-cause mortality (11%), cardiovascular
mortality (12%), cardiovascular events (9%), and stroke (17%) when comparing the top
versus bottom third of MUFA, olive oil, oleic acid, and MUFA:SFA ratio. MUFA of mixed
animal and vegetable sources per se did not yield any significant effects on these
outcome parameters. However, only olive oil seems to be associated with reduced risk.
Further research is necessary to evaluate specific sources of MUFA (i.e. plant vs.
animal) and cardiovascular risk.
Electronic supplementary material
The online version of this article (doi:10.1186/1476-511X-13-154) contains supplementary
material, which is available to authorized users.