Effects of coffee consumption on arterial stiffness and endothelial function: a systematic review and meta-analysis of randomized clinical trials

Abstract

Background

Endothelial function (EF) and arterial stiffness (AS) are predictors of cardiovascular disease. As previous research concerning the effect of coffee intake on EF and AS was controversial, we conducted a systematic review and meta-analysis to synthesize research.

Methods

We performed a systematic search in PubMed, Scopus and Web of Science to find clinical trials investigating the effect of coffee intake on EF or AS up to March 2020.Random-effects models were used to estimate the pooled weighted mean difference (WMD) between intervention and control groups for randomized controlled trials (RCTs). Between study heterogeneity was estimated using Cochran’s Q and the I²-inconsistency index. Internal validity of included randomized trials was determined with the Cochrane Collaboration’s tool for assessing the risk of bias.

Results

Twenty-three articles were included for qualitative and 11 articles for quantitative synthesis. Meta-analysis of 14 RCTs (nine articles) indicated a positive short-term (postprandial) effect of coffee intake on flow-mediated dilation (FMD) as a measure of EF (WMD: 1.93%[95% CI: 1.10–2.75]; I²= 97.9%). Meta-analysis of three long-term RCTs(two articles) found no such effect on FMD (WMD: −0.08% [−3.82 to 3.66]; I²= 61.4%).Most short-term information was from studies at low or unclear risk of bias, while the proportion of long-term information from studies at high risk of bias was considerable.

Conclusion

The results from this meta-analysis suggest a beneficial short-term effect of coffee intake on EF as measured by FMD. However, there might be unfavorable effects on AS. Our findings must be interpreted cautiously as the number of studies were low and included studies had a considerable risk of bias.

Keywords:

• Coffee
• caffeine
• arterial stiffness
• endothelial function
• meta-analysis

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Disclosure statement

All authors declare that they have no conflict of interest.

Additional information

Funding

The present systematic review and meta-analysis was supported by Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences (98-02-61-42226).