The Association Between Coffee Consumption and Metabolic Syndrome in Adults: A Systematic Review and Meta-Analysis

Abstract

Previous meta-analyses that found an inverse association between coffee consumption and metabolic syndrome pooled data from cross-sectional and longitudinal studies, which could lead to potentially misleading conclusions. Hence, this work aimed to reassess this association by analyzing data from the 2 types of studies separately and including recent studies. Online databases including PubMed, Scopus, Embase, The Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus, and Science Direct were searched for relevant studies published up to July 2020. Both cross-sectional and longitudinal studies were included if published after 1999, reported both effect estimates and CIs, and presented results adjusted for confounding variables. Data of the highest coffee consumption level in each study, as well as those of medium consumption levels in studies with ≥3 consumption categories, were pooled using random-effect models, with sex-stratified and sex-adjusted results being analyzed separately. Results were obtained based on data from 13 cross-sectional studies involving 280,803 participants and 2 longitudinal studies involving 17,014 participants. The overall sex-adjusted association of the highest consumption level was not significant (n = 9 studies; OR: 0.88; 95% CI: 0.70, 1.10; I2: 91.5%) and the 2 longitudinal studies both yielded no association. Subgroup analysis revealed inverse associations in both males and females, as well as in Caucasians with medium coffee consumption (n = 4 studies, OR: 0.88; 95% CI: 0.84, 0.93; I2: 0%). Although residual confounding could affect the results of this meta-analysis, our findings suggested with a low certainty that coffee consumption may not be associated with metabolic syndrome, a finding that is different from those of previous meta-analyses and could be due to variation in characteristics of study participants. More longitudinal studies are also needed to further assess the temporal association between coffee consumption and metabolic syndrome. This meta-analysis was registered at https://www.crd.york.ac.uk/prospero as CRD42018110650.

The longitudinal association between coffee and tea consumption and the risk of metabolic syndrome and its component conditions in an older adult population

“…The lack of a significant longitudinal association between coffee consumption and metabolic syndrome was also observed in previous prospective studies (14)(15)(16) . This also agrees with a recent meta-analysis (13) which did not observe a significant association between coffee consumption and metabolic syndrome. The null findings in this regard also implied that the inverse associations between coffee consumption and T2DM (41) and CVD incidence (42) were not due to improvements in biomarkers, thereby strengthening the argument that residual confounding could be behind these results (43) .…”

“…However, the significant associations between coffee consumption and metabolic syndrome, as well as its component conditions, were only observed in cross-sectional studies (13) , leading to worries that such results could be biased by residual confounding and reverse causation. In support of this statement, longitudinal studies in this regard have only been conducted in younger populations (14)(15)(16) and did not yield any significant findings, while the longitudinal association between tea and coffee consumption and the incidence of metabolic syndrome has not been previously investigated in an elderly population.…”

Coffee Consumption and the Risk of Metabolic Syndrome in the ‘Seguimiento Universidad de Navarra’ Project

“…A recent metanalysis of randomized controlled trials by Ramli et al investigated the effects of coffee consumption on anthropometric measurements, glycemic indices, lipid profiles, and blood pressure and found all of these parameters were improved by green coffee extract supplementation [ 17 ]. It is of great interest to continue to investigate the relationship between coffee consumption and the development of MetS, especially given that there is little prospective epidemiological evidence on the association between coffee consumption and MetS incidence [ 18 ].…”

Health Benefits of Functional Foods

“…The results suggest that the addition of coff ee to a beverage with adequate amounts of carbohydrates increased muscle glycogen re-synthesis and the glycemic and insulinemic response during the 4h recovery after endurance training [46]. Also, preloading with decaff einated coff ee (140 ml) with added milk (50 ml of low fat cow's milk) and sugar (7.5 g) led to a blunted postprandial glycaemic response after consuming a high-glycemic index meal (GI 88) consisting of puff ed rice cereal (30 g), glucose powder (10 g) and rice milk (150 ml) [47]. Finally, similarly to tea, also coff ee intake has been associated with better mental health conditions, with mental analyses showing that drinking 400 ml of coff ee a day may be protective against depression [48].…”