Highlights
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C-reactive protein partially mediates the inverse association between coffee consumption and type 2 diabetes risk : The UK Biobank and Rotterdam Study Cohorts
Summary
Background
Coffee is one of the most consumed drinks worldwide. Coffee consumption has been associated with a lower risk of type 2 diabetes mellitus (T2D), but the underlying mechanisms are not well understood. Our objective was to study the role of classical and novel T2D biomarkers with anti- or pro-inflammatory activity in the association between habitual coffee intake and the risk of T2D. Additionally, we studied differences by coffee types and smoking status in this association.
Methods
Using two large population-based cohorts, the UK-Biobank (UKB; n = 145,368) and the Rotterdam Study (RS; n = 7111), we investigated the associations of habitual coffee consumption with incident T2D and repeated measures of resistance. to insulin (HOMA-IR), using mixed effects and Cox proportional hazards models, respectively.
Additionally, we studied associations between coffee and biomarkers of subclinical inflammation, including C-reactive protein (CRP) and IL-13, and adipokines, such as adiponectin and leptin, using linear regression models.
Next, we conducted formal causal mediation analyzes to investigate the role of coffee-associated biomarkers in the association of coffee with T2D.
Finally, we assessed effect modification by coffee type and smoking status. All models were adjusted for sociodemographic, lifestyle, and health-related factors.
Results
During a median follow-up of 13.9 (RS) and 7.4 (UKB) years, 843 and 2290 incident cases of T2D occurred, respectively. A 1 cup/day increase in coffee consumption was associated with a 4% lower risk of T2D (RS, HR = 0.96 [95% CI: 0.92, 0.99], p = 0.045; UKB, HR = 0.96 [0.94; 0.98], p < 0.001), with lower HOMA-IR (RS, log-transformed β = −0.017 [−0.024; −0.010], p < 0.001) , and with lower CRP (RS, log-transformed β = −0.014 [−0.022;−0.005 ], p = 0.002; UKB, β = −0.011 [−0.012; −0.009], p < 0.001).
We also observed associations of higher coffee consumption with higher serum concentrations of adiponectin and IL-13, and with lower concentrations of leptin.
Coffee-related CRP levels partially mediated the inverse association of coffee intake with T2D incidence (average mediation effect RS β = 0.105 (0.014, 0.240), p = 0.016; UKB β = 6.484 (4.265, 9.339 ), p < 0.001), with a PCR-mediated proportion of 3.7% [−0.012%; 24.4%] (RS) to 9.8% [5.7%; 25.8%] (UKB).
No mediation effect was observed for the other biomarkers. The coffee-T2D and coffee-CRP associations were generally stronger among ground coffee consumers (filtered or espresso) and among never and former smokers.
Conclusions
Lower subclinical inflammation may partially mediate the beneficial association between coffee consumption and lower risk of T2D. Ground coffee drinkers and non-smokers may benefit the most.
Comments
The study published in Clinical Nutrition and funded by the Institute for Scientific Information on Coffee (ISIC) found that coffee consumption may help reduce the risk of type 2 diabetes (T2D), mediated by differences in inflammatory biomarkers in the body. The research evaluated the underlying mechanisms by which coffee consumption may help reduce the risk of T2D and found that lower subclinical inflammation may partially explain the association.
Type 2 diabetes is considered in part an inflammatory disease, so by investigating the effect of coffee on biomarkers of inflammation such as C-reactive protein (CRP), which increases when there is inflammation in the body, the study sought to understand the mechanisms underlying reasons linking higher coffee consumption with lower risk of T2D.
Using data from the UK Biobank (n=145,368) and the Rotterdam Study (n=7,111), researchers confirmed that a one cup per day increase in coffee consumption was associated with a 4-6% lower risk of T2D. It also predicted a possible additional favorable impact, such as lower insulin resistance, lower CRP, lower leptin and higher adiponectin concentrations in the cohort participants. Adiponectin is a hormone that regulates glucose and lipid metabolism, which has been shown to have anti-inflammatory and insulin-sensitizing effects, and leptin is a hormone that regulates food intake and energy homeostasis.
An increase of one cup per day was measured against individuals’ varying daily consumption rather than an established baseline. Daily consumption within the study cohort ranged from 0 to ~6 cups of coffee per day, and the findings suggest the benefits of an additional cup per day, regardless of whether people are at the lower or higher end of that range. .
Data from the UK Biobank cohort also suggested that the way coffee is prepared may affect its health benefits. Filtered coffee or espresso had the strongest beneficial association with lower risk of T2D and CRP concentrations, in addition to being a non-smoker.
The study is authored by a team led by Dr. Trudy Voortman, PhD, Associate Professor of Nutritional Epidemiology at Erasmus University Medical Center Rotterdam, with Dr. Carolina Ochoa-Rosales, PhD, Postdoctoral Scientist at the same institute , as lead author of the study.
Dr. Voortman commented: “Coffee is one of the most frequently consumed beverages worldwide and its potential health effects trigger significant scientific research. Previous studies have linked higher coffee consumption to a lower risk of developing T2D, but the underlying mechanisms remain unclear. Our research shows that coffee is associated with differences in the levels of inflammation biomarkers in the body, and as we know that T2D is in part an inflammatory disease, this could be one of the mechanisms at play. “These findings could also support future research on the effects of coffee on other chronic diseases related to inflammation.”
The research complements the existing body of evidence on the association between coffee consumption and reduced risk of T2D, which may contribute to the development of guidance on how nutrition and lifestyle changes support disease reduction strategies. non-transmissible like T2D.
This research study, ’C-reactive protein partially mediates the inverse association between coffee consumption and risk of type 2 diabetes: the UK Biobank and Rotterdam study cohorts’ was first presented at the ASN Nutrition 2021 and at the Epi-Lifestyle 2021 Scientific Sessions hosted by the American Heart Association, where she was awarded the 2021 Paul Dudley White International Scholar Award.
