Coffee Consumption Correlates With Better Cognitive Performance in Patients With a High Incidence for Stroke

Abstract

Background: Atrial fibrillation is an independent risk factor for the development of cognitive impairments. Regular coffee consumption has shown cognitive benefits in healthy individuals. Whether regular consumption reduces cognitive decline in vulnerable patients is controversial. We investigated the association in elderly people with atrial fibrillation.

Methods and results: Daily coffee consumption was assessed using a structured nutrition questionnaire, and cognitive function was evaluated by a detailed neurocognitive-test-battery, including the Montreal Cognitive Assessment, Trail-Making Test, semantic fluency, and Digit-Symbol-Substitution Test. The cognitive construct score combines all neurocognitive tests mentioned and provides an overall cognitive performance indicator. Hs-CRP (high-sensitivity C-reactive protein) and IL-6 (interleukin-6) were measured to explore an association with inflammation. Results were estimated using linear mixed-effects-models with detailed adjustments for confounders. The <1 cup/day consumers (reference group) reached a cognitive construct score of -0.24 (95% CI, -0.27 to -0.16), and the group with the highest consumption (>5 cups/day) was at -0.10 (95% CI, -0.10 to 0.04; p=0.048). Montreal Cognitive Assessment score in the reference group was 24.58 (95% CI, 24.58-25.32); the group with the highest intake achieved 25.25 (95% CI, 24.98-26.85; p=0.163). Inflammatory markers decreased with higher coffee consumption (hs-CRP with 5 compared with <1 cup/day by factor 0.78 [95% CI, 0.54-1.13], p= 0.188, IL-6 significantly by factor 0.73 [95% CI, 0.57-0.95], p=0.017).

Conclusions: Coffee consumption in patients with atrial fibrillation may be associated with improved cognitive performance and reduced inflammatory markers. Further research is needed to confirm these findings and to consider implementation in dietary counseling for atrial fibrillation management.

Registration: URL: https://www.clinicaltrials.gov; Identifier: NCT02105844.

Keywords: atrial fibrillation; coffee; cognitive function; inflammation; vascular dementia.

Figure 1. Primary outcomes.

CoCo score as aggregated global performance parameter. A, Boxplot visualizing unadjusted scores subdivided in different coffee consumer groups. B, Estimates of adjusted CoCo scores indicating differences between coffee consumer groups and the reference group (<1 cup of coffee per day) indicating higher cognitive performance with higher coffee consumption and showing the P value for trends. C, Boxplot visualizing unadjusted MoCA in different coffee consumer groups. D, Estimates of adjusted MoCA scores and P value for trends. The data provide the evidence of a persistent significance of the caffeine effect on cognitive function after extensive adjustments for the following confounders: Current coffee consumption, age, sex, education, body mass index, smoking status, physical activity, presence of depression, arterial hypertension, medication with anticoagulants, diabetes type 2, and history of stroke, as well as high‐sensitivity C‐reactive protein, and interleukin‐6 levels. CoCo indicates cognitive construct; and MoCA, Montreal cognitive assessment score.

Figure 2. Same pattern in the DSST and the SF scores; particularly the DSST demonstrates a strong and dose‐dependent association.

Secondary outcomes: Cognitive subtests performed within the Swiss‐AF study. A, Boxplot visualizing unadjusted DSST scores. B, Estimates of adjusted DSST scores and P value for trends. C, Boxplot of unadjusted SF scores in different coffee consumer groups. D, Estimates of adjusted SF scores and P value for trends. The data collectively indicate a significant effect of coffee consumption in the DSST and SF test, which remained significant after adjustments in the DSST and in the larger subgroups in the SF test. Adjusting covariates: Current coffee consumption, age, sex, education, body mass index, smoking status, physical activity, presence of depression, arterial hypertension, medication with anticoagulants, diabetes type 2, and history of stroke, as well as high‐sensitivity C‐reactive protein and interleukin‐6 levels. DSST indicates Digit Symbol Substitution Test; SF, semantic fluency; and Swiss‐AF, Swiss Atrial Fibrillation Cohort Study.

Figure 3. A similar pattern can be observed in the TMT‐A and TMT‐B test, which reach significance with 4 to 5 cups in TMT‐B.

Secondary outcomes: Boxplot of unadjusted (A) TMT‐A and (B) TMT‐B scores in different coffee consumption groups and P value for trends. Estimates indicating differences of (C) TMT‐A and (D) TMT‐B between coffee consumer groups and reference groups (<1 cup of coffee per day) and P value for trends, adjusted for the aforementioned variables. The data collectively shows a significant association in TMT‐A and ‐B and its persistence in TMT‐B in the highest coffee consumption groups after extensive adjustments. Adjusting covariates: Current coffee consumption, age, sex, education, body mass index, smoking status, physical activity, presence of depression, arterial hypertension, medication with anticoagulants, diabetes type 2, and history of stroke, as well as high‐sensitivity C‐reactive protein and interleukin‐6 levels. TMT indicates Trial Making Test.

Figure 4. Inflammatory parameters.

Inflammatory parameters in association to coffee consumption. A, Boxplot visualizing unadjusted log(hs‐CRP) concentration in different coffee consumer groups. B, Estimates of adjusted log(hs‐CRP) concentrations and P value for trends. C, Boxplot of unadjusted log(IL‐6) concentrations. D, Estimates of adjusted log(IL‐6) concentrations and P value for trends. Association between dose‐dependent coffee consumption and preserved cognitive function in patients with AF: As possible protective mechanism, an anti‐inflammatory effect is detectable. Further, in literature described effects are listed. Using polynomial contrast, the linear trend estimate of coffee consumption on log(hs‐CRP) was −0.18 (95% CI, –0.43 to 0.06; P=0.14) and on log(IL‐6) –0.2 (95% CI, –0.37 to −0.04; P=0.02). Adjusting covariates: Current coffee consumption, age, sex, education, body mass index, smoking status, physical activity, presence of depression, arterial hypertension, medication with anticoagulants, diabetes type 2, and history of stroke. AF indicates atrial fibrillation; hs‐CRP, high‐sensitivity C‐reactive protein; and IL‐6, interleukin‐6.

Figure 5. Pathophysiology.

It illustrates the strong association of increasing coffee consumption in patients with atrial fibrillation with the performance in global (eg, CoCo) and specific (eg, DSST) cognitive testing. Further, an inverse association with the inflammatory markers hs‐CRP and IL‐6 is observed. Created with Biorender.com. CoCo indicates cognitive construct; and DSST, Digit Symbol Substitution Test.