“The effects of coffee consumption on SUA levels and gout risk are controversial,” investigators explained. “There have hitherto been no reports based on its effects that consider pleiotropy.”
When pleiotropy was accounted for, Mendelian randomization (MR) analyses concluded that gout risk was reduced with coffee consumption independently of serum uric acid (SUA) levels, according to a study published in Open Rheumatology.1
“The effects of coffee consumption on SUA levels and gout risk are controversial,” investigators explained. “There have hitherto been no reports based on MR analysis of its effects that consider pleiotropy.”
Investigators conducted a series of MR analyses of the Japanese population focusing on the effect of coffee consumption on SUA levels regarding gout while considering pleiotropy. The study utilized genome-wide association study (GWAS) summary statistics from 152,634 participants with habitual coffee consumption, 3053 patients with gout, 4554 controls, and 121,745 SUA-level data. An analysis of heterogeneity, with removal of possible pleiotropy cases, was performed in addition to a fixed-effect inverse variance weighted (IVW) meta-analysis. Coffee consumption was defined in cups per day via the Coffee and Caffeine Genetics Consortium (CCGC). R statistical software with the TwoSampleMR package was used for the MR analysis.
Of 10 single nucleotide polymorphisms (SNPs) included, those who reported habitual coffee consumption were significantly inversely associated with gout (odds ratio [OR] = 0.29, 95% confidence interval [95% CI]: 0.16-0.51, P = 1.9 × 10−5) in IVW analyses.
Further, 3 more instruments suspected to have a pleiotropic effect on gout were excluded. The analysis of the remaining instruments also supported the findings that coffee was inversely associated with gout (OR = 0.75, 95% CI: 0.58-0.97, P = 0.026) without heterogeneity (Phet = 0.39). No significant differences were observed between coffee consumption and SUA levels regarding ancestry (Phet = 2.0 × 10−16 in Japanese and Phet = 6.8 × 10−8 in Europeans).
Multivariable analysis similarly solidified the theory that increased coffee consumption significantly reduced risk of gout, even after adjusting for the SUA levels (OR = 0.50, 95% CI: 0.31-0.81, P = 0.0046). This research further suggests that the consumption of coffee has protective effects on the progression of asymptomatic hyperuricemia to gout.
The exposure was calculated by the number of days per week participants drank coffee, as was available via the questionnaire, which may have limited the study and disjointed outcome effects. Additional research needs to be conducted to understand the ways in which coffee protects against developing gout.
“Although the impact on SUA levels is still ambiguous, obvious protective effects of habitual coffee consumption on gout risk were observed,” investigators concluded. “We consider that coffee consumption may reduce gout risk independently of SUA levels. Our study suggests the presence of biological pathways involved in gout pathogenesis other than SUA levels and should contribute to the development of preventive medicine against gout.”
Shirai, Y., 2022. Coffee Consumption Reduces Gout Risk Independently of Serum Uric Acid Levels: Mendelian Randomization Analyses Across Ancestry Populations. [online] ACR Open Rheumatology. Available at: <https://onlinelibrary.wiley.com/doi/full/10.1002/acr2.11425> [Accessed 29 March 2022].