Cross-sectional associations between urinary caffeine metabolites and osteoarthritis prevalence in US adults: National Health and Nutrition Examination Survey (NHANES) 2009–2014

AimThis study aims to investigate the cross-sectional associations of caffeine-related metabolites with prevalent osteoarthritis (OA).MethodsThe study comprised 4583 US adults from 2009-2014 National Health and Nutrition Examination Survey, who had data on urinary caffeine-related metabolites and responded to the questions, "doctor ever said you had arthritis?" and "which type of arthritis was it?" Logistic regressions were used to examine the association between each metabolite and OA prevalence after considering the complex design and adjusting for age, sex, race, body mass index (BMI), household income, smoking status, and alcohol consumption. To assess the joint association of individual metabolites, a composite metabolomic score was constructed from principal component analysis.ResultsAmong the study sample, 653 adults were reported to have OA. The OA cases were more likely to be older, female, non-Hispanic White, never smokers, and have higher BMI. The majority of caffeine-related metabolites showed positive associations with prevalent OA in unadjusted models, but these associations were attenuated to null in multivariable-adjusted models. In further exploratory stratified analyses, higher levels of 3-methyluric acid, 7-methyluric acid, 3,7-dimethyluric acid, 3-methylxanthine, and 7-methylxanthine were associated with a higher prevalence of OA in women, but not in men. Similarly, a significant positive association was observed between the composite metabolomic score and OA in women but not in men.ConclusionIn this cross-sectional study, certain caffeine-related metabolites were positively associated with the prevalence of OA in women. Well-designed cohort studies are needed to investigate the association of caffeine consumption and related metabolites with OA risk.