Abstract
BACKGROUND: In recent years, the impact of diet and lifestyle on coronary heart disease (CHD) has garnered significant attention. Caffeine, a common dietary component, and its metabolites may influence cardiovascular health. OBJECTIVE: This study aimed to investigate the association between urinary levels of caffeine and its metabolites and the incidence of CHD as well as to assess how these associations vary across different population groups. METHODS: Data from the NHANES database (2009-2014) were analyzed using multivariable logistic regression models and smooth curve fitting techniques. Participants were categorized into a control group (n = 5,005) and a CHD group (n = 222) based on CHD status. Urinary levels of caffeine and its metabolites were measured and recorded. Multivariable logistic regression was used to evaluate the association between urinary caffeine/metabolite levels and CHD incidence, while smooth curve fitting was employed to explore potential nonlinear relationships. A significance level of 5% was used to determine statistical significance. RESULTS: Higher urinary paraxanthine levels were associated with a lower risk of CHD. In contrast, elevated urinary caffeine levels were positively associated with CHD incidence among Mexican Americans, an association not observed in other racial/ethnic groups. CONCLUSION: Lower urinary paraxanthine levels may reflect a reduced risk of CHD, while higher urinary caffeine levels could indicate an increased CHD risk in specific populations.