The associations between coffee consumption timing patterns and metabolic syndrome: the National Health and Nutrition Examination Survey (NHANES), 2003-2018

Evidence on the association between coffee consumption timing patterns and metabolic syndrome (MetS) prevalence remains limited. This cross-sectional study analyzed data from 11632 participants aged 20 years or older in eight National Health and Nutrition Examination Survey (NHANES) cycles (2003-2018), to examine how coffee consumption timing patterns and their combination with coffee amount relate to MetS. Coffee consumption timing patterns were identified using K-means clustering. Two timing patterns were identified: morning-concentrated and evenly distributed. Survey-weighted logistic regression was used to examine associations between timing patterns and MetS prevalence, adjusting for sociodemographic, lifestyle, and dietary covariates. The morning-concentrated pattern was significantly associated with lower prevalence of MetS (OR: 0.80, 95% CI: 0.68, 0.96) compared with non-drinkers, while the evenly distributed pattern showed no significant association. Results were robust across multiple sensitivity analyses. Combined analysis revealed that the morning-concentrated pattern was consistently associated with lower MetS prevalence across all intake levels. Stratified analyses showed stronger inverse associations among women, individuals with normal weight/underweight or overweight, and those aged ≤ 40 years, with significant effect modification by body mass index (BMI; P for interaction < 0.001) and age ( P for interaction = 0.006) groups. These observational findings suggest that the timing of coffee consumption, particularly the morning-concentrated pattern, may be inversely associated with MetS prevalence.