Association between dietary B vitamin intakes and advanced cardiovascular-kidney-metabolic syndrome: insights from the National Health and Nutrition Examination Survey and an external hospital-based dataset.

BACKGROUND: Advanced cardiovascular-kidney-metabolic (CKM) syndrome is highly prevalent. Diet is increasingly considered as a modifiable risk factor for advanced CKM syndrome. This study aims to evaluate the associations of B vitamin intakes with advanced CKM syndrome. METHODS: A cross-sectional study was performed on participants in 2011 to 2020 National Health and Nutrition Examination Survey. Participants were categorized into five CKM stages (0-4) according to the different clinical severities of CKM syndrome, with stages 3 and 4 considered advanced. B vitamin intakes were assessed through two 24-h dietary recall interviews. Multivariable weighted logistic regression, restricted cubic spline analysis, weighted quantile sum (WQS) regression and quantile-based g-computation (QG-comp) were used to explore the associations of single B vitamin intake and mixed B vitamin intakes with advanced CKM syndrome. The primary findings were then externally validated in an independent Chinese cohort. RESULTS: A total of 14,576 CKM syndrome patients were included in the final analysis, of which 2,486 were categorized into advanced CKM syndrome. Multivariable weighted logistic regression showed that higher intakes of vitamin B2 (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.81-0.93) and B6 (OR, 0.88; 95% CI, 0.82-0.95) were associated with a lower likelihood of advanced stages in CKM syndrome patients. Meanwhile, WQS regression and QG-comp analyses consistently indicated a negative association between mixed B vitamin intakes and advanced CKM syndrome, highlighting that vitamin B2 and vitamin B6 were the most significant factors driving the overall effect. These associations were consistently replicated in the external validation cohort. CONCLUSION: Higher intakes of mixed B vitamins were associated with lower risk of advanced CKM syndrome, with vitamin B2 and vitamin B6 emerging as the primary contributors.