Independent interacting effects of folate and methylmalonic acid on cardiovascular disease mortality

ABSTRACT: Objective: To investigate the independent and interactive effects of circulating folate and methylmalonic acid (MMA) status on cardiovascular disease (CVD) mortality. Methods: This study included 22,487 individuals from the U.S. National Health and Nutrition Examination Survey (NHANES) between 1999 and 2014. Kaplan-Meier and weighted Cox proportional hazards models were used to assess the associations of folate and MMA with CVD mortality. Restricted cubic splines (RCS) evaluated nonlinear relationships. Additive interaction method explored interactive effects. Sensitivity analysis tested the robustness of the findings. In vitro, CCK-8 assays were performed to assess the combined effects of folate and MMA on H9c2 cardiomyocyte viability. Transcriptomic analysis identified differentially expressed genes (DEGs) and their enriched pathways. Results: During 12.1 years of median follow-up, 1,510 cardiovascular deaths (4.4%) were recorded. RCS analysis demonstrated a U-shaped association between folate levels and CVD mortality, and a linear association for MMA. When MMA ≤ 182 nmol/L, folate levels were not associated with CVD mortality. However, among individuals with MMA > 182 nmol/L, both low and high folate levels were significantly associated with higher CVD mortality, with adjusted hazard ratios (aHRs) of 1.43 (95% CI: 1.19-1.71) and 2.36 (95% CI: 1.85-3.00), respectively (both P < 0.001). An additive interaction between folate and MMA on CVD mortality (RERI: 0.82 [95% CI: 0.06-1.58], API: 0.35 [95% CI: 0.03-0.67]; SI: 1.57 [95% CI: 1.27-2.00]). Sensitivity analyses confirmed these findings. In vitro, MMA (8 mM) significantly enhanced folate-induced (1.6 mM) cytotoxicity, reducing cell viability to 49.26% (P < 0.001). Transcriptomic analysis revealed 53 DEGs under combined treatment, enriched in inflammation-related pathways. Conclusions: Both population-based and experimental evidence suggest that elevated folate and MMA levels independently increase CVD mortality risk, with their interaction synergistically exacerbating cardiovascular outcomes.

ORGANISM(S): Rattus norvegicus

PROVIDER: GSE307146 | GEO | 2025/11/02

REPOSITORIES: GEO