BACKGROUND: The intestinal microbiota critically modulates physiological status and is shaped by nutritional intake. This research explored the correlation between the dietary index for gut microbiota (DI-GM) and premature death and all-cause mortality, focusing on the mediating effect of biological age.
METHODS: The longitudinal study drew upon information gathered from the National Health and Nutrition Examination Survey (NHANES) spanning 2007-2018, with mortality data linked through 2019. DI-GM scores derived from nutritional values. Premature death and all-cause mortality were the primary endpoints. Biological age was assessed using PhenoAge (PA), the Klemera-Doubal Method (KDMAge), and homeostatic dysregulation (HD). The correlation between DI-GM and mortality was analyzed through Kaplan-Meier curves, Cox regression, smooth curve fitting, subgroup analysis, and mediation analysis.
RESULTS: The study comprised 15,810 participants (mean age: 47.0 ± 15.7 years; 49.3% male). Multivariable Cox regression revealed that each DI-GM point rise correlated with 9% fewer premature deaths and 10% lower total mortality. Smooth curve fitting showed a clear inverse linear correlation between DI-GM scores and both premature and total mortality, consistent across subgroups. Mediation analysis revealed that biological age partially mediates this association.
CONCLUSION: Elevated DI-GM scores were associated with a lower premature death and all-cause mortality, with biological aging serving as a significant mediator in this relationship.
Longevity & Aging