Cross-sectional analyses between the dietary index for gut microbiota and Parkinson's disease in the middle-aged and elderly population.

Background: The evidence linking dietary indices to Parkinson's disease (PD) risk remains limited. This study investigated the association between the Dietary Index for Gut Microbiota (DI-GM) and PD risk in middle-aged and elderly populations.

Methods: Cross-sectional data were obtained from the 2007-2020 cycles of the National Health and Nutrition Examination Survey (NHANES), including 17,373 participants aged 40 years or older. PD was defined by antiparkinsonian medication use. DI-GM scores were calculated based on 14 dietary components. Multiple logistic regression and a restricted cubic spline model (RCS) were used to test the relationship between DI-GM and PD. Subgroup and sensitivity analyses were conducted to evaluate the robustness of the results.

Results: Among 17,373 participants, those with PD (n = 232) had lower DI-GM scores compared to non-PD individuals. Higher DI-GM scores (≥ 6) were associated with a 49% reduction in PD prevalence. RCS analysis showed a non-linear relationship between DI-GM and PD (P < 0.05). Subgroup and sensitivity analyses confirmed stable associations across demographic groups and after adjusting for comorbidities.

Conclusions: A gut microbiota-friendly diet, as measured by DI-GM, is associated with reduced PD risk, especially in the higher DI-GM score. This finding may inform future dietary guidelines for the prevention of PD.