Association of ultra-processed food consumption with prodromal, incident Parkinson's disease and mortality.

Background: Ultra-processed foods (UPFs), widely consumed globally, are increasingly recognised as a key factor in poor dietary quality and diet-related health risks. However, little is known about the role of UPF consumption in the development and progression of Parkinson's disease (PD).

Methods: We followed 121 440 participants who were free of cancer, PD and dementia at baseline, each completing at least two 24-hour dietary assessments. UPF consumption was defined according to the Nova classification. Eight prodromal features were identified through self-reported diagnoses, hospital admission records and primary care data. Prodromal PD was defined as the presence of ≥3 prodromal PD features. Incident PD cases were identified through linkages with hospital admissions, death registers and self-reported data. Information on vital status, date of death and cause of death was obtained from the UK National Health Service (NHS) and the NHS Central Register. The multivariable Cox proportional hazards models were used to estimate the HRs and 95% CIs.

Results: During a median of 10.5 years of follow-up, 1047 participants had ≥3 prodromal PD features, 640 participants developed PD and 114 participants died from PD. Comparing extreme quartiles of UPF consumption, the HRs were 1.65 (95% CI: 1.35 to 2.02) for having ≥3 versus 0 prodromal PD features, 1.32 (95% CI: 1.02 to 1.71) for developing PD and 3.11 (95% CI: 1.56 to 6.17) for PD death (p value trend <0.05 for all).

Conclusions: In this large prospective cohort study, higher UPF consumption was associated with higher risk of developing prodromal PD, incident PD and PD-specific mortality.