Foods and Dietary Intakes and the Risk of Parkinson's Disease: A Systematic Review and Dose-Response Meta-analysis of Prospective Cohort Studies.

CONTEXT: Evidence suggests a link between diet and Parkinson's disease (PD).

OBJECTIVE

We conducted a dose-response meta-analysis of prospective cohort studies to examine the association of food-group intakes and dietary patterns with PD incidence.

DATA SOURCES: After searching PubMed, Scopus, and Web of Science, 29 cohort studies with 1 307 337 participants met the eligibility criteria.

DATA EXTRACTION: Quantitative exposure levels and the most adjusted risk estimates and 95% CIs were extracted.

DATA ANALYSIS: Linear and nonlinear dose-response analyses and highest vs lowest intake comparisons were conducted using STATA and RevMan. Risk of bias was assessed by the Newcastle-Ottawa quality-assessment tool.

RESULTS

Dairy, low-fat dairy, milk, and cheese indicated a positive dose-response association with PD risk. High consumption of dairy, low-fat dairy, and milk demonstrated 26% (odd ratio [OR], 1.26; 95% CI, 1.12-1.41), 30% (OR, 1.30; 95% CI, 1.06-1.58), and 23% (OR, 1.23; 95% CI, 1.07-1.43) increased PD risk compared with the lowest intake categories, respectively. Linear dose-response analysis showed a 5%-7% increased risk for every 100-g/day dairy and low-fat dairy intake, 4% increased risk per 10-g cheese/day, and 13% increased risk per 1 cup milk/day. Sex-based subgroup analysis revealed stronger associations in men for dairy and, to a lesser extent, for low-fat dairy, milk, yogurt, and cheese. Legumes/nuts were the only group that showed a reduced PD risk (OR, 0.71; 95% CI, 0.62-0.81). Both healthy and unhealthy dietary patterns showed dose-response associations with PD risk. Also, in the highest vs lowest comparison, adherence to healthy diets was associated with a 37% reduction in PD risk (OR, 0.63; 95% CI, 0.54-0.74), while adherence to unhealthy diets was linked to a 40% increased PD risk (OR, 1.40; 95% CI, 1.07-1.83).

CONCLUSION

These findings underscore the importance of diet in the prevention or development of PD. While adherence to healthy diets was associated with reduced PD risk, dairy consumption, despite being part of healthy diets, was linked to increased risk, highlighting the need for more nuanced dietary guidance.

SYSTEMATIC REVIEW REGISTRATION: PROSPERO no. CRD420251026654.