Dairy and Milk Intake and Risk for Parkinson's Disease in Women and Men: A Systematic Review and Meta-Analysis

Parkinson's disease is the second most common neurodegenerative disorder, with environmental factors influencing the risk. The role of dairy consumption is controversial, despite repeated with Parkinson's disease in epidemiological studies.

We conducted a systematic review and meta-analysis to evaluate sex-specific associations between dairy intake and Parkinson's disease risk.

A literature search was performed using the Medline and EMBASE databases. Out of 649 studies, eight cohort studies were included in the systematic review, covering 578,736 participants and 4816 Parkinson's disease cases from seven countries. For the meta-analyses, a Restricted Maximum Likelihood random effect model was used to derive the pooled estimates stratified by sex for six prospective cohort studies comparing the highest versus the lowest intake quantile. Results revealed a sex-specific effect of dairy intake, a significant association with a higher risk of Parkinson's disease in males (HR 1.28, 1.05-1.56), whereas no association was observed in females (HR 1.02, 0.80-1.30). For milk intake only, estimates were 1.36 (0.97-1.90) for males and 1.19 (0.94-1.51) for females.

Our meta-analysis found an association between dairy consumption and Parkinson's disease risk in males, but not in females. There was also an almost significant association between milk intake and risk of Parkinson's disease, which was stronger in males than in females. However, the evidence for this association remains weak. Further studies with larger sex-stratified samples across diverse countries are needed to clarify sex differences and establish significant associations.