Dairy intake and Parkinson's disease: a mendelian randomization study

Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease (Courage-PD) Consortium, Cloé Domenighetti, Pierre-Emmanuel Sugier, Ashwin Ashok Kumar Sreelatha, Claudia Schulte, Sandeep Grover, Océane Mohamed, Berta Portugal, Patrick May, Dheeraj R Bobbili, Milena Radivojkov-Blagojevic, Peter Lichtner, Andrew B Singleton, Dena G Hernandez, Connor Edsall, George D Mellick, Alexander Zimprich, Walter Pirker, Ekaterina Rogaeva, Anthony E LangSulev Koks, Pille Taba, Suzanne Lesage, Alexis Brice, Jean-Christophe Corvol, Marie-Christine Chartier-Harlin, Eugénie Mutez, Kathrin Brockmann, Angela B Deutschländer, Georges M Hadjigeorgiou, Efthimos Dardiotis, Leonidas Stefanis, Athina Maria Simitsi, Enza Maria Valente, Simona Petrucci, Stefano Duga, Letizia Straniero, Anna Zecchinelli, Gianni Pezzoli, Laura Brighina, Carlo Ferrarese, Grazia Annesi, Andrea Quattrone, Monica Gagliardi, Hirotaka Matsuo, Yusuke Kawamura, Nobutaka Hattori, Kenya Nishioka, Sun Ju Chung, Yun Joong Kim, Carl E Clarke

Research output: Contribution to journalArticlepeer-review


Background: Previous prospective studies highlighted dairy intake as a risk factor for Parkinson's disease (PD), particularly in men. It is unclear whether this association is causal or explained by reverse causation or confounding.

Objective: The aim is to examine the association between genetically predicted dairy intake and PD using two-sample Mendelian randomization (MR).

Methods: We genotyped a well-established instrumental variable for dairy intake located in the lactase gene (rs4988235) within the Courage-PD consortium (23 studies; 9823 patients and 8376 controls of European ancestry).

Results: Based on a dominant model, there was an association between genetic predisposition toward higher dairy intake and PD (odds ratio [OR] per one serving per day = 1.70, 95% confidence interval = 1.12–2.60, P = 0.013) that was restricted to men (OR = 2.50 [1.37–4.56], P = 0.003; P-difference with women = 0.029).

Conclusions: Using MR, our findings provide further support for a causal relationship between dairy intake and higher PD risk, not biased by confounding or reverse causation. Further studies are needed to elucidate the underlying mechanisms.
Original languageEnglish
Pages (from-to)857-864
JournalMovement Disorders
Issue number4
Early online date8 Jan 2022
Publication statusE-pub ahead of print - 8 Jan 2022


  • dairy intake; Parkinson's disease; Mendelian randomization

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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