Lower Lymphocyte Count Linked With Increased Risk of Parkinson's Disease

Sarfaroj Khan 


February 08, 2021


  • Lower lymphocyte count was associated with an increased risk of subsequent diagnosis of Parkinson’s disease (PD).

  • Mendelian randomisation (MR) analysis suggested that this association may be causal.

Why this matters

  • Findings suggest that lower lymphocyte count, although lacking specificity as a biomarker in isolation, may enhance efforts to identify patients who are at the earliest stages of PD.

Study design

  • Study of 465 incident PD cases and 312,125 controls from the UK Biobank.

  • Association between incident PD and baseline differential leukocyte count and other blood markers of acute inflammation was evaluated.

  • Funding: None.

Key results

  • Each 1-standard deviation (SD) reduction in lymphocyte count was associated with an increased risk of incident PD (OR, 1.18; 95% CI, 1.07-1.32).

  • There was some evidence that the risk of PD was increased with each 1-SD reduction in:

    • eosinophil count (OR, 1.16; 95% CI, 1.04-1.3);

    • monocyte count (OR, 1.12; 95% CI, 1.01-1.26); and

    • C-reactive protein (OR, 1.13; 95% CI, 1.00-1.29).

  • Each 1-SD reduction in neutrophil count correlated with a lower risk of PD (OR, 0.91; 95% CI, 0.84-1.00).

  • The association between a lower lymphocyte count and an increased PD risk remained robust in sensitivity analyses.

  • Mendelian randomisation analysis suggested that each genetically estimated 1-SD reduction in lymphocyte count was associated with an increased risk of PD (OR, 1.09; 95% CI, 1.01-1.18; P=.02).


  • Risk of bias.


Jensen MP, Jacobs BM, Dobson R, Bandres-Ciga S, Blauwendraat C, Schrag A, Noyce AJ. Lower lymphocyte count is associated with increased risk of Parkinson's disease. Ann Neurol. 2021 Feb 2 [Epub ahead of print]. doi: 10.1002/ana.26034. PMID: 33527442 View abstract

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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