Objective: To examine the link between antimicrobial use and Parkinson’s disease (PD) risk.
Background: Alterations of gut microbiota composition may contribute to the development of PD. The use of antimicrobial can impact gut microbiota, causing both short-term and long-term dysbiosis. Previous epidemiological studies have reported an increased risk of PD following exposure to antimicrobial agents, though findings vary considerably by antimicrobial class and remain inconsistent across studies.
Method: We conducted a nested case-control study in individuals aged ≥ 65 years living in Sweden between 2004 and 2020. Incident PD cases were identified between 2005 and 2022 from the National Patient Register and matched to up to ten controls on age and sex, with the index date defined as the date of PD diagnosis. Antimicrobial exposure was ascertained from the Drug Prescription Register, including antibiotics and antifungals for systemic use. Conditional logistic regression estimated odds ratios (ORs) adjusting for country of birth, education and chronic obstructive pulmonary disease as a proxy for heavy smoking. We defined antimicrobial exposure as the cumulative number of prescriptions and cumulative number of exposure days before the index date, categorized into quartiles.
Results: We identified 35,964 PD cases and 314,638 matched controls. Median length of follow-up was 7.6 years. Compared to non-users, individuals with a higher cumulative number of antibiotic prescriptions before index date were associated with increased risk of PD (Q1: OR 1.10, 95% CI 1.05-1.15; Q2: OR 1.14, 95% CI 1.08-1.20; Q3: OR 1.17, 95% CI 1.11-1.22; Q4: OR 1.22, 95% CI 1.16-1.27). We observed consistent estimates when using cumulative number of exposure days (Q1: 1.09, 95% CI: 1.04-1.14; Q2: 1.13, 95% CI: 1.08-1.18; Q3: 1.16, 95% CI: 1.11- 1.22; Q4: 1.20, 95% CI: 1.15-1.25).
Conclusion: In line with previous studies, our results suggest an association between exposure to antimicrobial agents and risk of PD.
To cite this abstract in AMA style:
S. Licaj, A. Ploner, M. Szilcz, J. Wastesson, S. Hägg, F. Fang, K. Wirdefeldt. Antimicrobial Use and Risk of Parkinson’s Disease: A Swedish National Case-control Study [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/antimicrobial-use-and-risk-of-parkinsons-disease-a-swedish-national-case-control-study/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/antimicrobial-use-and-risk-of-parkinsons-disease-a-swedish-national-case-control-study/