• case–control analysis;
  • epidemiology;
  • non-steroidal anti-inflammatory drugs;
  • Parkinson disease

Background:  Previous epidemiologic studies have produced inconsistent findings regarding the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of Parkinson disease (PD).

Methods:  We conducted a case–control analysis using the General Practice Research Database. Cases (≥40 years) had a new diagnosis of PD between 1994 and 2009. We matched four controls to each PD case on age, sex, general practice, and index date. Use of NSAIDs, aspirin, and acetaminophen was stratified by exposure timing and duration for both cases and controls. We calculated odds ratios (OR) using conditional logistic regression. For additional analyses, the index date was brought backward 1, 2, and 3 years, respectively.

Results:  We identified 4026 cases with an incident idiopathic PD diagnosis and 15 969 matched controls. Compared with patients without any previous prescription for NSAIDs, those with prior use had no increased risk of a PD diagnosis (OR 1.07, 95% CI 0.99–1.16). Long-term use (≥15 prescriptions) was associated with a slightly lower PD risk (adjusted OR 0.94, 95% CI 0.83–1.07). The relative PD risks of the use of aspirin or acetaminophen were not materially higher (PD risk of long-term use: adjusted ORs 1.16, 95% CI 1.03–1.30 and 1.15, 95% CI 1.02–1.30, respectively) compared with those for non-users. The risk estimate diminished toward the null in subsequent analyses with shifted index dates.

Conclusion:  In this large observational study with data from the UK primary care, the long-term use of NSAIDs, aspirin, or acetaminophen was not associated with a substantially altered risk of developing PD.