Is education a risk factor for Parkinso's disease?: A systematic review and meta-analysis

Parkinsons disease (PD) has shown a twofold increase in global prevalence over the past 25 years, making research into its causes pivotal. Curiously, higher educational attainment has often been linked to a higher risk of PD. Yet, to our knowledge, these findings have not been validated in a systematic literature review and meta-analysis. Thus, we systematically searched PubMed, Psychinfo, Web of Science and Embase and performed citation and similar article searches. We included reports of non-interventional quantitative studies that assessed the association between education and the risk of PD. Furthermore, we included studies that evaluated the association between educational level and symptom burden. For the primary outcome, we performed a random-effects meta-analysis. The secondary outcome was synthesized qualitatively. We conducted multiple a priori subgroup analyses. Risk of bias was assessed using the QUIPS tool. This study was registered on PROSPERO (ID: CRD420250651033). Of 23,648 identified reports, 36 papers met inclusion criteria. Most of these had moderate or high overall risk of bias. Meta-analytic findings yielded no significant association between education and risk of PD, with a pooled odds ratio of 1.09 (k = 24; 95% CI: 0.92 - 1.28). Sensitivity analyses yielded similar results. Subgroup analyses did not explain observed heterogeneity. There was no evidence of small study effects or p-hacking. Education appeared to be associated with reduced PD symptom severity but the number and quality of studies was limited. Education is unlikely to be an independent risk factor for PD. Study heterogeneity and methodological limitations preclude firm conclusions, though.