The risk of Parkinson's disease in diabetic people: an updated systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational (cohort and case-control) studies
PubMed 37982931 · doi:10.1007/s13760-023-02424-6
What was done
Authors conducted a systematic review and meta-analysis of cohort and case-control studies searched across PubMed/Medline, Web of Science, Scopus, and EMBASE through January 2023. The analysis evaluated the relationship between diabetes mellitus (DM) and the risk of developing Parkinson's disease (PD), with subgroup analyses by geographic continent, age, DM and PD diagnostic criteria, PD duration, and effect size metric.
What was found
The meta-analysis included 25 studies covering 39,209,316 total participants. The pooled relative risk for the association between DM and PD was 1.22 (95% CI 1.08–1.37). Subgroup analyses showed higher relative risk among Asian populations, younger individuals, and those with longer PD duration.
Why it matters
This updated large-scale meta-analysis reinforces observational evidence that diabetes is modestly associated with an increased subsequent risk of Parkinson's disease, supporting shared metabolic or neurodegenerative pathways.
Limits
The analysis relies entirely on observational studies (cohort and case-control designs) susceptible to unmeasured confounding and reverse causation. The abstract does not report heterogeneity statistics (such as I²), publication bias assessments, DM type stratification (type 1 vs. type 2), or individual confounder adjustments such as antidiabetic medications or smoking.
Cited by
- contradicts Having type 2 diabetes increases the risk of developing Parkinson's disease by 85%.