AUTHOR=Xu Jiahao , Fan Peidong , Yang Jiacheng , Yin Mingjuan , Wu Jun , Chen Chao , Ni Jindong 

TITLE=Causal relationship between circulating insulin-like growth factor-1 and Parkinson’s disease: a two-sample Mendelian randomization study

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=16

YEAR=2024

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2024.1333289

DOI=10.3389/fnagi.2024.1333289

ISSN=1663-4365

ABSTRACT=<sec id="sec1"><title>Background</title><p>Linear associations between circulating insulin-like growth factor-1 (IGF-1) levels and Parkinson’s disease (PD) have been evidenced in observational studies. Yet, the causal relationship between IGF-1 levels and PD remains obscure. We conducted Mendelian randomization to examine the correlation between genetically predicted IGF-1 levels and PD.</p></sec><sec id="sec2"><title>Methods</title><p>By reviewing genome-wide association studies (GWAS) that are publicly accessible, we uncovered SNPs linked to both serum concentrations of IGF-1 and PD. A two-sample Mendelian randomization (MR) analysis was carried out to evaluate the individual effect of IGF-1 on PD.</p></sec><sec id="sec3"><title>Results</title><p>In a primary causal effects model in MR analysis, employing the inverse-variance weighted (IVW) method, IGF-1 levels exhibited a notable association with the risk of PD (OR, 1.020, 95% CI, 1.003–1.038, <italic>p</italic> = 0.0215). Multiple evaluations revealed that horizontal pleiotropy was improbable to distort the main results (MR-Egger: P PD intercept =0.719), and no bias was detected by leave-one-out analysis.</p></sec><sec id="sec4"><title>Conclusion</title><p>This study unearthed evidence indicating that heightened IGF-1 levels might be causally correlated with an increased risk of PD.</p></sec>