Peripheral IGF-1 in bipolar disorder and major depressive disorder: a systematic review and meta-analysis

Background: In recent years, a number of studies have shown abnormal levels of peripheral insulin growth factor-1 (IGF-1) in patients with mood disorder, but the results are not uniform. Therefore, this paper focuses on such studies, conducts a systematic review and meta-analysis, and discusses the factors affecting peripheral IGF-1 in patients with mood disorder. Methods: Cochrane database, PubMed database, Embase database, CNKI database, Wanfang Database and Weipu database were searched by computer. The retrieval time was from June 2020 to search for a controlled study of the relationship between bipolar disorder (BD) or major depressive disorder and normal control peripheral IGF-1. Review Manager (version 5.3) software was used for meta-analysis. Results: A total of 14 articles in Chinese and English were included; 285 patients with BD and 503 patients with major depressive disorder. Meta-analysis showed that in comparison with the control group, IGF-1 levels in peripheral blood of patients with BD (MD = 67.66, 95% CI: 7.01-128.31, P=0.03) and major depressive disorder (MD = 8.01, 95% CI: 3.43-12.58, P=0.0006) were significantly increased. In the meta-analysis comparing the peripheral IGF-1 levels of patients before and after treatment, the results showed no significant change in the peripheral IGF-1 level before and after treatment (P=0.53). Conclusions: High peripheral IGF-1 level is a related factor of BD and major depressive disorder, although this needs to be confirmed by further large sample studies.