Follicle-Stimulating Hormone and Diabetes in Postmenopausal Women: A Systematic Review and Meta-Analysis

Abstract

Background Today, co-occurrence of hormonal changes during menopause and the risk of cardio-metabolic disorders have been well studied. We aimed to explore the association of circulating levels of follicle-stimulating hormone (FSH) with diabetes (DM) among postmenopausal women. Method In this Systematic review and meta-analysis the search was performed on PubMed, Scopus, Web of sciences, Epistemonikos, and Cochrane library until the September 2023. Risk of bias was assessed by Newcastle-Ottawa Quality Assessment Scale. Pooled estimates of mean differences in FSH levels among diabetic postmenopausal women compared to those without diabetes were performed. Also, the correlation between FSH and fasting blood glucose (FBG)/Insulin/Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) as well as the pooled effect sizes with their 95% confidence intervals (CIs) for risk of DM were calculated. Results In this study, 14 articles, including 7,878 postmenopausal women, met eligibility criteria and were further analyzed. Most of the included studies had a low/moderate risk of bias. Women with DM had significantly lower FSH levels than those without DM (standardized mean difference [95% CI] -0.751, 95% CI-1.129 to -0.372, I2 = 82.46%, n = 1416). The pooled effect size (ES) for diabetes was 0.861 (95% CI: 0.740-1.001; I2 = 80.11%). The pooled risk estimate for DM based on the categorical FSH levels (high versus low) was (HR = 0.550; 95% CI, 0.356 to 0.850, I2 = 0). The significant inverse correlation was found between FSH levels and glycemic parameters [FBG (r= -0.285; 95%CI -0.441 to -0.113; n = 1229), HOMA-IR (r = -0.241; 95%CI -0.378 to -0.0924; n = 1229) and Insulin (r = -0.337; 95%CI -0.434 to -0.232; n = 959)]. There were no statistically significant differences between estradiol levels among diabetic and non-diabetic groups; however the SMD for luteinizing hormone was similar to that reported for FSH. Conclusion The available data indicated an indirect association between FSH levels and glucose disturbances among postmenopausal women; notwithstanding heterogeneity among included studies, and the complexity of various influential factors needs to be considered. Further efforts should be made to clarify the underlying mechanisms.