Correlation of Sex Hormone Binding Globulin with Metabolic Syndrome in US Adults: Insights from National Health and Nutrition Examination Survey (NHANES) 2013–2016

Background Metabolic syndrome (MetS) poses a significant public health challenge worldwide, significantly impacting the health and quality of life of individuals. Increasing evidence suggests a strong correlation between MetS and sex hormone levels. The objective of this study is to explore the possible relationship between sex hormone binding globulin (SHBG) and Mets, aiming to furnish evidence that could inform the development of effective prevention strategies for Mets. Methods The data for this cross-sectional investigation were collected during the 2013–2016 cycle of the National Health and Nutrition Examination Survey (NHANES), from which 5,499 adults were sampled. The criteria established by the Adult Treatment Program III of the National Cholesterol Education Program were utilized to define MetS. SHBG were measured using a standardized technique. Multivariable-adjusted Logistic regression analysis, curve fitting, and threshold effects analysis were utilized to investigate the association between SHBG levels and Mets. Moreover, the stratified analyses and interaction tests of covariables were presented in the forest plot. Finally, sensitivity analysis was utilized to ensure the the robustness of the results. Results Among the participants, 1822 those had Mets. After adjusting for possible confounders, the SHBG level was associated with Mets (Odds ratio [OR], 0.984; 95% confidence interval [CI], 0.981–0.986; P < 0.01). The multivariable restricted cubic spline demonstrated a non-linear association between SHBG and Mets (P < 0.001). With two piecewise regression models, the adjusted OR of developing Mets was 0.964 (95% CI, 0.959–0.969; P < 0.001) among people with SHBG < 76.653nmol/L, but there was no correlation between SHBG and Mets in participants with SHBG ≥ 76.653nmol/L. The stability of the association between SHBG and MetS was confirmed through subgroup analysis and sensitivity analysis. Conclusions Our results suggest that reduced SHBG levels are associated with an increased prevalence of MetS in adults, particularly when SHBG levels are below 76.653 nmol/L. More investigation is required to comprehend the mechanisms underlying these results and to delve into their clinical implications.