SHBG levels in primary infertile men: a critical interpretation in clinical practice

• Main Authors: Luca Boeri, Paolo Capogrosso, Walter Cazzaniga, Edoardo Pozzi, Luigi Candela, Federico Belladelli, Davide Oreggia, Eugenio Ventimiglia, Nicolò Schifano, Giuseppe Fallara, Marina Pontillo, Costantino Abbate, Emanuele Montanari, Francesco Montorsi, Andrea Salonia
• Format: Article
• Language: English
• Published: Bioscientifica 2020-07-01
• Series: Endocrine Connections
• Subjects: infertility; testosterone; hypogonadism; sex hormone-binding globulin; obesity
• Online Access: https://ec.bioscientifica.com/view/journals/ec/9/7/EC-20-0183.xml

Objective: We aimed to test the association between age, BMI and sex-horm one–binding globulin (SHBG) in a homogenous cohort of white-European men presenting for primary couple’s infertility. Design: Retrospective study. Methods: Data from 1547 infertile men were analysed. Health-significant comorbidities were scored with the Charlson comorbidity index (CCI). Fasting serum hormones were measured in every patient. Age was considered according to quartile groups (<33, 33-41, >41 years) and BMI as normal weight (18.5–24.9 kg/m 2), overweight (25.0–29.9 kg/m2) and obesity (>30 kg/m2). Descriptive statistics and linear regression analysis tested the associations between age, BMI and SHBG. Results: Median SHBG levels increased across quartiles of age and decre ased along with BMI increases (all P < 0.001). For each year increase in age, SHBG increased 0.32 nmol/L; conversely, for each unit increase in BMI, SHBG de creased by 1.1 nmol/L (all P < 0.001). SHBG levels decline with increasing BMI was greater than SHBG progressive increase with age. Overall, BMI explained 3.0 times more of the variability in SHBG than did ageing. At multivariate linear model, age and BMI were the most significant factors influencing SHBG concentration (all P < 0.001), after accounting for CCI, albumin levels and smoking status. Conclusions: We found a wide distribution of SHBG concentrations across age and BMI values in primary infertile men. The association between BMI an d lowered SHBG levels seems to be greater than the association of ageing with increased SHBG.