Sociodemographic, lifestyle and medical factors associated with calculated free testosterone concentrations in men: individual participant data meta-analyses (IPDMA)

MD Nick Narinx; Marriott PhD Ross J; PhD Kevin Murray; MD Shalender Bhasin; MD,MHS Adrian S Dobs; PhD Leon Flicker MBBS,; MD Graeme J Hankey MBBS,; Robin Haring PhD; Alvin M Matsumoto MD; MD Eric S Orwoll; MD Gary A Wittert MBBCh,; MD Frederick C W Wu MBChB,; PhD Leen Antonio MD,; PhD Dirk Vanderschueren MD,; PhD Bu B Yeap MBBS,

doi:10.1530/endoabs.106.011

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Endocrine Abstracts (2024) 106 011 | DOI: 10.1530/endoabs.106.011

BES2024 BES 2024 CLINICAL STUDIES (17 abstracts)

Sociodemographic, lifestyle and medical factors associated with calculated free testosterone concentrations in men: individual participant data meta-analyses (IPDMA)

Nick Narinx MD¹, Ross J Marriott PhD², Kevin Murray PhD², Shalender Bhasin MD³, Adrian S Dobs MD,MHS⁴, Leon Flicker MBBS, PhD^5,6, Graeme J Hankey MBBS, MD^5,7, Robin Haring PhD^8,9, Alvin M Matsumoto MD^10,11, Eric S Orwoll MD¹², Gary A Wittert MBBCh, MD¹³, Frederick C W Wu MBChB, MD¹⁴, Leen Antonio MD, PhD¹, Dirk Vanderschueren MD, PhD^1* & Bu B Yeap MBBS, PhD^11,15*

Author affiliations

* joint senior authors
¹Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium. ²School of Population and Global Health, University of Western Australia, Perth, Australia. ³Brigham and Women’s Hospital, Harvard Medical School, Boston, USA. ^4.School of Medicine, Division of Endocrinology, Diabetes and Metabolism, Johns Hopkins University, Baltimore, Maryland, USA.⁵Medical School, University of Western Australia, Perth, Australia. ⁶Western Australian Centre for Healthy Ageing, University of Western Australia, Perth, Australia. ⁷Perron Institute for Neurological and Translational Science, Perth, Australia. ⁸School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. ⁹European University of Applied Sciences, Faculty of Applied Public Health, Rostock, Germany. ¹⁰Department of Medicine, University of Washington School of Medicine, Seattle, USA. ¹¹Geriatric Research, Education and Clinical Center, VA Puget Sound Health Care System, Seattle, USA. ¹²Oregon Health and Science University, Portland, USA. ¹³Freemasons Centre for Men’s Health and Wellbeing, School of Medicine, University of Adelaide, Adelaide, Australia. ¹⁴Division of Endocrinology, Diabetes & Gastroenterology, School of Medical Sciences, University of Manchester, Manchester, UK. ¹⁵Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth, Australia

Objective: Sociodemographic, lifestyle and medical variables influence total testosterone (T) and sex hormonebinding globulin (SHBG) concentrations. The relationship between these factors and “free” T remains unclear. We examined 21 sociodemographic, lifestyle and medical predictors influencing calculated free T (cFT) in community-dwelling men across ages.

Design: Cross-sectional analysis in 20,631 participants in the Androgens in Men Study.

Methods: Individual participant data (IPD) were provided by nine population cohorts. Total T was determined using mass spectrometry, SHBG using immunoassays and cFT using the Vermeulen formula. Associations were analysed using two-stage random effects IPD meta-analyses. Covariates including age, body mass index (BMI), marital status, and education were incorporated across all models. Additionally alcohol consumption, physical activity, and smoking were accounted for in models for lifestyle and medical variables.

Results: Cohort median ages ranged from 40 to 76 years and median cFT concentrations from 174.3 to 422.8 pmol/l. In men aged 17 - 99 years, there was a linear inverse association of cFT with age (-57.2 pmol/l [95% confidence interval, -69.4, -44.9] per 1-SD increase in age). cFT increased with increasing baseline BMI among men with BMI < 23.6 kg/m², but decreased among men with BMI > 23.6 kg/m² (-24.7 pmollL [95% CI, -29.1, -20.3] per 1-SD increase in the 25.4 - 29.6 kg/m² BMI range). cFT was lower in younger men, who were married or in a de facto relationship (-18.4 pmollL [95% CI, -27.6, -9.3]), and in men who; formerly smoked (-5.7 pmol/l [95% CI, -8.9, -2.6]); were in poor general health (-14.0 pmol/l [95% CI, 20.1,-7.8]); had diabetes (-19.6 pmol/l [95% CI, -23.0, -16.3]), cardiovascular disease (-5.8 pmol/l [95% CI, -8.3,-3.2]) or cancer (-19.2 pmol/l [95% CI, -24.4, -14.1]).

Conclusion: cFT was most prominently associated with age and BMI. The linear, inverse association with age, nonlinear association with BMI, and presence of diabetes, cancer and socio-demographic factors should be considered when interpreting cFT values.