Anthropometric, functional and lifestyle-related factors associated with testosterone levels among middle-aged men in Uzbekistan: protocol for a population-based cross-sectional study.

introductionTestosterone deficiency in middle-aged men is associated with a wide range of adverse health outcomes, including metabolic disorders, reduced physical performance, sarcopenia, impaired sexual function, psychological distress and decreased quality of life. Despite its growing clinical and public health importance, early identification of men at increased risk remains challenging. Current diagnostic approaches rely primarily on laboratory assessment of testosterone levels, which may not adequately reflect symptom burden and are often inaccessible in resource-limited settings. There is therefore a need for comprehensive and practical approaches that integrate anthropometric, functional and lifestyle-related factors associated with serum total testosterone levels. METHODS AND ANALYSIS: This population-based analytical cross-sectional study will be conducted among middle-aged men aged 35-59 years residing in the Andijan region of Uzbekistan. Approximately 600 participants will be recruited through community-based screening programmes, primary healthcare institutions, workplace outreach and public announcements. Data collection will include anthropometric measurements, assessment of muscle strength and physical performance, lifestyle characteristics, dietary habits, sleep quality, symptoms suggestive of testosterone deficiency, lower urinary tract symptoms, muscle function and laboratory evaluation of serum total testosterone concentrations. Standardised questionnaires and validated clinical assessment tools will be used. The primary outcome is serum total testosterone concentration. Secondary outcomes include identification of anthropometric, functional and lifestyle-related factors associated with serum total testosterone levels and development of a multivariable predictive model for the early identification of testosterone deficiency. Statistical analyses will include correlation analyses, multivariable linear and logistic regression models and receiver operating characteristic curve analysis to evaluate model performance. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of the Ministry of Health of the Republic of Uzbekistan (Approval No. 4/26-2380, 13 May 2026) and registered at ClinicalTrials.gov (NCT07476222). Written informed consent will be obtained from all participants before enrolment. Study findings will be disseminated through peer-reviewed publications, scientific conferences and academic networks. The results are expected to contribute to the development of accessible screening strategies for the early identification of testosterone deficiency among middle-aged men. TRIAL REGISTRATION NUMBER: NCT07476222.