Anthropometric, Functional and Lifestyle Factors Associated With Testosterone Levels in Middle-Aged Men

Decreased testosterone levels in middle-aged men are associated with multiple metabolic, functional and psychosocial consequences. Early identification of modifiable factors associated with reduced testosterone levels may facilitate the early identification of men at increased risk of testosterone deficiency and support preventive healthcare strategies. This population-based cross-sectional observational study aims to investigate anthropometric, functional and lifestyle-related factors associated with serum total testosterone levels in middle-aged men. Approximately 600 men aged 35-59 years residing in the Andijan region of Uzbekistan will be recruited. Participants will undergo comprehensive assessment including anthropometric measurements, functional performance tests, standardised questionnaires and laboratory determination of serum total testosterone concentrations. Anthropometric variables will include body mass index, waist circumference, hip circumference, waist-to-hip ratio and waist-to-height ratio. Functional status will be assessed using hand-grip strength, the five-times chair-stand test and the 4-m walk test. Lifestyle-related factors will be assessed using standardised and study-specific questionnaires. Physical activity will be assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), while dietary habits, sleep characteristics, smoking status, alcohol consumption and psychosocial characteristics will be assessed using a structured study questionnaire. The study aims to identify factors associated with serum total testosterone levels and to develop a predictive model for the early identification of men at increased risk of testosterone deficiency.

Inclusion Criteria: * Men aged 35-59 years * Permanent residence in the Andijan region of Uzbekistan * Ability and willingness to provide written informed consent * Willingness to undergo clinical, anthropometric, functional and laboratory assessments Exclusion Criteria: * Previously diagnosed hypogonadism requiring testosterone replacement therapy * Current use of testosterone preparations or other medications known to substantially affect androgen status * Severe cardiovascular, hepatic or renal disease in the stage of decompensation * Clinically significant urological pathology * Severe psychiatric illness or cognitive impairment limiting study participation * Acute infectious or inflammatory conditions at the time of assessment