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

Testosterone plays an important role in maintaining male reproductive health, body composition, muscle strength and metabolic homeostasis. Reduced testosterone levels in middle-aged men have been associated with an increased risk of metabolic syndrome, obesity, type 2 diabetes mellitus, cardiovascular diseases, reduced physical performance and impaired quality of life. Despite increasing recognition of testosterone deficiency as an important public health issue, many cases remain unrecognised because of nonspecific clinical manifestations.

Previous studies have demonstrated that obesity, physical inactivity, poor sleep quality, unhealthy dietary patterns and other lifestyle-related factors may influence serum testosterone levels. However, the combined associations of anthropometric characteristics, functional status and lifestyle-related factors with serum testosterone levels remain insufficiently investigated, particularly in population-based studies involving middle-aged men.

The present study is designed as a population-based cross-sectional observational study aimed at investigating 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 height, body weight, body mass index, waist circumference, hip circumference, waist-to-hip ratio and waist-to-height ratio. Functional performance will be assessed using hand-grip strength, the five-times chair-stand test and the 4-m walk test.

Lifestyle-related characteristics will be evaluated using validated questionnaires assessing physical activity, sleep quality, dietary habits, lower urinary tract symptoms, symptoms suggestive of testosterone deficiency and muscle function. Additional information regarding smoking status, alcohol consumption, occupational characteristics, medical history and comorbidities will also be collected.

Venous blood samples will be collected between 08:00 and 10:00 hours following an overnight fast. Serum total testosterone concentrations will be measured using standardised laboratory procedures.

Statistical analyses will include correlation analyses, multivariable linear and logistic regression models, and receiver operating characteristic (ROC) curve analysis to identify factors associated with serum total testosterone levels and decreased total testosterone levels. Based on the study findings, a multivariable predictive model will be developed for the early identification of men at increased risk of testosterone deficiency.

The findings of this study are expected to improve understanding of anthropometric, functional and lifestyle-related factors associated with serum total testosterone levels and to support the development of accessible risk assessment strategies for the early identification of testosterone deficiency in middle-aged men.

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