Annals of Internal MedicineFactors Associated with Circulating Sex Hormones in Men

Unveiling the Factors That Influence Male Testosterone Levels

Understanding the factors that influence testosterone levels in men is crucial for accurate diagnosis and treatment. A recent meta-analysis delves into the various sociodemographic, lifestyle, and health factors that affect testosterone and other sex hormone concentrations in men.

HCN Medical Memo
This study underscores the need for a nuanced approach to interpreting testosterone levels. Particularly for men over 70, obesity, diabetes, and cancer should be considered as factors that may influence testicular function. Accurate diagnosis requires accounting for these variables.

Study Design:

• Participants: Community-dwelling men with total testosterone measured using mass spectrometry.
• Data Sources: Systematic literature searches up to July 2019.
• Data Extraction: Individual participant data from 9 studies (n = 21,074) and aggregate data from 2 studies (n = 4,075).
• Limitations: Cross-sectional analysis, heterogeneity between studies, timing of blood sampling, and imputation for missing data.

This study demonstrated that testosterone levels show negligible change among men aged 17 to 70 years but decrease significantly for men older than 70.

Key Findings:

• Testosterone is inversely associated with BMI.
• Lower testosterone concentrations were observed in men who were married, undertook minimal physical activity, were former smokers, or had hypertension, cardiovascular disease, cancer, or diabetes.
• SHBG is directly associated with age and inversely associated with BMI.
• LH is directly associated with age in men older than 70 years.

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