Age-Specific Normative Data on Testicular Volume and Serum Testosterone Levels in Apparently Healthy Boys from...

To establish age-specific normative reference values for mean testicular volume and serum testosterone levels in apparently healthy north Indian boys aged 5-20 years (with centile curves extended to 4-20 years), and to evaluate their associations with anthropometric, biochemical, and pubertal indicators.

In this observational cross sectional study, apparently healthy boys aged 5-20 years were recruited from schools and community centers in northern India (2019-2023). Testicular volume was measured using Prader's orchidometer, and serum testosterone via chemiluminescence immunoassay. Secondary measures included anthropometry, biochemical markers [luteinizing hormone (LH), follicle-stimulating hormone (FSH), vitamin D, albumin], and body composition by bioelectrical impedance analysis (BIA).

In a total of 1,022 boys, both testicular volume and serum testosterone levels exhibited significant age-related increases (most marked progression between 11 and 15 years. After adjusting for age, higher testicular volume was significantly associated with increased BMI, LH, FSH, muscle mass, and bone mass (P < 0.001), while no significant association was found with vitamin D or albumin levels. Age-specific centile curves for both parameters were generated using the LMS method.

This large-scale study provides age-specific normative reference values for testicular volume and serum testosterone in apparently healthy boys from a single center in northern India. These values are clinically valuable for assessing pubertal progression and managing growth and endocrine disorders in Indian populations.