Cut-off value of testes volume in young adults and correlation among testes volume, body mass index, hormonal level, and seminal profiles.

OBJECTIVES

To set a population-based cut-off value of normal adult and to determine correlations of testicular volume with body mass index (BMI), seminal profiles, and hormone levels. Testicular volume is an index of male fertility but cut-off values of normal adult has not been reported.

METHODS

During 54 months from January 2004, 1139 normal young men, 19-27 years old in military service were enrolled. Testicular volumes were measured by ultrasonometry. Height, body weight, and BMI were measured and semen analysis and hormone assay (follicle-stimulating hormone [FSH], luteinizing hormone [LH], and testosterone) were performed.

RESULTS

The mean age was 23.52+/-2.74. The mean testicular volume was 18.37+/-3.62 cm3 in left, and 18.13+/-3.85 cm3 in right. The mean body weight was 67.4+/-7.91 kg, the mean height was 176.2+/-6.64 cm, and mean BMI was 22.49+/-2.02 kg/m2. Testicular volumes had significant but weak correlations with height, body weight, and BMI. The semen analyses showed a mean pH of 7.63+/-0.74, volume of 2.49+/-1.12 mL, count of 68.63+/-13.62x10(6), motility of 69.93%+/-10.28%, and morphology of 68.62%+/-7.48%. Sperm counts and motility had positive correlations with testicular volume. The mean hormonal levels of FSH, LH, and testosterone were 7.31+/-2.42 mIU/mL, 7.81+/-2.49 mIU/mL, and 6.23+/-1.69 ng/mL, respectively. Testicular volume was negatively correlated with FSH and LH and positively with testosterone.

CONCLUSIONS

In this population-based study, we conclude that the cut-off testicular volume in normal young adults is around 18 mL and that testicular volume is positively correlated with height, body weight, BMI, semen profile, and testosterone, and negatively correlated with FSH and LH.