Premium
Comparison of testosterone fractions between F ramingham H eart S tudy participants and J apanese participants
Author(s) -
Taya Masaki,
Koh Eitetsu,
Izumi Kouji,
Iijima Masashi,
Maeda Yuji,
Matsushita Tomohiko,
Iwamoto Teruaki,
Namiki Mikio
Publication year - 2014
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/iju.12393
Subject(s) - medicine
Objectives To determine testosterone fractions in J apanese men and to compare these values with those of F ramingham H eart S tudy participants. Methods We enrolled 498 healthy J apanese men. Total testosterone was assayed by liquid chromatography tandem mass spectrometry, sex hormone‐binding globulin was assayed by immunoassay and free testosterone was calculated by a laboratory at the B oston M edical C enter. Analog‐based free testosterone and immunoassay‐based total testosterone were determined by immunoassay. We compared mass spectrometry assay‐based total testosterone and calculated free testosterone values in the J apanese participants with values in the A merican F ramingham H eart S tudy third generation cohort. Results The mean serum mass spectrometry assay‐based total testosterone, sex hormone‐binding globulin, and calculated free testosterone values were 439.4 ± 167 ng/dL, 65.34 ± 30.61 nmol/L, and 58.75 ± 20.0 pg/mL, respectively. The correlation coefficients with age for mass spectrometry assay‐based total testosterone, sex hormone‐binding globulin, and calculated free testosterone were 0.0010, 0.5041, and −0.496, respectively. There were no age‐related changes in mass spectrometry assay‐based total testosterone values in healthy men ( P = 0.981), whereas sex hormone‐binding globulin and calculated free testosterone levels showed similar age‐related changes ( P < 0.0001). Serum analog‐based free testosterone levels (8.24 ± 2.9 pg/mL) showed age‐related changes ( P < 0.0001) regardless of immunoassay‐based total testosterone levels ( P = 0.828). Serum immunoassay‐based total testosterone values (486.1 ± 162.5 ng/dL) correlated with serum mass spectrometry assay‐based total testosterone values ( r = 0.740, 95% confidence interval 0.6965–0.7781, P < 0.0001). Similarly, analog‐based free testosterone and calculated free testosterone values showed a highly significant correlation ( r = 0.706, 95% confidence interval 0.6587–0.7473, P < 0.0001). The analog‐based free testosterone values were approximately 10% of the calculated free testosterone values. Conclusions In contrast to the F ramingham H eart S tudy cohort, total testosterone values in J apanese men are not associated with advancing age; thus, they cannot be used to diagnose late‐onset hypogonadism in J apan. The analog‐based free testosterone value can be considered instead as a suitable biochemical determinant for diagnosing late‐onset hypogonadism syndrome.