Visceral and subcutaneous adipose tissue assessed by magnetic resonance imaging in relation to circulating androgens, sex hormone-binding globulin, and luteinizing hormone in young men.
BACKGROUND
No large studies of young men have examined circulating sex hormones in relation to visceral and sc adipose tissues.


OBJECTIVE
The aim of this study was to investigate the role of visceral adipose tissue and sc adipose tissue on circulating sex hormones and the impact of obesity on sex hormone reference intervals.


METHODS
Population-based study of 783 Danish 20- to 29-yr-old men was performed using dual-energy x-ray absorptiometry in all men and magnetic resonance imaging in 406 men.


METHODS
Total, bioavailable, and free testosterone, dihydrotestosterone (DHT), total and bioavailable estradiol, SHBG, and LH were measured.


RESULTS
In multiple regressions, visceral adipose tissue was an independent, inverse correlate of bioavailable and free testosterone. Subcutaneous adipose tissue correlated negatively with SHBG and positively with bioavailable estradiol adjusted for total testosterone. Both visceral adipose tissue and sc adipose tissue correlated inversely with total testosterone and DHT. Adjusting for SHBG, only visceral adipose tissue remained significantly correlated. Low total testosterone in viscerally obese men was not accompanied by increased LH. The androgen reference intervals were significantly displaced toward lower limits in obese vs. nonobese men (total testosterone: 8.5-29.3 vs. 12.5-37.6 nmol/liter; bioavailable testosterone: 6.1-16.9 vs. 7.6-20.7 nmol/liter; free testosterone: 0.23-0.67 vs. 0.29-0.78 nmol/liter; and DHT: 0.63-2.5 vs. 0.85-3.2 nmol/liter), whereas total estradiol (36.5-166 pmol/liter) and bioavailable estradiol (23.4-120 pmol/liter) reference intervals were not. In obese men, 22.9% had total testosterone less than 12.5 nmol/liter.


CONCLUSIONS
Visceral adipose tissues correlate independently with bioavailable and free testosterone in young men. The inverse relationship between total testosterone and sc adipose tissue seems to be accounted for by variations in SHBG. The reference intervals for total testosterone, bioavailable testosterone, free testosterone, and DHT are displaced toward lower limits in obese men.
Nielsen
Torben Leo
TL
Department of Endocrinology, Odense University Hospital, 5250 Odense SV, Denmark. Torben@dsa-net.dk
Hagen
Claus
C
Wraae
Kristian
K
Brixen
Kim
K
Petersen
Per Hyltoft
PH
Haug
Egil
E
Larsen
Rasmus
R
Andersen
Marianne
M
D015502:Absorptiometry, Photon; D000328:Adult; D013196:Dihydrotestosterone / Q000097:blood; D004958:Estradiol / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D050152:Intra-Abdominal Fat / Q000166:cytology / Q000000981:diagnostic imaging / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D008279:Magnetic Resonance Imaging; D008297:Male; D009765:Obesity / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D012042:Registries; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D050151:Subcutaneous Fat / Q000166:cytology / Q000000981:diagnostic imaging / Q000378:metabolism*; D013739:Testosterone / Q000097:blood
D006728:Hormones; D012738:Sex Hormone-Binding Globulin; D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone