Associations between andrological measures, hormones and semen quality in fertile Australian men: inverse relationship between obesity and sperm output.
BACKGROUND
The World Health Organization developed a time to pregnancy (TTP) study (number of menstrual cycles taken to conceive) to determine whether the average TTP is increasing and semen quality decreasing with time. The present study describes clinical, semen and hormone characteristics obtained from male partners of pregnant women in Melbourne, Australia, and examines the associations between these characteristics.


METHODS
Male partners (n = 225) of pregnant women (16-32 weeks) who conceived naturally had physical examination, health and lifestyle questionnaires, semen and hormone (FSH, LH, sex hormone-binding globulin, testosterone and Inhibin B) analyses.


RESULTS
Previously known associations between semen, hormone and clinical variables were confirmed as significant: sperm numbers (concentration and total sperm count) correlated positively with Inhibin B and inversely with FSH and left varicocele, while total testicular volume correlated positively with sperm numbers and Inhibin B and inversely with FSH. However, only abstinence, total testicular volume, varicocele grade and obesity (BMI > 30 kg/m2) were independently significantly related to total sperm count. Compared with those with BMI < 30 (n = 188), obese subjects (n = 35) had significantly lower total sperm count (mean 324 versus 231 million, P = 0.013) and Inhibin B (187 versus 140 pg/ml, P < 0.001) but not FSH (3.4 versus 4.0 IU/l, P = 0.6).


CONCLUSIONS
Obese fertile men appear to have reduced testicular function. Whether this is cause or effect, i.e. adiposity impairing spermatogenesis or reduced testicular function promoting fat deposition, remains to be determined.
Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne IVF Reproductive Services, The Royal Women's Hospital, Melbourne, Australia. tstewart@unimelb.edu.au
T M
TM
Stewart
D Y
DY
Liu
C
C
Garrett
N
N
Jørgensen
E H
EH
Brown
H W G
HW
Baker
D000328:Adult; D000728:Androgens / Q000378:metabolism; D001315:Australia; D005260:Female; D005298:Fertility; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis; D006801:Humans; D007265:Inhibins / Q000096:biosynthesis; D007986:Luteinizing Hormone / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D011247:Pregnancy; D012661:Semen / Q000378:metabolism* / Q000502:physiology*; D012738:Sex Hormone-Binding Globulin / Q000096:biosynthesis; D013094:Spermatozoa / Q000502:physiology*; D013739:Testosterone / Q000096:biosynthesis
D000728:Androgens; D012738:Sex Hormone-Binding Globulin; C422364:inhibin B; D013739:Testosterone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone