Body mass index in relation to semen quality and reproductive hormones among 1,558 Danish men.
OBJECTIVE
To examine the relationship between body mass index (BMI) and semen quality among young men from the general population.


METHODS
Cross-sectional study.


METHODS
Danish young men were approached when they attended a compulsory physical examination to determine their fitness for military service.


METHODS
From 1996-1998, 1,558 (19%) young men (mean age 19 years) volunteered.


METHODS
Semen volume (in milliliters), sperm concentration (in million per milliliter), percentage of motile spermatozoa, percentage of spermatozoa with normal morphology, total sperm count (in million), and testis size (in milliliters). In addition, serum reproductive hormones were measured.


RESULTS
Serum T, sex hormone-binding globulin (SHBG), and inhibin B all decreased with increasing BMI, whereas free androgen index and E(2) increased with increasing BMI. Serum FSH was higher among slim men. After control for confounders, men with a BMI <20 kg/m(2) had a reduction in sperm concentration and total sperm count of 28.1% (95% confidence interval [CI] 8.3%-47.9%) and 36.4% (95% CI 14.6%-58.3%), respectively, and men with a BMI >25 kg/m(2) had a reduction in sperm concentration and total sperm count of 21.6% (95% CI 4.0%-39.4%) and 23.9% (95% CI 4.7%-43.2%), respectively, compared to men with BMI between 20-25 kg/m(2). Percentages of normal spermatozoa were reduced, although not significantly, among men with high or low BMI. Semen volume and percentage of motile spermatozoa were not affected by BMI.


CONCLUSIONS
High or low BMI was associated with reduced semen quality. It remains to be seen whether the increasing occurrence of obesity in the Western world may contribute to an epidemic of poor semen quality registered in some of the same countries. If so, some cases of subfertility may be preventable.
University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark. tkjensen@health.sdu.dk
Tina Kold
TK
Jensen
Anne-Maria
AM
Andersson
Niels
N
Jørgensen
Anne-Grethe
AG
Andersen
Elisabeth
E
Carlsen
Jørgen Holm
JH
Petersen
Niels E
NE
Skakkebaek
D000293:Adolescent; D000428:Alcohol Drinking; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D003718:Denmark; D004958:Estradiol / Q000097:blood; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D007265:Inhibins / Q000097:blood; D016014:Linear Models; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D012661:Semen / Q000502:physiology*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D012907:Smoking; D013076:Sperm Count; D013081:Sperm Motility / Q000502:physiology; D013737:Testis / Q000502:physiology*; D013739:Testosterone / Q000097:blood; D014505:Urban Population
D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; C422364:inhibin B; D013739:Testosterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone