Are serum levels of vitamin D associated with semen quality? Results from a cross-sectional study in young healthy men.
OBJECTIVE
To examine the association between low serum vitamin D concentration and estimates of male reproductive function.


METHODS
Cross-sectional study.


METHODS
University hospital.


METHODS
From a Danish pregnancy cohort established in 1984-1987, 347 sons were selected for a study conducted in 2005-2006.


METHODS
Semen parameters and reproductive hormones were related to vitamin D concentrations in 307 men.


METHODS
Semen characteristics and reproductive hormones.


RESULTS
A high vitamin D level was unexpectedly associated with lower crude median total sperm count and percentage of normal morphology sperm and a high level of crude median sex hormone-binding globulin and FSH. After adjustment, the associations attenuated to nonsignificant associations, except for sex hormone-binding globulin. Additionally, adjusted free androgen index was lower at higher vitamin D levels, and men with high vitamin D had 11% (95% confidence interval, 1%-20%) lower free androgen index compared with men with low vitamin D.


CONCLUSIONS
These results do not indicate that low vitamin D is a risk factor for poor semen quality in a population of young healthy men, but we may not have enough men with low vitamin D levels to detect an effect. New studies should include a larger proportion of vitamin D-deficient men.
Department of Occupational Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Epidemiology, Institute of Public Health, University of Aarhus, Aarhus, Denmark.
Cecilia Høst
CH
Ramlau-Hansen
Ulla Kristine
UK
Moeller
Jens Peter
JP
Bonde
Jørn
J
Olsen
Ane Marie
AM
Thulstrup
D000328:Adult; D000728:Androgens / Q000097:blood; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D008297:Male; D009845:Oligospermia / Q000097:blood* / Q000453:epidemiology*; D011247:Pregnancy; D018873:Pregnancy Rate; D012307:Risk Factors; D012661:Semen / Q000166:cytology; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology*; D055815:Young Adult
D000728:Androgens; D012738:Sex Hormone-Binding Globulin; D014807:Vitamin D; D005640:Follicle Stimulating Hormone; C104450:25-hydroxyvitamin D