Urinary phthalate metabolites and biomarkers of reproductive function in young men.
BACKGROUND
High exposure to phthalates, which are ubiquitous contaminants, has been shown in animal studies to produce detrimental effects on male reproductive functions. A recent study in humans reported dose-response relations between low phthalate levels in urine and human semen parameters, which raises the question whether humans are more sensitive to phthalate exposure than animals.


METHODS
Urine, serum, and semen samples were collected from 234 young Swedish men at the time of their medical conscript examination. Semen volume, sperm concentration, and motility were measured, together with sperm chromatin integrity (sperm chromatin structure assay) and biochemical markers of epididymal and prostatic function. We analyzed reproductive hormones in serum, and mono ethyl phthalate (MEP), mono ethylhexyl phthaltale (MEHP), mono benzyl phthalate (MBzP), mono butyl phthalate (MBP), and phthalic acid in urine.


RESULTS
For MBP, MBzP, and MEHP, no clear pattern of associations were observed with any of the reproductive biomarkers. Subjects within the highest quartile for MEP had fewer motile sperm (mean difference = 8.8%; 95% confidence interval = 0.8-17), more immotile sperms (8.9%; 0.3-18), and lower luteinizing hormone values (0.7 IU/L; 0.1-1.2), but there was no suggestion of harmful effects for most other endpoints. Phthalic acid actually was associated with improved function, as measured by several markers.


CONCLUSIONS
The observed weak associations between 1 phthalate biomarker and impairment of a few aspects of reproductive function biomarkers were not consistent with results from a recent U.S. study. It is not yet possible to conclude whether phthalate exposure may reflect a hazard for human male reproduction.
Jönsson
Bo A G
BA
Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, Lund University Hospital, Lund, Sweden. Bo_Jonsson@ymed.lu.se
Richthoff
Jonas
J
Rylander
Lars
L
Giwercman
Aleksander
A
Hagmar
Lars
L
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D004781:Environmental Exposure / Q000009:adverse effects*; D042341:Gonadal Hormones / Q000097:blood; D006801:Humans; D016014:Linear Models; D008297:Male; D008889:Military Personnel; D010795:Phthalic Acids / Q000097:blood / Q000633:toxicity* / Q000652:urine*; D012098:Reproduction / Q000187:drug effects*; D012661:Semen; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects*; D013548:Sweden
D015415:Biomarkers; D042341:Gonadal Hormones; D010795:Phthalic Acids; C032279:phthalic acid