Impact of Di-2-Ethylhexyl Phthalate Metabolites on Male Reproductive Function: a Systematic Review of Human Evidence.
Level 4 - case-series / case-control
Systematic review comprised predominantly of cross-sectional observational studies (28 of 33 studies).
PubMed 29468520 · doi:10.1007/s40572-018-0174-3
What was done
The authors conducted a systematic review examining the relationship between di-2-ethylhexyl phthalate (DEHP) exposure and reproductive health outcomes in adult males. The review identified 33 eligible studies: 28 were cross-sectional designs. Across these papers, 21 evaluated semen parameters, 18 evaluated reproductive hormones, and 3 evaluated time to pregnancy.
What was found
The abstract does not provide specific point estimates, confidence intervals, or numerical effect sizes. The authors reported that higher urinary DEHP metabolite concentrations showed inconsistent associations with higher proportions of spermatozoa with DNA damage, lower sperm concentration, and decreased sperm motility. A negative association between DEHP metabolites and circulating testosterone levels was reported to be more consistent. Three studies evaluating time to pregnancy showed no apparent association with DEHP metabolites.
Why it matters
DEHP is a widely used industrial plasticizer, and understanding its endocrine-disrupting potential in adult men helps clarify environmental risks to male reproductive health.
Limits
The underlying evidence base is overwhelmingly cross-sectional (28 of 33 studies), precluding causal conclusions due to the risk of reverse causality, residual confounding, and exposure misclassification from short-lived urinary metabolites. Data on clinical fertility endpoints like time to pregnancy were very sparse (only 3 studies), and reported semen quality associations were inconsistent across studies.
Cited by
- supports Elevated phthalate levels in adult men are linked to lower sperm quality and decreased testosterone.