Table 5:
Updates to assessment of probable associations between exposures and outcomes in male reproductive health
| Outcome | Strength of human evidence (2015) | Probability of causation (2015), % | Updates to literature (since 2015) | |
|---|---|---|---|---|
| Prenatal PBDEs | Cryptorchidism | Low | 40–69% | One study reports a positive association |
| Prenatal PBDEs | Testicular cancer | Very low to low | 0–19% | No new evidence |
| Occupational pesticides | Prostate cancer | Not assessed | Not assessed | Evidence for increased risk with exposure to persistent pesticides from studies in diverse geographical regions |
| Adult phthalates | Low testosterone (resulting in increased early mortality) | Low | 40–69% | Increased evidence for negative association with testosterone in cross-sectional studies (n=13; all but one for DEHP and MEHP, two for MiBP); association of prenatal exposure and testosterone in children, adolescents, and young men was not as consistent |
| Adult BPA and BPS | Semen quality | Not assessed | Not assessed | Six studies show negative associations with concentration of sperm and total sperm count; negative associations with motility (n=3), morphology (n=2), and reduced semen quality (n=1); two studies found no associations, one study found positive association for motility and concentration; one study of BPS shows negative associations with total sperm count, concentration, motility, and normal morphology |
| Adult PFAS | Semen quality | Not assessed | Not assessed | Four studies consistently associated higher concentrations of PFAS with lower semen quality (three of morphology, one of motility) |
| Organophosphate pesticides | Semen quality | Not assessed | Not assessed | Three studies consistently associated higher concentrations of organophosphate pesticides with lower semen quality (sperm concentration, motility, and morphology) |
| Adult benzyl and butyl phthalates | Male infertility (resulting in increased use of assisted reproductive technology) | Low | 40–69% | 22 more studies linked higher phthalate concentrations to lower sperm concentration, motility, or normal morphology; three studies had increases in these measures; three studies showed no significant association |
Adapted from the data first reported in Trasande et al (2015)11 and updated in Trasande et al (2016).12 See appendix for full list of studies mentioned here that have updated the literature (appendix pp 31–40). PBDE=polybrominated diphenyl ethers. DEHP=di-2-ethylhexyl phthalate. MEHP=mono-2-ethylhexyl phthalate. MiBP=monoisobutyl phthalate. BPA=bisphenol A. BPS=bisphenol S. PFAS=perfluoroalkyl substances.