Phthalate exposure and male reproductive outcomes: A systematic review of the human epidemiological evidence.
Level 1 - systematic review of randomized trials
Systematic review of human epidemiological studies (by design analogy, not clinical CEBM)
PubMed 30336412 · doi:10.1016/j.envint.2018.07.029
What was done
Authors conducted a systematic review searching PubMed, Web of Science, and Toxline to assess associations between human exposure to six phthalates (DEHP, DINP, DBP, DIBP, BBP, DEP) and male reproductive outcomes. Two reviewers evaluated studies using a priori criteria for risk of bias and sensitivity, synthesizing evidence across outcomes with a structured framework.
What was found
The review evaluated six primary outcomes (counts of included/excluded studies reported in abstract): - Anogenital distance: 6 included, 1 excluded - Semen parameters: 15 included, 9 excluded - Time to pregnancy: 3 included, 5 excluded - Testosterone: 13 included, 8 excluded - Timing of pubertal development: 5 included, 15 excluded - Hypospadias/cryptorchidism: 4 included, 10 excluded No meta-analytic effect sizes or numerical statistics were reported in the abstract. Qualitative synthesis revealed robust evidence of association with male reproductive outcomes for DEHP (anogenital distance, semen parameters, testosterone) and DBP (semen parameters, time to pregnancy); moderate evidence for DINP (testosterone, semen parameters) and BBP (semen parameters, time to pregnancy); and slight evidence for DIBP and DEP.
Why it matters
This systematic review demonstrates that typical human population exposure levels to specific phthalates, notably DEHP and DBP, are consistently associated with endocrine disruption and adverse male reproductive health outcomes.
Limits
The abstract provides qualitative certainty ratings rather than quantitative pooled effect estimates. The total participant sample size is not stated, high exclusion rates occurred for several outcomes (such as pubertal timing and congenital anomalies), and evidence for certain congeners (such as DIBP) was restricted by few available studies and lower exposure levels.
Cited by
- supports Phthalates act as anti-androgenic chemicals that lower androgen/testosterone levels.