The epidemiology of cryptorchidism and potential risk factors, including endocrine disrupting chemicals.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing epidemiological cohorts, ecological studies, and animal mechanism models.
PubMed 38633762 · doi:10.3389/fendo.2024.1343887
What was done
This narrative review summarizes epidemiological and mechanistic evidence regarding congenital cryptorchidism, its clinical course, gestational determinants, and potential environmental risk factors including endocrine-disrupting chemicals.
What was found
Prospective cohort studies report cryptorchidism prevalence ranging from 1% to 9%, with temporal trends and geographic variation. Normal testicular descent completes by gestational week 35. Preterm birth, low birth weight, intrauterine growth restriction, and maternal smoking are identified as risk factors. The abstract notes that associations with endocrine-disrupting chemicals are corroborated in rodents and supported by ecological studies, but provides no specific quantitative effect estimates or numerical chemical exposure metrics.
Why it matters
Cryptorchidism is a common congenital defect associated with adult impaired semen quality and testicular cancer. Synthesizing known maternal and environmental risk factors helps inform clinical surveillance and public health chemical safety discussions.
Limits
The paper is a narrative review with no systematic methodology or pooled sample size provided in the abstract. Causal inference for endocrine-disrupting chemicals in humans is severely limited by ubiquitous, simultaneous exposures to complex chemical mixtures and reliance on ecological and animal data.
Cited by
- contradicts Approximately 20% of male infants are born with an undescended testicle.