Investigators from multiple institutions conducted a case-control study to assess the association of in utero exposure to polybrominated diphenyl ethers (PBDEs), a common flame retardant added to consumer products, and infant hypospadias. Parent participants were eligible as cases if they (a) were biological mothers of infant sons diagnosed with isolated hypospadias by a pediatric urologist at the study institution, (b) were ≥18 years old, and (c) resided in the same household for the duration of their pregnancy and up to the time of study participation. Controls were mothers with the same characteristics, but whose sons did not have hypospadias. Hair samples were collected from infants and case and control mothers, as maternal hair PBDEs have been found to correlate with maternal body burden of PBDEs.1 Case and control participants were also asked to complete a questionnaire about demographics, pregnancy, and their child’s birth history.
Investigators compared total maternal hair PBDE levels among case and control parent participants with sufficient hair samples. Among case and control parent participants with completed questionnaires, investigators adjusted maternal PBDE levels for potential demographic and clinical confounders. Infant hair PBDE levels were also compared to maternal PBDE levels.
There were 152 case and 64 control parents with sufficient hair samples for analysis; of these, 89 case parents and 54 control parents completed questionnaires. There was no difference in demographic and clinical characteristics between cases and controls, except case infants had a significantly lower birth weight. The median age of case and control infants at study participation was 8 and 10.5 months, respectively.
Total PBDE levels were significantly higher in case parents than controls (51.4 pg/mg vs 35.8 pg/mg; P=.02). After adjusting for potential confounders, this association remained significant with a 48.2% (95% CI, 23.3%, 65.4%) higher PBDE level in case (vs control) parents. Case infant PBDE levels were significantly higher than case parent PBDE levels (P<.05) and, among the entire study population, maternal PBDE levels did not correlate with infant levels.
The investigators conclude that mothers of infants with hypospadias had higher PBDE levels in their hair than mothers of infants without hypospadias.
Dr Dubik has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.
Synthetic flame retardants such as PBDE have been used extensively since the 1970s to reduce the risk of combustion, and they are ubiquitous in the environment.2 Plastic can integrate up to 15% PBDEs, and polyurethane foam up to 30% PBDEs.3 However, PBDEs are additives and not chemically bonded to the plastic or foam; they can leach out as the product ages and are highly resistant to degradation.4 Individuals may...