May 22, 2008 (Orlando, Florida) — Higher incidences of congenital anomalies, including cryptorchidism (undescended testicles) and hypospadias, are found in boys whose mothers had higher serum levels of certain organohalogen compounds, according to 2 studies presented here at the American Urological Association (AUA) 2008 Annual Meeting.
The new research confirms existing hypotheses, that maternal exposure to endocrine-disrupting chemicals, including total polychlorinated biphenyls (PCBs), such as Aroclor, and organochlorinated pesticides, such as dichlorodiphenyltrichloroethane (DDT), contributes to an increased incidence of these conditions.
Undescended testicles, if left untreated, can lead to infertility and a greater risk of developing testicular cancer. Hypospadias occurs when the urethral opening is not positioned at the tip of the penis. Hypospadias can range in severity, depending whether the urethral opening is only slightly displaced on the glans penis, is on the shaft of the penis, or is not on the penis at all (third degree). Hydroceles are fluid-filled sacs surrounding a testicle that require treatment, either surgical excision or needle aspiration, when large enough to cause disfigurement or discomfort.
In a study of 40 boys undergoing surgical treatment for undescended testes, researchers from New York and Michigan analyzed PCB serum levels from both the patient and the mother, and compared the readings with residual PCB levels in the patient's fatty-tissue samples taken during surgery. Patients ranged from 8 to 18 months of age at the time of treatment.
The amount of organochlorine-compound (OCC) residue in the samples revealed that serum PCB levels reflect the fatty burden of OCC residue in the boys, and OCC concentration in maternal serum samples correlated with the sons' serum levels. Aggregate PCB levels and levels of individual PCB congeners were significantly higher in mothers of boys with undescended testicles than in mothers of boys without the anomaly.
Researchers from Michigan and Atlanta, Georgia, presented similar findings on congenital anomalies and chemical exposure. Using data from the Michigan Long-Term PBB Cohort, researchers examined individuals exposed to polybrominated biphenyl (PBB) in 1973 and 1974, including sons of mothers with known serum PBB levels, to determine whether in utero exposure to PBB put male neonates at greater risk for genitourinary or reproductive conditions. Self-reported data on varicocele, cryptorchidism, hypospadias, and other genitourinary and reproductive conditions were compared with estimated maternal PBB levels at the time of conception.
Of the boys whose mothers had measurable PBB levels at the time of conception, 35 reported genitourinary conditions: 13 reported hernias, 10 reported hydroceles, 9 reported undescended testicles, 5 reported hypospadias, 2 reported phimosis, and 1 reported varicocele. Boys whose mothers had PBB levels greater than 5 parts per billion were more likely to report these conditions than those whose mothers had lower levels. Maternal PBB levels were not found to have an impact on birth weight or estimated gestational age. Among boys with mothers who had serum levels greater than 5 parts per billion, 12.2% reported genitourinary conditions; among boys whose mothers had lower PBB levels, 5.5% reported genitourinary conditions.
Initially lauded for their chemical stability, PCBs (such as Araclor and its congeners) and organochlorinated pesticides (such as DDT) are lipid-soluble compounds actively produced around the world in the first half of the 20th century. After widespread use in agricultural and manufacturing applications (such as plasticizers, heat-stabilizing additives for polyvinyl-chloride electric insulation, adhesives, and paints), they were discontinued in the 1970s when health risks became apparent. The compounds are absorbed and dispersed to living tissue; as a result, they can have a cumulative effect and cause toxin damage across generations. The United States banned their domestic production in 1977.
John J. DeCaro, MD, from the Emory University School of Medicine in Atlanta, who was principal investigator on the Michigan Long-Term PBB Cohort, said most of the compounds are fairly ubiquitous.
"So as far as telling a mother whether or not she has been exposed, she probably has been,'' Dr, DeCaro told Medscape Urology. "The question becomes how long has she been exposed [and to which compounds]."
Anthony Y. Smith, MD, from the University of New Mexico, in Albuquerque, and a member of the AUA Public Media Committee, said mothers with known exposure to these enduring compounds should tell not only their doctors but also their sons' pediatricians.
"These data underscore the importance of regular 'well-baby checkups' so that these easily treatable conditions are diagnosed promptly," said Dr. Smith, who was not involved with the presentation.
American Urological Association 2008 Annual Meeting: Abstracts 276 and 277. Presented May 18, 2008.
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Cite this: Stephanie Doyle . Pollutants Linked to Urologic Conditions in Infant Boys - Medscape - May 22, 2008.