Hypospadias is a congenital medical condition where the urethra forms abnormally on the penis. Researchers believe the condition may be associated with chemicals that disrupt the endocrine system, specifically organochlorine pollutants, otherwise known as POP.

Data for the study was pulled from a Swedish cohort. Samples of serum were collected for the study, so researchers had access to exactly what they needed to test for environmental pollutants like POP. The cohort was linked to a Malformation Register in the same region.

Between 1986 and 2002, 390 cases of hypospadias were reported via women in the Swedish cohort. Only 237 serum samples were tested because not enough serum was available in the remaining 153 cases. A control was chosen from the Swedish cohort for each of the affected children. Controls were partnered based on common characteristics like maternal age and year of birth.

There did not appear to be any correlation between serum POP level and hypospadias until researchers looked at the top quarter of serum concentrations. When serum levels of POP reached above 26 ng/ml more cases of hypospadias appeared.

Concluding: Fetal exposure to POP that results in serum levels above 26 ng/ml may be associated with an increased risk of hypospadias.

Source: Rignell-Hydbom A, Lindh CH, Dillner J, Jönsson BA, Rylander L. A nested case-control study of intrauterine exposure to persistent organochlorine pollutants and the risk of hypospadias. PLoS One. 2012;7(9):e44767. doi: 10.1371/journal.pone.0044767. Epub 2012 Sep 27.