The incidence of hypospadias in two English cities: a case-control comparison of possible causal factors

To determine the incidence and severity of hypospadias amongst children born in Southampton and Portsmouth during 1992-94, and to identify possible causal factors by comparing patients with a control group.

All patients with hypospadias born in Southampton and Portsmouth during 1992-94 were identified. The Southampton cases were matched with controls; the case notes of each affected child were reviewed. The incidence determined by this study was compared with data provided by the Central Statistics Office.

There was no apparent increase in the incidence of hypospadias in Southampton and Portsmouth during 1982-94. However, there was a clear local variation in incidence, with a significantly lower incidence in Portsmouth than in Southampton and the rest of England and Wales. The severity of hypospadias was also more marked in Southampton than in Portsmouth. The only recognisable aetiological factor was a positive family history, supporting the concept of a polygenic mode of inheritance. All the environmental factors investigated were unrelated, but there was a suggestion of clustering in a single water-quality zone.

This study identified no increase in the incidence of hypospadias but it did detect local variations in both the incidence and severity of the condition, and these need to be considered when planning surgical services.