Is the incidence of hypospadias increasing? Analysis of Finnish hospital discharge data 1970-1994

Reports suggesting an increasing incidence of male genitourinary anomalies such as hypospadias, possibly related to environmental factors such as envi ronmental estrogen-like compounds, have recently received considerable publ icity These reports are based on birth defects registry data, and there may be variation in the completeness of the registries used. We analyzed tempo ral trends in the prevalence of hypospadias in Finland to assess the previo usly reported low overall prevalence and to detect any possible increasing tendencies during the past decade. We identified all patients who were surg ically treated for hypospadias before the age of 9 years among boys born 19 70-1986 in the national hospital discharge registry. We calculated the cumu lative prevalence by dividing the number of patients by the number of male births, and we used Poisson regression analysis. Out of 549,176 boys born i n Finland in 1970-1986, 1,543 were treated for hypospadias by the age of 8 years (28.1 surgically treated patients per 10,000 male live births; 95% co nfidence interval, 26.7-29.5). The prevalence of hypospadias in Finland rem ained constant throughout the study period and appears to have been approxi mately three times higher than previously reported. Changes in completeness of registration may account for a substantial proportion of the reported i ncreases in the prevalence of hypospadias in Finland and possibly also else where.