The incidence of male genital tract abnormalities such as cryptorchidism (undescended testes) and hypospadias (abnormal site of urethral opening due to incomplete closure of the urethral folds during penis development) are also thought to be increasing in Western countries.15 A prospective study performed in Oxford between 1984 and 1988 reported that the incidence of cryptorchidism had increased by approximately 35% at birth and by 93% at three months in comparison to a similar study performed in the 1950s. i® The authors of this study used the same criteria for diagnosis of cryptorchidism in the 1980s as were applied in the 1950s, thus minimising the possibility that their results stemmed from altered diagnostic criteria. In contrast, a prospective study performed in the USA between 1984 and 1990 reported that the incidence of cryptorchidism had remained unchanged when compared to those reported several decades earlier. 17 However, this study has been criticised as it is heterogeneous with respect to the ethnicity of the subjects; it is well established that American blacks have a much lower incidence of cryptorchidism than do American whites. 13 Unfortunately, it is is difficult to gauge whether cryptorchidism is becoming more prevalent as there is a lack of studies in which the incidence of cryptorchidism has been examined with time, within the same population or geographical area using standardised criteria. Epidemiological trends in incidence of hypospadia are suggestive of an increase in several European countries, Australia and New Zealand, especially as there is thought to be substantial under-reporting of the mild cases.i3,i8 A multicentre study of seven malformation surveillance systems around the world showed that geographical differences existed in the prevalence of hypospadia at birth and that not all countries showed an increase in incidence. i® However, more convincing evidence of a change in prevalence comes from a recent American study based on data from two established surveillance systems, which has shown that the total number of cases of hypospadias has nearly doubled over the period 1968-1993.1® Both studies showed an increase in incidence of 2-3% per year; furthermore, the number of severe cases of hypospadia (the minority, but not under-reported) showed a similar or higher i5 G. Berkowitz, R. Lapinski, S. Dolgin, J. Gazella, C. Bodian and I. Holzman, Pediatrics, 1993,92,44.
i® B. Kallen, R. Bertollini, E. Castilla, A. Czeizel, L. Knudsen, M. Martinez-Frias, P. Mastroiacovo and O. Mutchinick, Acta Paediatr. Scand., 1986, suppl. 324, 1.
17 L. Paulozzi, J. Erickson and R. Jackson, Pediatrics, 1997, 100, 831.
18 H.-O. Adami, R. Bergstrom, M. Mohner, W. Zatonski, H. Storm, A. Ekbom, S. Tretli, L. Teppo, H. Ziegler, M. Rahu, R. Gurevicius and A. Stengrevics, Int. J. Cancer, 1994, 59, 33.
i® R. Bergstrom, H.-O. Adami, M. Mohner, W. Latonski, H. Storm, S. Tretli, L. Teppo, O. Akre and T. Hakulinen, J. Natl. Cancer Inst., 1996, 88, 727.
rate of increase, confirming that the results were not due to an improvement in the accuracy of reporting.
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