Rates of orchiopexies in Sweden: 1977-1991.

Cryptorchidism is a known risk factor for testicular cancer and the secular increase in testicular cancer incidence might have been paralleled by a similar increase in cryptorchidism. Data on trends in prevalence of cryptorchidism are however conflicting and decreases have recently been reported. To analyse Swedish trends in rates of orchiopexy, we used the Swedish Hospital Discharge Register to identify all cases of orchiopexy carried out for cryptorchidism between 1977 and 1991, that is, before the era of outpatient orchiopexies in Sweden. Observed trends were analysed in 5-year age groups. The estimated average annual per cent changes (EAPCs) and the years in which the EAPC significantly changed were estimated using Joinpoint Regression. Finally, we estimated the cumulative incidence of orchiopexy by birth cohort. Among boys aged less than 10, the orchiopexy rate started to decrease in the early 1980s. EAPCs were -2.88 (95% confidence interval (CI): -5.48, -0.21) among boys aged 5-9 and -6.63 among those aged 0-4 (95% CI: -8.84, -4.37). Among subjects aged at least 10, the rate decreased over the whole study period. Although the use of orchiopexy rates to measure prevalence of cryptorchidism has limitations, our findings may suggest that cryptorchidism prevalence decreased in Sweden starting from the early 1980s.