The descriptive epidemiology of congenital and acquired cryptorchidism in a UK infant cohort

Carlo L Acerini ^1*, Harriet L Miles ¹, David B Dunger ¹, Kenneth K Ong ² and Ieuan A Hughes ¹

¹ University of Cambridge, United Kingdom
² MRC Epidemiology Unit, Cambridge, United Kingdom

^* To whom correspondence should be addressed. E-mail: cla22{at}cam.ac.uk.

Accepted 18 May 2009

Abstract

Introduction: Recent studies in other European countries suggest that the prevalence of congenital cryptorchidism continues to increase. We aimed to explore the prevalence and prognosis of congenital cryptorchidism in a UK centre.

Methods: Between October 2001 to July 2008, 784 male infants were born in the prospective Cambridge Baby Growth Study. 742 infants were examined by trained research nurses at birth; testicular position was assessed using standard techniques. Follow-up assessments were completed at ages 3, 12, 18 and 24 months in N=615, 462, 393, and 326 infants respectively.

Results: The prevalence of cryptorchidism at birth was 5.9% (95% CI: 4.4-7.9%). Congenital cryptorchidism was associated with earlier gestational age (p<0.0001), lower birth weight (p<0.0001), birth length (p<0.0001), and shorter penile length at birth (p<0.0001) compared to other males, but normal size after age 3 months. The prevalence of cryptorchidism declined to 2.4% at 3 months, but unexpectedly rose again to 6.7% at 12 months due to new cases. The cumulative incidence of "acquired cryptorchidism" by age 24 months was 7.0% and these cases had shorter penile length during infancy than other infants (p=0.003).

Conclusions: The prevalence of congenital cryptorchidism was higher than earlier estimates in UK populations. Furthermore our study for the first time describes acquired cryptorchidism or "ascending testis" as a common entity in male infants, which is possibly associated with reduced early postnatal androgen activity.