Endocrine Abstracts

Introduction: Santé publique France develops a national epidemiological monitoring program to study health indicators related to endocrine disruptor exposure. Based on the weight of evidence, cryptorchidism was selected for this purpose. In this study, we aimed to analyze temporal, spatial and spatio-temporal trends of cryptorchidism during the period 2002–2014 in France, and explore and/or generate environmental hypotheses.

Methods: We built an indicator reflecting incident operated cryptorchidism in boys under the age of 7, using the data of the French National Hospital Discharge Database (PMSI). We fitted temporal, spatial and spatio-temporal models to describe trends of the risk of cryptorchidism at the department and at the postal code scale. We used Kulldorff’s spatial scan statistic and Tango’s flexibly shaped spatial scan statistic to identify spatial clusters at the postal code scale. We studied all types of cryptorchidism and bilateral cases separately. We searched for demographic, economic and environmental shared characteristics within clusters to discuss environmental hypotheses.

Results: We identified 91400 new cases of operated cryptorchidism in boys under the age of 7 years, including 9799 (10.7%) bilateral cases. The observed incidence was equal to 2.14 /1000 in 2002 and to 2.81/1000 in 2014. In the study period, the estimated increase of operated cryptorchidism incidence was equal to 37.1% (31.5%; 42.9%), especially among boys under 2 years and bilateral cases. An increase was observed in all departments, including ultramarine territories. The risk of cryptorchidism presents structured spatial heterogeneity. We detected 24 spatial clusters scattered in Metropolitan France. Low socio-economic levels were often observed in the cluster areas. Potential environmental exposures included mining activities (8/24 clusters), metallurgy (17/24 clusters) and mechanics (16/24 clusters). We also detected 21 spatial clusters of bilateral operated cryptorchidism, in the same areas and in a few agricultural areas.

Discussion, conclusion: To our knowledge, this is the first descriptive study on cryptorchidism addressing the issue of environmental exposure nationwide, with a large sample. As regards environmental hypothesis, this is an exploratory study, with limits due to the indicator built from hospital discharges and lack of individual data. Among some of the identified, environmental exposures related to mining and metallurgy could have induced persistent environmental pollution to metals, metallurgy inducing in addition dioxins and PCBs. This study analysis should be considered as a hypothesis-generating process for future research studies.