DEER involved a process of “continual assessment”, following newborn babies' progress to puberty and beyond. Initially, the project team analysed the existing studies involving human newborns with their associated analyses of chemical exposure. Following this, they used existing animal and laboratory models to study the development and function of testes during development. The complexity of real-life chemical exposures and the effects on the subjects studied were then tackled.

Results under DEER are intriguing. By analysing breast milk, the scientists found that exposure to endocrine disruptors, or chemicals that interfere with the hormone system in animals, was distinctly higher in Denmark than in Finland. This may be linked to the finding of a higher percentage of Danes having testes located incorrectly in the body at birth.

Studies on the young men also showed continuous poor semen quality in Denmark and a deterioration in Finland possibly due to exposure to these chemicals. Meanwhile, dibutyl phthalate, which is a widely-used plasticiser, was also found to exert its adverse effects on the reproductive development of experimental animals. Finally, research also showed that the onset of puberty, particularly in girls, can also be hampered by exposure to environmental chemicals.

“The studies will be useful tools for the assessment of chemical safety and be instrumental in the work of the European Chemicals Agency to implement the REACH (Registration, Evaluation and Authorisation of Chemicals) programme,” says DEER Project Coordinator, Professor Jorma Toppari.

The wealth of new data generated in the DEER project will continue to produce new analytical results that will be published and publicly presented. These findings will be disseminated to policymakers and other stakeholders, as well as to the wider public. 

Interestingly, the results of the DEER project have already influenced the World Health Organisation’s (WHO) study on the possible effects of endocrine disruptors on child health. For Professor Toppari, the next steps include a study on the soon to be 19 year olds in 2016.