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The average age when European children reach puberty is declining - for some girls it can now be as low as eight years. Early maturity makes life more difficult. Children may be subjected to teasing or bullying from their social group and also run the risk of future health problems, ranging from early pregnancy to increased rates of some cancers. Many factors are implicated in this early maturation: the increase in childhood obesity, genetic make-up, the type of food eaten, and chemicals in the environment are the most suspect. But work is needed to evaluate and quantify their effects and the interactions between them. The main aims of the PIONEER Specific Targeted Research Project are to provide the evidence to assess the extent and causes of the trend and to see if measures are needed to counter it.


A team of experts in clinical and experimental sciences is carrying out the three-year project. They will collect extensive data from many regions across Europe about the age at which puberty starts in children. The next stage will be to develop genetic information about maturation, starting with the strong evidence that already exists for a constitutional tendency towards delayed maturation. Large population studies including identical twins, obese children and controls, will pinpoint candidate genetic traits that may control the onset of puberty.

Childhood obesity, an increasing problem in developed countries, is also linked to maturation - plump girls often reach puberty early, while overweight boys tend to mature late. Obesity appears to run in families, so PIONEER is also looking for a potential genetic link between the predisposition for obesity and the onset of puberty. Children may be at risk through genetic factors that control appetite, too.


There is no doubt that genes influence the timing of growing up, but physiological and environmental factors also play their part. The food children eat can simply make them overweight but the effects of chemical content will be an important part of the study. Immature organs are susceptible to exposure to chemicals during critical stages of development and may even be permanently impaired. Most damaging might be man-made or natural chemicals that mimic our own (endogenous) hormones and disrupt developing endocrine systems.

Nutritional and genetic factors do not act in isolation but interact in a complex way that is not well understood at present. Existing studies of large numbers of obese and other children will form the basis of an exploration of these interactions. The project will deliver a greater understanding of the genetic, physiological and nutritional factors that interact to advance sexual maturity.

PIONEER is also working on new experimental models that will speed up the study of exogenous and endogenous influences on the onset of puberty. It will use in bred strains of mice with early or late onset of puberty for phenotype characterisation and genetic analysis. It will establish the chromosomal loci responsible for the timing of puberty and use them to identify the genes responsible for the differences in this timing between the two mouse strains. The mice will then be used to study the effect of nutrition on their maturation, and how it interacts with the individual genotype.

The results of PIONEER will provide evidence on whether the EU needs to take specific action to prevent children from maturing sexually too early. This will contribute to the general health and well-being of EU citizens. The project will also enable longer-term systematic collection and analysis of data as to when Europe's children reach puberty.

List of Partners

  • University of Turku (Finland)
  • Karolinska Institute (Sweden)
  • University of Rome (Italy)
  • The AGA Khan University (Pakistan)
  • CNRS (France)
  • Kuopio University Hospital (Finland)
  • University of Helsinki (Finland)
  • Hungarian Academy of Sciences and Semmelweis University (Hungary)
  • Imperial College London (UK)
  • University of Leipzig (Germany)
  • Charite-University- Medicin, Berlin (Germany)
Full title:
Puberty onset - influence of environmental and endogenous regulators
Contract n°:
Project co-ordinator:
Sari Mäkelä, University of Turku,
EC Scientific Officer:
Wilfried Diekmann,
EU contribution:
€ 3M
Specific Targeted Research Project

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Last update: 06 December 2007 | Top