The occurrence of anorexia nervosa (AN) during childhood or adolescence rapidly induces starvation, stop of growth and impaired mineralization of bone tissue together with an interruption of pubertal development. These consequences are initially reversible following food intake return but can lead to a more irreversible status with low height, osteoporosis and high fracture risk. The onset of the disease more and more early in life, with the first stages of puberty suggest that these consequences will be even more severe as bone resistance will be damaged by more profound effects on bone growth as well. It is therefore critical to evaluate these bone metabolism alterations in order to better manage these patients.

At every age and in every clinical circumstance either physiologic or pathologic, high resolution peripheral quantitative computerized tomography (HRpQCT) provides an evaluation of bone microarchitecture that is more informative than the global quantitative assessment given by conventional Dual Energy X-ray Absorptiometry) DEXA, with a better estimate of clinical fracture risk.

Here, we propose to measure cortical parameters, such as cortical thickness which plays a key role in bone biomechanical strength in young adults aged between 20 and 30 years-old, who had developed AN as early as the during the first stages of puberty but no longer present, compared to age-and sex-matched healthy volunteers. Other micro-architectural parameters will also be studied. In an exploratory phase, we will evaluate these bone microarchitectural parameters together with bone biological turnover markers and markers of sexual maturation in adolescents or young adults 20 years-old or less, undernourished and currently managed for AN.

Inclusion Criteria:

• Patients over 20 years old:

  • Age > 20 and < 30 years old
  • Patients managed for AN in the pediatric or endocrinology of the university hospital of St-Etienne
  • Patients who developed AN as early as the during the first stages of puberty defined by Tanner stage 1 to 4, with a diagnosis of AN based on DSM-IV current criteria:
  • Weight loss : deny of maintaining body weight over minimal normal threshold (85 % age and height matched)
  • Intense fear of gaining weight or becoming obese despite weight insufficiency;
  • Impaired perception of weight or dysmorphophobia;
  • Excessive role of weight or body shape in self-esteem or deny of current leanness;
  • Secondary amenorrhea during 3 or more menstrual cycles in young girls or primary amenorrhea
  • Duration of AN of at least 6 months
  • BMI >85% of theoretical BMI (efficient renutrition)

• Patients less than 20 years old :

  • Age > 10 and < 20 years old
  • Patients managed for AN in the pediatric or endocrinology of the university hospital of St-Etienne
  • Patients who developed AN as early as the during the first stages of puberty defined by Tanner stage 1 to 4, with a diagnosis of AN based on DSM-IV current criteria:
  • Weight loss : deny of maintaining body weight over minimal normal threshold (85 % age and height matched)
  • Intense fear of gaining weight or becoming obese despite weight insufficiency;
  • Impaired perception of weight or dysmorphophobia;
  • Excessive role of weight or body shape in self-esteem or deny of current leanness;
  • Secondary amenorrhea during 3 or more menstrual cycles in young girls or primary amenorrhea
  • Duration of AN of at least 6 months

Exclusion Criteria:

• Renal insufficiency
• Cushing
• Dysthyroidism
• Inflammatory disease
• Pregnancy
• Lack of consent
• Subject under legal protection