ID in children is the most frequent micronutrient deficiency in industrialized countries, including France. ID induces neurological impairment reducing cognitive, motor, and behavioral capacities in children in the short and long term.

The purpose of this study is to evaluate the principal determinants of ID in France in two-year-old children and to improve strategies for prevention and screening.

The main objective is to study the association between iron status in two-year-old infants living in France and the consumption of toddler milk formula after taking non-dairy iron ingestion, parental socioeconomic status and educational level into account.

The secondary objectives are the following :

• to estimate the prevalence of ID and ID anemia in 2-year-old children living in France.
• to improve clinical tools for ID screening. to improve strategies for laboratory screening.

The general methodology planned is a nationwide observational cross-sectional study including a blood sample and nutritional survey. 100 pediatricians will include children from 21 regions different from a geographic and a dietary point of view. Each pediatrician will include 10 children consecutively including 3 with the french medical healthcare coverage called CMU (which is a precariousness marker).

The study will take place according to the following plan and procedures for each child: D1 recruitment in the physician-investigator's office (verification of inclusion criteria and collection of the first parent's consent, clinical data collection, prescription for blood test and delivery of the kit containing the elements needed for the study for the patients); between D8 and D15, performance of the standard laboratory tests to be performed locally in the medical laboratory normally used by the family, and the sending of samples for specific analyses (especially biochemistry) to reference laboratory that will perform all these analyses for this study; between D2 and D7, a 3-day food survey based on a food diary (see below); between D20 and D60, final study visit to the doctor's office (help in completing the food diary, discussion of the laboratory results, prescription of iron treatment if needed). The blood sample and/or the 3-days food survey will be delayed 15 days if any intercurrent disease which may interfere with biological markers or food intake (for example acute gastro-enteritis, fever) appears after D1 of inclusion.

Inclusion Criteria:

• Infants aged 22-26 months
• living usually in France
• written agreement of one parent or the holder of parental authority
• followed-up by a liberal paediatrician
• with social coverage

Exclusion Criteria:

• chronic disease known at inclusion that might affect iron metabolism or reserves : blood transfusion since birth, celiac disease, chronic inflammatory disease, including of the intestines, cystic fibrosis, other enteropathy, enteral nutrition for more than 15 days in the past 6 months, chronic hemolytic diseases, chronic kidney disease, hemophilia, or chronic bleeding, such as ENT or gastrointestinal, hemochromatosis, any malignant condition, or lead poisoning)
• participation to another study