AGE Accumulation in Patients on Long-term Parenteral Nutrition

Inclusion Criteria: * Patients (adults and children, all ages) initiating long-term parenteral nutrition * Followed at CHU de Bordeaux or Robert Debré Hospital (APHP) * Covered by French Social Security system * Written informed consent obtained from patient (if adult) or legal guardian (if minor) Exclusion Criteria: * Fitzpatrick skin type ≥ V (darker skin tones) * Forearm tattoos at the site of measurement * For patients included under 1 year of age: patients born prematurely (before 37 weeks of amenorrhea) * Pregnant or breastfeeding women.