Blood Parameters in Children and Adolescents With Underweight and Atypical Anorexia Nervosa

Objective: This study aimed to identify biochemical, hematological, and endocrinological abnormalities in a sample of children and adolescents with underweight AN and atypical AN and to compare these results between the two groups. Method: Based on the 5th BMI-percentile admission, adolescents with underweight AN (n = 520) and atypical AN (n = 255) were included and medical records were reviewed. Results: Low prealbumin (35%) and neutropenia (39%), and several abnormalities in endocrinological parameters (50%) were the most common alterations found in the whole sample. Compared to the atypical AN group, the underweight AN group had significantly higher frequencies of elevated cholesterol (OR = 2.50; p < 0.001) and alanine aminotransferase (OR = 0.22; p = 0.005) and of reduced insulin-like growth (IGF) factor-1 (OR = 0.29; p < 0.001), T3 (OR = 0.46; p < 0.001), luteinizing hormone (OR = 0.24; p < 0.001), follicle stimulating hormone (OR = 0.58; p = 0.004), and 17b-estradiol (OR = 0.39; p < 0.001). However, other blood parameters showed similar alterations in both groups. Discussion: Both groups showed abnormalities in the same blood parameters, but some abnormal parameters were more common in the underweight AN group. These results suggest that atypical AN and underweight AN could present similar risks of certain medical complications.