Endocrine Characteristics of 246 Cases of Childhood-Onset Anorexia Nervosa in Japan: A Single-Center Experience

Anorexia nervosa (AN) is associated with multiple endocrine abnormalities resulting from chronic food deprivation due to patients' persistent efforts to maintain thinness. Most available data are derived from adult populations, whereas pediatric data remain relatively limited. We aimed to evaluate the endocrinological characteristics of children with AN. We conducted a retrospective, single-center study of 246 Japanese patients with AN who met the eligibility criteria between January 2013 and December 2022. Physical characteristics were collected, and their correlations with various endocrinological measurements were analyzed. Insulin-like growth factor I standard deviation score (IGF-1 SDS) was positively correlated with body mass index SDS (BMI SDS) (R = 0.405, p < 0.0001) and negatively correlated with growth hormone (GH) (R = -0.424, p < 0.0001). Despite elevated GH secretion, IGF-1 levels were low, indicating GH resistance. Free triiodothyronine was positively correlated with BMI SDS (R = 0.381, p < 0.0001). Moreover, luteinizing hormone and follicle-stimulating hormone levels were positively correlated with BMI SDS (R = 0.365, p < 0.0001 and R = 0.409, p < 0.0001, respectively). Adrenocorticotropic hormone (ACTH) showed no correlations with BMI SDS (R = -0.031, p = 0.677), whereas cortisol was negatively correlated with BMI SDS (R = -0.321, p = 0.0107). In summary, this study of 246 patients with childhood-onset AN demonstrated that children, similar to adults, exhibit GH resistance and central hypogonadism. However, unlike in adults, ACTH elevation was not observed.